Elucidating morphogenic and physiological traits of rice with nitrogen substitution through nano-nitrogen under salt stress conditions

doi:10.21203/rs.3.rs-4015792/v1

Download PDF

Research Article

Elucidating morphogenic and physiological traits of rice with nitrogen substitution through nano-nitrogen under salt stress conditions

https://doi.org/10.21203/rs.3.rs-4015792/v1

This work is licensed under a CC BY 4.0 License

Journal Publication

published 30 Sep, 2024

Read the published version in BMC Plant Biology →

You are reading this latest preprint version

Background

Sustainable crop production along with best nutrient use efficiency is the key indicator of smart agriculture. Under abiotic stress conditions, nutrient uptake and translocation are restricted affecting plant growth and yield. The combined effect of nano-nitrogen and salt stress are very limited. Recent developments in slow releasing, nano-fertilizers in agriculture, begins a new era for sustainable use and management of natural resources. The aim of the study was to explore whether substitution with nano-urea could mitigate the detrimental effects of salt stress on plant growth and development along with physiological traits.

Results

With the onset of nano-formulations, this study was designed to explore the potential of nano-nitrogen by replacing traditional urea applications in 33, 50 and 60% doses on rice plant growth and development. Further, the strategic substitutions were compared in saline and sodic soils along with normal soils to dissect the beneficial response of nano-N in two rice varieties under saline stress of ECe ~ 6.0 dSm^− 1 and sodic stress of pH ~ 9.1. With saline and sodic stresses, plant RWC decreased by 10.33% and total chlorophyll content by 1.32–1.52%, gas exchange attributes by 10.42–38.8%, leaf area upto 29.9% and yield upto 3.92%, respectively. Leaf greenness (SPAD index) was significantly higher with Nano-N along with number of grains/panicle, crop growth rate and net assimilation rate. Results depicted superiority of nitrogen replacement through nano-N with 0.2–1.64% enhancement in growth traits, 0.93–1.85% in physiological traits, and 1.92% in yield over 100% recommended dose of urea on cumulative basis in rice. Between varieties, salt tolerant rice variety, CSR-10 performed better than Pusa 1121 in terms of morphological, physiological and yield traits under stress conditions and nitrogen substitutions.

Conclusions

Overall, our experimental findings depicted promising potential of nano-N for enhancing the physiological growth and yield under salt stress and also optimizing better yield in normal soils with 33% replacement of conventional urea.

Nano-nitrogen

physiological traits

basmati rice

CSR-30

salinity

PB1121

The world population is anticipated to approach 9.7 billion by 2050 [1] thereby, demanding high food availability and security. To meet this increased requirement, future crop production needs to be enhanced by 70% by combating the agricultural land degradation and climate change impact [2]. Globally rice and wheat are the major staple foods and being one of the predominating cropping systems on the Indian subcontinent, it could address food security and livelihood issues. Rice-wheat system occupies 12.3 million hectares area in Uttar Pradesh, Punjab, Haryana, Bihar, and West Bengal states of India [3]. For a better crop stand, plant nutrition, crop quality and agricultural production, 40–60 percent of the world's total agricultural production depends on the use of fertilizers. Among the major fertilizers, nitrogen (N), phosphorous (P) and potassium (K) play important roles in plant growth and development and in India, the combined consumption of fertilizers in rice-wheat cropping system amounts to 4.15 million tonnes (MT) of total nitrogen, 1.66 mt of P₂O₅ and 0.56 mt of K₂O [4]. N-use pattern of wheat-growers in sodicity affected Ghaghar Basin of Haryana, India, have been analysed to optimize and identify indicators of efficient N use in contrasting wheat cultivars for sustainable production [5]. In most agricultural situations, the utilization efficiency of nitrogen fertilizer (urea) is around 30–40% while that of phosphate is around 15–20% and hence, N and P are applied in excess. Excessive unused fertilizer input gets released into the environment polluting soil, air and water. Being a necessary component of chlorophyll, proteins, metabolites, and nucleic acids as well as required for the enzyme activities, nitrogen is an important nutrient for growth, development, yield and grain quality [6]. After application to agricultural system, fertilizers containing nitrogen are either immediately absorbed by plants in the form of ammonium and nitrate or transformed into other forms by oxidation. Leaching, volatilization, and denitrification are three processes that cause extra nitrogen to be eliminated in ionic or gaseous form [7] and nitrate is transported away by runoff or leached into the soil if not absorbed by plant roots. Application of extra nitrogen makes the nitrogen pool more phyto-available, magnifying the potential harm to the environment.

Therefore, for sustainable agriculture, judicious fertilizers use is crucial for reducing the negative impact of agriculture on the environment. Additionally, nitrogen fertilizer has also been used as a method for mitigating salinity consequences because of its crucial role in plant growth and development as well as for its osmoregularity effects, which mainly depends on the type and amount of fertilizer supplied, its pattern of mineralization over time and the salinity levels of the soil [8]. Due to high solubility in water, non-polarity, rapid leaf absorption, and low phytotoxicity, urea is the most commonly used N source for fertilization [9]. Currently, world-wide economic and environmental concerns revolve around achieving desired yield through efficient N usage and addressing the key issues of future global food demands. A wide range of smart fertilizers are being developed to adjust slow release of nutrients for plant requirements and thereby, increase nutrient use efficiency [10]. Increasing global human population has created the high food demand which has prompted the large-scale use of fertilizers. Additionally the natural resources of fertilizers are depleting, putting constraints for fertilizer availability and thereby, burdening extra cost for the farmers. Our nation's economy is based on agriculture which mainly depends on fertilizers that are essential for enhancing productivity but a vast amount of it is lost through leaching, denitrification, and volatilization triggering environmental pollution, eutrophication of waters, soil acidification, and biodiversity loss. Additionally, increasing salinization harnesses the agricultural profit and economic loss to farmers along with depletion of natural resources of fertilizers. Nanotechnology has been in use for agricultural sustainability through development of controlled and slow release techniques with targeted delivery of fertilizers or pesticides for plant nutrition and pest control and lower down the environmental impact [11, 12]. For coming generations, nano-fertilizer could be a viable option that might substitute the N usage due to their small size, high surface area-volume ratio, controlled delivery, easy absorption and high reactivity [13, 14]. Nano fertilizers provide several advantages over traditional fertilizers, including increased soil fertility and crop yield/quality metrics, non-toxic and reduced risk to humans and the environment along with reduced cost and increased profit. Therefore, the objective of this study was to evaluate the efficacy of recently commercialized nano-urea (The Indian Farmers Fertilizers Cooperative Limited, IFFCO) on plant performance of rice in controlled and saline environments with the goal of saving excessive use of nitrogen fertilizers.

The experiment was designed in a randomized block design in 20 kg porcelain pots for two years during 2020 and 2021. The experiment included three factors (Table 1) i.e. nitrogen treatment; soil type [normal soil of ECe ~ 0.62 dSm^-1& pH ~ 8.2; sodic soil of ECe ~ 0.91 dSm^-1 & pH ~ 9.1 and saline soil of ECe ~ 6.0 dSm^-1& pH ~ 8.3] and variety (CSR 30 Basmati and PB 1121, available with the first author from earlier experiments). CSR 30 is the first Basmati salt tolerant rice variety released by ICAR-CSSRI, Karnal, India in 2001 for salt affected areas with tolerance limit of salinity of EC 7.0 dS m^-1 and sodicity of pH upto 9.5. CSR-30 has medium-sized grain and a distinct aroma. The revenue generation based on export price from Basmati CSR 30 is Rs 1379 crores per annum during 2001–2019. Pusa Basmati 1121 (PB 1121) is a landmark Basmati rice variety released for commercial cultivation under normal soil conditions in 2003 by ICAR-IARI, New Delhi for its fine and slender extra-long grain. This basmati rice variety holds the world record for its highest kernel elongation on cooking and occupies more than ~ 70% of the total area under Basmati rice cultivation in India. This basmati rice varieties credit a monetary benefit of US$ 20.8 billion through export to various countries.

Before the conduct of experiment, the initial status of NPK in soil was measured as152-182 kg/ha N, 20.5-22.7kg/ha P, 245–270 kg/ha K and 0.55–0.71% OC. The recommended dose of nitrogen (RDN) for CSR 30 Basmati is 60 kg N/ha and for PB 1121 is 90 kg N/ha. Nano Biotechnology Research Center of IFFCO Gandhinagar, India, provided nano urea (500 ml containing 40000 ppm N) which is equivalent to 1 bag of urea (20.7 kg N). Recommended doses of Phosphorus (SSP) and Potassium (MOP) were applied in soil in all the treatments.

Table 1

Experimental plan of nitrogen treatments using conventional source as Urea and replacement with Nano-N
S. No.	Treatment	Basal dose (1/3rd N)	After 25 DAS (1/3rd N)	After 45 DAS (1/3rd N)
1.	Without Nitrogen - T1	-	-	-
2.	Recommended dose of nitrogen (RDN)- T2	Urea	Urea	Urea
3.	33% replacement of N- T3	Urea	Urea	Nano-N
4.	50% replacement of N- T4	Urea	50:50 (Urea + Nano-N)	Nano-N
5.	66% replacement of N- T5	Urea	Nano-N	Nano-N
6.	100% replacement of N- T6	Nano-N (Seed priming)	Nano-N	Nano-N

Rice seedlings (30 to 35 days old) were transplanted during first fortnight of July and the crop was harvested during first week of November respectively each year. Different morpho-physiological and yield traits were recorded at reproductive stage. Plant height, number of total tillers and effective tillers were recorded from 5 randomly selected plants per treatment. Leaf area was measured for five randomly selected leaves using Portable Laser leaf area meter (Model CI-202, Spectra Agritech). Total chlorophyll content (TCC, mg/g) was estimated using acetone method of Arnon [15] and leaf greenness was measuring using the SPAD meter (SAPD-502 Plus, KONICA MINOLTA, INC, Japan). The relative water content (% RWC) was estimated as per the procedure outlined by Barrs & Weatherly [16] and calculated using the formula [(Fresh weight-Dry weight)/(Turgid weight-Dry weight)]x100. The fully developed flag leaves were used to measure photosynthetic rate (Pn, umol m^-2 s^-1), stomatal conductance (gS, mol m^-2 s^-1) and transpiration rate (E, mmol m^-2 s^-1) using Portable Photosynthesis System (LI-6800, LICOR Inc., Lincoln, NE, USA). Cuvette conditions were maintained at a photosynthetic photon flux density (PPFD) of 1000 µmol m^-2 s^-1, relative humidity > 60%, ambient CO₂ concentration of 400 ppm and leaf temperature of 25°C [17]. Water use efficiency (WUE) was calculated as the ratio of photosynthetic and transpiration rate (Pn/E). Leaf area index (LAI) was measured using CI-110 Plant Canopy Imager (CID). Relative growth rate (RGR) was estimated as increment per unit biomass per unit time and expressed as mg g^-1day^-1. The Crop Growth Rate (CGR) explains the dry matter accumulated per unit area per unit time (g m^-2 day^-1). Net Assimilation Rate (NAR) is expressed as the milligrams of dry weight increase per unit dry weight or area per unit time (mg g^-1day^-1).Both the rice varieties were harvested manually at the time of physiological maturity. After harvesting, the plant produce was bundled, dried in the sun for 5–7 days and their weight was recorded. For each treatment, the data on biological yield and grain yield was expressed as g/pot. Before analysis, observations under each variable were tested for normality (Q-Q plot of residuals) through Shapiro-Wilk (W) test. Violated variables were transformed through appropriate transformation method. The data was statistically analyzed by General Linear Model (GLM) procedure for Randomly Complete Block Design (RCBD) using SAS software of Indian NARS Statistical Computing Portal (ICAR-IASRI, New Delhi) (stat.iasri.res.in/sscnarsportal). Pair-wise treatment comparisons were performed using the least significant difference at 5% level of significance.

The experiment was conducted for two years during Kharif- 2020 and 2021 to evaluate the effect of nano-N to replace/substitute the urea dose in rice. Non-significant variations for different traits were observed over the years; hence, the data was pooled and presented in three factorial completely randomized design (RCBD).

Morpho-physiological traits:

Plant height is an essential quantitative trait for above ground plant growth and development and is generally predictive of ultimate grain production and biomass, which is affected by environmental factors such as soil nutrition and climatic conditions. We observed that plant height was significantly affected by the soil type, saline or sodic (Table 2) where CSR 30 had higher plant height (98.14 cm) than PB-1121 (91.39 cm). Plant height decreased by 8–10% in both the stresses either sodicity or salinity but with different nitrogen substitutions, plant height was not significantly affected where treatments T3 (33% N replacement through nano-N) and T4 (50% N replacement through nano-N) depicted non-significant differences in comparison to T2 (recommended dose of urea). More than 50% substitution of urea with nano-N resulted in reduction of plant height and a significant interactive effect of variety, soil and N-management was observed. Relative water content represents appropriate measure of plant hydration state since it represents physiological consequence of cellular water deficit. Relative water content was more in PB 1121 (68.4%) than CSR 30 (63.05%) with little variation in soil type, i.e. 68.63% in normal soil, 67.01% in sodic soil and 61.54% in saline soil. Thus, RWC decreased more in saline soil (10.33%) than sodic soil (2.36%). N-substitutions have significant differences in RWC where, relative water content at 33% N replacement through nano-N, T3 (71.04%) was statistically at par with recommended dose of urea, T2 (70.39%). Further, substituting 50, 60, 100% N with nano-N resulted in reduction of RWC in range of 0.94%, 2.13% and 14.95% respectively in comparison to RDN, T2 (Table 2). Leaf chlorophyll is a vital photosynthetic pigment that largely determines plant greenness related to photosynthetic capability and ultimately plant development. Total chlorophyll content varied significantly within variety and soil types with higher content in CSR 30 and lower content in saline soils. Although, combination of urea and nano-N in all ratios showed statistical at par values for chlorophyll content (1.6–1.65 mg g^− 1 FW) still with application of nano-N replacing full N chlorophyll content decreased by 11.66–12.73%. Correspondingly, SPAD reading (measure of greenness in leaves) also showed significant variation among varieties, stress condition and different N-substitutions (Table 2). SPAD values reduced significantly (14%) in saline soils with higher values in variety, CSR 30 than PB 1121. Although the interactive effect of these factors was non-significant but leaf greenness was more with application of recommended dose of urea than the other nitrogen replacements of nano-N.

Gas exchange attributes:

Gas exchange traits including photosynthetic rate (Pn), stomatal conductance (gS), transpiration rate (E) and instantaneous water use efficiency (WUEi) showed a significant variability between varieties, soil types and N-substitutions (Table 2). CSR 30 variety had higher Pn, gS and E than PB 1121, whereas WUE was higher in PB1121. Pn reduced in the range of 18.5–21.3%, gS by 25.4–38.8% and E by 10.42–23.04% in sodic and saline stresses respectively with more reductions in saline conditions. With different nitrogen substitutions, T3 (33% N replacement through nano-N) had higher Pn (16.6 µmol m^− 2 s^− 1) followed by T2 (RDN) and T4 (50% N replacement through nano-N), whereas 50 & 100% N replacement depicted lower Pn value than T2 and T3. No significant differences were observed between stomatal conductance and transpiration rate among treatments, T2, T3, T4 and T5. Water use efficiency, WUEi (Pn/E) is the calculated value obtained from the ratio of photosynthetic rate to transpiration rate and notably higher WUEi was obtained under T1 and T6 treatment where no-nitrogen and 100% nano-N was applied respectively. Other treatments showed statistical at par WUEi values although the interactive effect of all the factors was significant except for soil × N-substitutions.

Table 2

Interactive effect of different N-substitutions on morpho-physiological traits in rice under salt stress conditions
Treatments/Traits	Plant height	RWC	TCC	SPAD	Pn	gS	E	WUE
Variety (V)
CSR 30	98.14^a	63.05^b	1.57^a	33.68^a	15.7^a	0.744^a	10.08^a	1.65^b
PB 1121	91.39^b	68.4^a	1.51^b	29.6^b	14.29^b	0.697^b	8.51^b	1.72^a
LSD (P = 0.05)	2.96	1.98	0.037	0.343	0.82	0.027	0.75	0.092
Soil type (S)
Normal soil	101.9^a	68.63^a	1.78^a	34.0^a	17.7^a	0.917^a	10.46^a	1.79^a
Sodic Soil	91.99^b	67.01^ab	1.52^b	31.53^b	14.43^b	0.684^b	9.37^b	1.63^c
Saline Soil	90.4^c	61.54^c	1.32^c	29.38^c	12.86^c	0.561^c	8.05^c	1.69^b
LSD (P = 0.05)	1.15	0.64	0.018	0.421	0.194	0.022	0.185	0.038
Nitrogen treatments (N)
Without N – T1	78.02^d	54.4^d	1.30^d	25.01^e	10.75^d	0.545^c	4.71^c	2.28^a
RDN through Urea – T2	100.72^ab	70.39^a	1.63^ab	35.99^a	16.38^ab	0.777^a	10.98^a	1.49^c
33% N replacement [⅓ Urea + ⅓ Urea + ⅓ Nano-N] – T3	102.21^a	71.04^a	1.65^a	33.96^b	16.6^a	0.788^a	11.07^a	1.50^c
50% N replacement [⅓ Urea + (½ Urea + ½ Nano-N) + ⅓ Nano-N] – T4	100.47^ab	69.73^ab	1.62^ab	33.7^c	16.31^ab	0.789^a	11.03^a	1.49^c
66% N replacement [⅓Urea + ⅓ Nano-N + ⅓ Nano-N] – T5	99.5^b	68.89^b	1.6^b	33.34^c	16.17^b	0.777^a	10.92^a	1.49^c
100% N replacement [⅓ Nano-N + ⅓ Nano-N + ⅓ Nano-N] – T6	87.64^c	59.87^c	1.44^c	27.83^d	13.78^c	0.645^b	7.06^b	1.96^b
LSD (P = 0.05)	1.63	0.91	0.025	0.595	0.275	0.031	0.261	0.053
LSD (P = 0.05) S × N	2.14	1.20	0.037	NS	0.296	0.036	0.308	NS
LSD (P = 0.05) V× N	1.75	0.98	0.03	0.841	0.242	NS	0.251	0.065
LSD (P = 0.05) V× S	1.24	0.69	0.021	0.595	0.171	NS	0.178	0.046
LSD (P = 0.05) V× S × N	3.03	1.70	0.052	NS	0.419	NS	0.435	0.113
^{Means followed by at least one letter common are not statistically significant (p<0.05) using LSD test}

Physiological Growth analysis:

Plant growth analysis is a quantitative description of environmental impacts on different traits used to calculate net photosynthetic production. Among these, leaf area (LA), leaf area index (LAI), relative growth rate (RGR), crop growth rate (CGR), and net assimilation rate (NAR) are particularly essential in measuring crop growth and may be an indication of prospective productivity. Leaf area affects the plant development under stress and N-substitutions because it represents light interception capacity of plants. Notably, it was found that treatment T3 (33% N replacement) had highest leaf area/plant of 786.6 cm², followed by T2 (783.7 cm²), T4 (777.5 cm²) and T5 (770.6 cm²), but substituting 100% N with nano-N resulted in reduction of leaf area by 14.06% (Table 3). Both stresses reduced leaf area in comparison to control, but higher reduction (29.9%) was noted in saline conditions than the sodic (17.05%). Between varieties, CSR 30 had higher leaf area/plant of 763.5 cm² than PB 1121 (714.0 cm²).

Table 3

Interactive effect of different nitrogen substitutions on growth traits in rice under salt stress conditions
Treatments/Traits	LA	LAI	RGR	CGR	NAR
Variety (V)
CSR 30	763.5a	3.29	90.8^b	15.94^a	0.227^a
PB 1121	714.0b	3.26	97.3^a	12.63^b	0.221^b
LSD (P = 0.05)	4.74	NS	0.6	0.094	0.005
Soil type (S)
Normal soil	875.8^a	3.89^a	101.7^a	17.21^a	0.233^a
Sodic Soil	726.5^b	3.39^b	92.1^b	13.33^b	0.225^b
Saline Soil	613.9^c	2.85^c	88.4^c	12.31^c	0.214^c
LSD (P = 0.05)	5.81	0.046	0.7	0.115	0.002
Nitrogen treatments (N)
No-Nitrogen – T1	638.0^e	2.67^d	78.9^d	8.85^d	0.201^f
RDN through Urea – T2	783.7^ab	3.65^ab	99.3^a	16.09^a	0.236^b
33% N replacement [⅓ Urea + ⅓ Urea + ⅓ Nano-N] – T3	786.6^a	3.71^a	99.5^a	16.17^a	0.239^a
50% N replacement [⅓ Urea + (½ Urea + ½ Nano-N) + ⅓ Nano-N] – T4	777.5^bc	3.65^ab	99.0^ab	15.9^b	0.232^c
66% N replacement [⅓Urea + ⅓ Nano-N + ⅓ Nano-N] – T5	770.6^c	3.61^b	98.0^b	15.75^b	0.227^d
100% N replacement [⅓ Nano-N + ⅓ Nano-N + ⅓ Nano-N] – T6	676.0^d	2.98^c	89.5^c	12.95^c	0.208^e
LSD (P = 0.05)	8.21	0.064	1.0	0.163	0.003
LSD (P = 0.05) S × N	14.22	0.112	1.80	0.283	0.005
LSD (P = 0.05) V× N	11.61	NS	1.50	0.231	NS
LSD (P = 0.05) V× S	8.21	0.064	1.0	0.163	0.003
LSD (P = 0.05) V× S × N	20.12	0.158	2.50	0.4	NS
^{Means followed by at least one letter common are not statistically significant (p<0.05) using LSD test}

Leaf area index (LAI) is an assimilatory system of any crop and plays an important role in deciding the plant growth and yield. Although no significant differences were seen between the two varieties, but with salt treatments LAI decreased by 12.85% under sodicity and 26.74% under salinity stress. Under different nitrogen scenario, LAI was maximum under T3 followed by T2 and T4 (Table 3). Interaction effects of variety, soil and N-management was also found significant for LAI. RGR denotes the dry weight growth over time in proportion to the initial weight and data on RGR depicted that CSR 30 (90.8 mg g^− 1 day^− 1) had lesser RGR in comparison to PB 1121 (97.3 mg g^− 1 day^− 1). Soil type also had significant effect on RGR which decreased by 9.44% under sodicity and 13.08% under salinity stress. Among different N-management scenario, treatments T2 and T3 were statistical same while reduction was noticed with higher substitution of urea with nano-N. Substituting 100% N through nano-N resulted in loss of 10% RGR (Table 3). Crop growth rate is another important (radiation interception dependant) growth variable that largely depends on the quantity of radiation used and received by the crop. Similar results were also noted for CGR among varieties, soil type and different N-management scenario. Net assimilation rate measures net gain of assimilate per unit of leaf area and time. NAR was higher in CSR 30 (0.227 g m^− 2 day^− 1) than PB 1121 (0.221 g m^− 2 day^− 1). Sodicity and salinity led to declined NAR by 3.43% and 8.16%, respectively in comparison to control conditions (Table 3). Statistically higher NAR was noted for T3 (0.239 g m^− 2 day^− 1) than T2, while other N-treatments showed reduction in NAR.

Yield and Yield attributes:

Yield attributing characters are the resultant of dry matter accumulation by plants, translocation of which towards yield attributes, has direct correlation with the grain yield. A significant impact of different nitrogen substitutions strategies and soil type (saline or sodic) was observed on yield variables such as number of tillers/effective tillers, panicle length (cm), number of grains per panicle, and 1000 grain weight. For the production of grain and the quality of the rice, tillering is a crucial agronomic feature. Number of tillers (NT) and number of effective tillers (NET) were higher in CSR 30 than PB 1121. With sodicity and salinity, 13.56 and 19.45% reduction in NT and 14.24 and 18.18% in NET was observed respectively. Number of tillers was highest in T3 followed by T2 and T4, whereas no significant difference in NETs was noted between T2-T5 (Table 4). Interactive effects of variety x soil x N-management was non-significant for number of tillers and significant for number of effective tillers. Statistically significant differences were found in average panicle length ranging from 8.55–11.13 cm under different N-scenario, whereas rice plants receiving no-nitrogen (T1) had panicle length of 7.53 cm (Table 4). Significant varietal differences were also noted and found CSR 30 had higher average panicle length of 9.87 cm than PB 1121 (9.50 cm).

Table 4

Interactive effect of different nitrogen management practices on yield attributes of rice under salt stress conditions
Treatments/Traits	NT	NET	PL	NG/P	TW
Variety (V)
CSR 30	6.68^a	6.02^a	9.87^a	43.53	24.19^a
PB 1121	6.31^b	5.76^b	9.50^b	42.56	18.54^b
LSD (P = 0.05)	0.129	0.11	0.234	1.56	0.59
Soil type (S)
Normal soil	7.30^a	6.6^a	10.76^a	51.25^a	21.82^a
Sodic Soil	6.31^b	5.66^b	9.67^b	41.64^b	21.54^b
Saline Soil	5.88^c	5.4^c	8.63^c	36.25^c	20.74^c
LSD (P = 0.05)	0.158	0.135	0.287	1.203	0.72
Nitrogen treatments (N)
No-N – T1	4.4^d	3.79^c	7.53^e	27.56^f	17.38^d
RDN through Urea – T2	7.21^ab	6.55^a	10.86^a	51.78^b	22.79^ab
33% N replacement [⅓ Urea + ⅓ Urea + ⅓ Nano-N] – T3	7.31^a	6.58^a	11.13^a	53.67^a	23.41^a
50% N replacement [⅓ Urea + (½ Urea + ½ Nano-N) + ⅓ Nano-N] – T4	7.15^ab	6.47^a	10.30^b	47.5^c	22.60^ab
66% N replacement [⅓Urea + ⅓ Nano-N + ⅓ Nano-N] – T5	7.06^b	6.45^a	9.78^c	42.94^d	22.10^ab
100% N replacement [⅓ Nano-N + ⅓ Nano-N + ⅓ Nano-N] – T6	5.91^c	5.47^b	8.55^d	34.83^e	19.78^c
LSD (P = 0.05)	0.224	0.19	0.405	1.701	1.02
LSD (P = 0.05) S × N	NS	NS	NS	NS	1.76
LSD (P = 0.05) V× N	0.317	0.269	NS	2.406	1.44
LSD (P = 0.05) V× S	0.224	0.19	0.405	1.701	1.02
LSD (P = 0.05) V× S × N	NS	0.466	NS	NS	2.49
^{Means followed by at least one letter common are not statistically significant (p<0.05) using LSD test}
^{NT−no of tillers; NET−no of effective tillers; PL− panicle length; NG/P− no of grains/panicle; TW−test weight}

The panicle length was reduced by 10.13% and 19.8% under sodicity and salinity stress, respectively. The reciprocal effect of panicle length was seen on number of grains/panicle (NG/P) (Table 4). Statistically, higher number of average grains per panicle were found in T3 (53.67) than T2 (51.78). Test weight (1000 seed weight) was also significant among varieties, CSR 30 had higher test weight (24.19g) than PB 1121 (18.54g). Among different N-scenario, treatment T3 (33% replacement of nitrogen through nano-N) had higher test weight (23.41 g) followed by T2 (22.6 g) and T4 (22.1 g), which were statistical at par (Table 4). Although we observed grain yields of 12.26 g/plant in CSR 30 Basmati and 11.75 g/plant in PB 1121 under normal soil with RDN, reducing to 9.66 and 8.55 g/plant in CSR 30 Basmati and 9.87 and 8.57 g/plant in PB 1121 under sodic and saline soils, respectively. Replacing nitrogen source through nano-N resulted in yield improvement under T3 only i.e. 33% replacement of urea through nano-N enhanced grain yield by 2.04 & 1.79% under normal soil, 1.45% & 2.23% under sodic soil, 6.43% & 1.4% under saline soil in CSR 30 and Pusa 1121, respectively. The grain yield was less in treatments T4 and T5 but these were at par with RDN through urea. The interactive effect of different nitrogen management practices on grain and biological yield of rice are shown in Fig. 1. Replacing 100% N (basal or seed priming) through nano-N (T6) didn`t match the grain productivity with RDN suggesting the need of basal N application through urea only. Similar trend was obtained for the biological yield.

Briefly, we can summarize that treatment T3, replacing 33% nitrogen through nano-N showed superiority in terms of maintaining plant growth attributes, physiological traits, yield and yield attributes over 100% nitrogen through urea in rice. Beyond 33% replacement, the performance of plant in terms of various morpho-physiological traits showed decreasing pattern limiting crop yield.

The delivery of critical nutrients for plants through basal and foliar application at various growth stages is necessary. Foliar application is also equally effective for particular nutrient because of quick absorption and appropriate concentration [18–20]. Nitrogen is the main building block of plant protoplasm and for appropriate plant growth and development, nitrogen is the most important nutrient being a source of amino acids, proteins, nucleotides and nucleic acids, leaf chlorophyll and enzymes etc. Although nitrogen remains in the mobile phase between plant and soil yet it is the most limiting element also. Therefore, efficient application of nitrogen and its uptake by the plants is vital for improving crop growth and yield. With depleting natural resources, percent substitution of urea application with nano-nitrogen is considered one of the most promising alternatives for agriculture systems. In present experiment, we also planned to explore the potential of Nano-Nitrogen on crop growth factors in saline and sodic/alkaline stress conditions in rice varieties. This might be the first report of Nano-N application on plant growth and development under abiotic stress condition although very few reports are available for use of nano-N in normal soil conditions. Two types of basmati rice varieties, CSR 30 and PB 1121, were grown in saline and sodic soils, and a substantial effect of nano-nitrogen was observed on plant growth metrics by substituting traditional urea by 33%, 50%, 66% and 100% application doses. Nano fertilizers have a faster and higher absorption level by plants due to their small size, quick diffusion rates, and slow release of nutrients than their traditional counterparts, which results in superior plant development, growth and plant biomass [21–22]. This nano-nitrogen easily enters the plant cell through stomata and other membrane pores, gets distributed in the plant cell and is further assimilated in routine plant cell process.

In both saline and sodic soils, CSR 30 is more responsive to fertilizers with taller plants than PB 1121, however replacing urea with nano-N had no significant effect on plant height. Plant height and relative leaf water content increased with application of Nano-N up to 33% replacement but with further replacement these traits decreased (Table 2). Similar results obtained by Singh et al. [23] reported better plant height with 75% NPK and combined nano nutrients of N, P, K, Zn in wheat under controlled conditions. Similarly, an increase in plant height with application of NPK with nano-nutrient (NPK) has been reported by Mehta [24], with nano-Zn by Munir et al. [25]. This may be due to the foliar absorption of nano-fertilizers which gets stored in the cell and used slowly for plant growth. In our studies also, we observed salt stress induced reduction in the plant height is compensated with application of nano-urea with 33%, 50% and 60% replacement of conventional urea although alone nano-urea is not effective and reduced plant growth parameters (Table 2) were seen. Since stress tends to accumulate other toxic ions and probably, nano-N tends to maintain the ionic homeostasis as well to counter-act the harmful ions, imparting the plant cell favorable cellular mechanisms. Rizwan et al. [26] have also reported the enhanced effect of Zn and Fe nano-fertilizers on plant height, spike length, root-shoot fresh and dry weights and grain weight in wheat. A significant increase was also observed in rate of photosynthesis, stomatal conductance and other gas-exchange attributes of rice plants in both saline-sodic soils with 33% urea replacement with nano-N (Table 2). Application of nano-urea in all combinations with conventional urea (T3, T4 and T5) increased the gas-exchange attributes but lower than the control plants (receiving 100% N through Urea). The foliar application of Nano-N, makes more nitrogen available inside the cell which accelerated the growth of leaves by the production of proteins necessary for cell development, cell division as well as chlorophyll synthesis and photosynthesis. Nitrogen is an essential component of chlorophyll, so the foliar supplementation maintains the chlorophyll structure and content under salt stress, and hence the photosynthetic rate leading to better plant growth. While nitrogen is not required for photosynthesis to occur, it is essential for the plant to be able to create the energy it needs to power this process. There is a widely recognized relationship between light-saturated photosynthetic rate and the nitrogen content of the leaves because nitrogen forms an important ingredient of the proteins that are responsible for carrying out the essential photochemical and biosynthetic reactions of photosynthesis. Light generates energy, which is used by plants to create energy, and nitrogen must be present in order for leaves to remain green. When nitrogen is not available, plants cannot reproduce or grow. The synergistic effect of nano fertilizers alongwith chemical fertilizer leads to greater photosynthates accumulation and translocation to the plant's economic parts, resulting in high yield, mainly credited to increased source and sink strength through uniform distribution of nano-N through phloem [27]. Crops provided with the exact amounts of nutrients (controlled release through nano-fertilizer) in the right proportions helps in reducing stomatal resistance and increasing stomatal conductivity, providing the plant with adequate carbon dioxide and water to continue photosynthesis and remove nutrients from the soil which ultimately resulted in increased yield [28–30]. Similarly, Di et al. [31] also noted that CuO-NPs exposure notably increased the biomass, root length, and root tip number by 22.0%, 22.7%, and 82.9%, respectively, whereas Cu- NPs and CuSO₄ significantly reduced root biomass, net photosynthetic rate (PN), and root length by 31.2% and 44.2%, 24.5% and 32.2%, and 43.4% and 40.6%, respectively in bok choy (Brassica chinensis L.) under hydroponic conditions. Similarly, in maize (Zea mays L.) nano carbon synergistically improved plant growth through better absorption and utilization of N [32]. In rice also, rice performance was improved with nano-N through better NUE [30].

Although salinity overall decreased the photosystem traits like Pn, gS, E and WUE (Table 2). This may be due to presence of toxic Na⁺ ions in the transpirational stream causing photo-inhibition and thus, stomatal opening. Na⁺ accumulation within chloroplast causes reduction/denaturation of photosynthetic pigments, high salinity impairs photosynthetic efficiency by lowering the electron transport rate (ETR) and quantum yield of photosystem II [33, 34]. Osmotic stress, higher ion accumulation in the photosynthesis apparatus, causes physiological drought at the cellular level, resulting in an indirect reduction in the photosynthetic rate [35–37]. Furthermore, under salt stress due to a lack of fully functional osmoregulation and lower K⁺ uptake, the incapability of guard cells leads to stomatal closure, which directly reduces the photosynthetic activity [38, 39]. Various researchers predicted that use of nano materials combat the consequences of salinity and assist the plant to improve under stress conditions. Faizan et al. [40] reported substantial improvement in fluorescence, chloroplast structures, and photosynthesis-related parameters in response to ZnO-NPs in rice. The rate of photosynthesis under saline stress is being promoted by application of ZnO-NPs by stabilizing the photosynthetic apparatus through reducing the physiochemical damage, enhancing the biosynthesis of photosynthetic pigments, and neutralizing the ionic toxicity. In our studies also, maximum leaf greenness was observed with application of RDN through urea which decreased under salt stress (Table 2). With spray of nano-N replacing 33, 50, 66% urea, significant enrichment of green pigment was noted in rice leaves but again lower than the plant leaves without stress. Nano-formulation provided the required nutrient with long lasting and slow release at target site and this might be the reason for improving chlorophyll status in plants under stress. Salinity causes photo-degradation of light harvesting compound and reduction in chlorophyll synthesis along with membrane instability. Almost all the plants are capable of osmoregulation through biosynthesis of compatible osmolytes at the cost of 10 times energy demand which gets more with increasing stress type. The exogenous application of nano-N might ameliorate salinity-induced effects to some extent with continuous nitrogen supply, an integral part of proteins, thus, maintaining cell stability. While studying the effect of different combinations of nano-N with traditional urea in mustard, an increased leaf area index and SPAD have been reported, 50% at par with control [41]. Salinity of 120 mM NaCl significantly affected plant growth attributes, physiological performance, nutrient profiles, antioxidant activity, plant yield, and yield-contributing characteristics of maize plants. Foliar application of ZnO-NPs successfully alleviated these salinity effects on LGR, PGR etc and significantly improved all studied parameters, except transpiration rate (TR) and intrinsic water use efficiency (iWUE) [42]. Foliar spray of iron source has also shown enhanced SPAD values, chlorophyll content in addition to maintaining the membrane stability in groundnut cultivars under iron deficiency [43] depicting the targeted delivery and beneficial effects of foliar nutrients.

The relative growth rate (RGR) and crop growth rate (CGR) declined in rice under both saline and sodic soils (Table 3) which was significantly improved by foliar spray of Nano-N at all three levels, i.e., 30,50 & 66% replacements (T3, T4 and T5). RGR and CGR were at par with application of RDN-urea (T2) and 33% replacement with nano-N (T3). Similarly, the net assimilation rate (NAR) decreased with salt stress which was further improved by application of nano-N in all three combinations (T3-T5) although 33% replacement was observed as an effective source of nitrogen in stress conditions. Since nano fertilizers provided higher absorption area with greater diffusion rates for various metabolic processes, resulting in increased size and efficiency of source, which in turn have resulted in higher yield attributes and grain yield [44]. Manikandan and Subramanian [45] studied the effect of zeolite based N fertilizers in maize and found that the application of urea in the form of nanozeo urea recorded significantly higher grain yield (156 g), 100 seed weight (29.4 g) and crude protein (4.7%) that might be due to the effect of slow release and controlled release of nitrogen from the nanozeo-urea application and availability of nitrogen throughout crop growth period. We have also observed rice plants receiving 33% nano-N in combination with urea gaining statistical at par/higher yield and yield attributes than RDN (Table 4; Fig. 1). The improvement in yield characteristics with strategic application of nano-urea might be brought by effective nutrient intake (higher absorption of nutrient and their deep penetration into leaves) and metabolic output via application of nano fertilizer. This also provides enough time to plants to perform its nutritional efficiency and growth more effectively than reflected [30, 46]. Al-Juthery et al. [47] also revealed a significantly enhanced wheat plant height, 1000-grain weight, grains, straw and biological yields with foliar application of nano fertilizer. A 15–20% increased crop yield has been reported with foliar spray of nano-N in rice [46], sweet corn [48], maize [49], rice [50] and wheat [51]. Such increased crop yield with nano-fertilizer might be due to an increase in the number of filled grains in panicle at the expense of empty grains because of necessary elemental composition and high efficiency of nanoparticles. In summary, we can propose that the nano-nitrogen through foliar application is being absorbed and stored by plant cells which are further used by the photosynthetic machinery improving relative plant growth rate, crop growth rate and net assimilation rate. These factors cumulatively enhance the effective tillers and hence, grain yield under salt stress conditions. Briefly, we can summarize that the effects of nitrogen substitutions through nano-N can benefit plants in terms of better plant performance and yield gains through synergistic nutrient release and availability, although the recommended dose of fertilizers is must as initial source of nutrients.

The plant nutrients have been used in several ways for increasing crop productivity with basal or fertigation or foliar spray or a combination of all three ways. Foliar application of plant nutrients is more advantageous than soil application with better efficiency and also assistance in physiological stresses. Although, stress environments created ionic imbalance and cellular damage, thereby, lowering the total chlorophyll content and rate of photosynthesis, resulting in a significant reduction in growth and physiological attributes and hence, lowered yield. But, application of nano-N alleviated the harmful effects of salt stress with best efficacy at 33% replacement than 50 or 66% replacements and was at par with the recommended dose of nitrogen in form of urea. The foliar dose of nano-N makes nitrogen available for more time for the plants as source of nutritional factors. Additionally, it does not get washed away unlike the traditional soil fertilizers, thus, saving the raw resources as well. Most importantly, substituting 33% nitrogen through nano-N resulted in enhancement of plant growth traits, through better physiological and yield attributes contributing to enhanced yield in comparison to the RDN through urea. Based on these brief findings, we can conclude that application of nano-fertilizers with controlled release of target elements alongwith conventional fertilizer may be a prospective solution for minimizing soil contamination, improving soil health and agronomic productivity along with reducing impact of abiotic stresses in plants. These experimental findings are based on pot culture studying the plant physiological performance, the actual economic values of using nano-nitrogen than urea requires field studies on larger scales.

Ethics approval and consent to participate - Not applicable

Consent for publication - Not applicable

Availability of data and materials- All data generated or analysed during this study are included in this published article.

Competing interests - The authors declare no competing interests.

Funding- We would like to thank the Indian Farmers Fertilizer Cooperative Ltd (IFFCO), Chandigarh, Haryana for financial support for this experiment.

Authors' contributions- Conceptualization of the experiments was done by AK, PS AKB, and AM. Plant samplings and data analysis, and writing the original draft were done by NK, SD, MR, KM. ArK and AKB helped in various analyses and PS, AK, AM, reviewed and edited the manuscript. All authors contributed to the writing of the manuscript and reviewed the draft. All authors approved the final manuscript.

Acknowledgements

The authors acknowledge the Director, ICAR-Central Soil Salinity Research Institute (CSSRI) for proving all support to carry out the experiments. The authors also acknowledge the support of the staff in Plant Physiology, Soil Fertility Laboratories at CSSRI in collecting experimental data and analyzing all samples.

Corresponding authors

Anita Mann; Parvender Sheoran; Ashwani Kumar

Food and Agriculture Organisation of the United Nations. How to Feed the World in 2050. http://www.fao.org/fileadmin/templates/wsfs/docs/expert_paper/How_to_Feed_ the_World_in_2050.pdf accessed 13/09/17, 2009.
Mitchell CH, Richard GS, Meagan ES, Lesley WA, David AM. Agriculture in 2050: Recalibrating Targets for Sustainable Intensification. Bioscience. 2017;67(4):386–91.
Ladha JK, Kumar V, Alam MM, Sharma S, Gathala M, Chandna P, Saharawat YS, Balasubramanian V. Integrating crop and resource management technologies for enhanced productivity, profitability, and sustainability of the rice-wheat system in South Asia. In: Ladha JK, Singh Y, Erenstein O, Hardy B, editors. Integrated crop and resource management in the rice-wheat system of South Asia. Los Baños: International Rice Research Institute; 2009. pp. 69–108.
Prasad R. Rice-Wheat Cropping Systems. Advan Agron. 2005;86:255–339.
Sheoran P, Kamboj P, Kumar A, Kumar A, Singh RK, Barman A, Prajapat K, Mandal S, Yousuf DJ, Narjary B, Kumar S. Matching N supply for yield maximization in salt-affected wheat agri-food systems: On-farm participatory assessment and validation. Sci Total Environ. 2023;875:162573.
Barker VA, Pilbeam JD. Handbook of Plant Nutrition. Boca Raton, FL: CRC Press, Taylor and Francis Group; 2007.
Liu CW, Sung Y, Chen BC, Lai HY. Effects of nitrogen fertilizers on the growth and nitrate content of lettuce (Lactuca sativa L). Internat J Environ Res Pub Health. 2014;11(4):4427–40.
Lorenzo H, Siverio J, Caballero M. Salinity and nitrogen fertilization and nitrogen metabolism in rose plants. J Agri Sci. 2001;137(1):77–84.
Fernandez V, Brown PH. From plant surface to plant metabolism: The uncertain fate of foliar-applied nutrients. Front Plant Sci. 2013;4:289.
Raimondi G, Maucieri C, Toffanin A, Renella G, Borin M. Smart fertilizers: What should we mean and where should we go? Italian J Agron. 2021; 16(2).
Raliya R, Saharan V, Dimkpa C, Biswas P. Nanofertilizer for precision and sustainable agriculture: Current state and future perspectives. J Agri Food Chem. 2017;66:6487–503.
Meghana KT, Wahiduzzaman MD, Golla V. Nanofertilizers in Agriculture. Acta Sci Agri. 2021;5:35–46.
Verma KK, Song XP, Joshi A, Tian DD, Rajput VD, Singh M, Arora J, Minkina T, Li YR. Recent Trends in Nano-Fertilizers for Sustainable Agriculture under Climate Change for Global Food Security. Nanomat. 2022;12:173.
Bhardwaj AK, Arya G, Kumar R, Hamed L, Pirasteh-Anosheh H, Jasrotia P, Kashyap PL, Singh GP. Switching to nano-nutrients for sustaining agro-ecosystems and environment: the challenges and benefits in moving up from ionic to particle feeding. J Nanobiotech. 2022;20:19.
Arnon DI. Copper enzymes in isolated chloroplasts polyphenoloxidase in Beta vulgaris. Plant Physiol. 1949; 24(1).
Barrs HD, Weatherley PE. A re-examination of the relative turgidity technique for estimating water deficits in leaves. Australian J Biol Sci. 1962;15:413–28.
Kumar A, Mishra AK, Singh K, Lata C, Kumar A, Krishnamurty SL, Kumar P. Diurnal changes and effect of elevated CO₂ on gas exchange under individual and interactive salt and water stress in wheat (Triticum aestivum). Indian J Agric Sci. 2019;89(5):763–8.
Subramanian KS, Sharmila RC. Synthesis of nano-fertilizers formulations for balanced nutrition. In: Proc Indian Soc Soil Sci-Platinum Jubilee Celebration, 22–25 December, IARI Campus, New Delhi, 2009; p 85.
El-Saadony MT, ALmoshadak AS, Shafi ME, Albaqami NM, Saad AM, El-Tahan AM, Desoky EM, Elnahal ASM, Almakas A, Abd El-Mageed TA, Taha AE, Elrys AS, Helmy AM. Vital roles of sustainable nano-fertilizers in improving plant quality and quantity-an updated review. Saudi J Biol Sci. 2021;28(12):7349–59.
Salama DM, Abd El-Aziz ME, Shaaban EA, Osman SA, El-Wahed MSA. The impact of nanofertilizer on agro-morphological criteria, yield, and genomic stability of common bean (Phaseolus vulgaris L). Sci Rep. 2022;12:18552.
Yuvaraj M, Subramanian K. Development of slow release Zn fertilizer using nano-zeolite as carrier. J Plant Nut. 2018;41(3):311–20.
Alhasan AS, Al-Ameri DT, Jawad AH, Talib QJ. Effect of foliar application of NPK nano-fertilizer on some agronomic traits and essential oil of sweet basil (Ocimum Basilicum L.) grown under the shade-net house conditions. Nat Vol Essen Oils. 2021;8(6):2018–24.
Singh BV, Singh S, Verma S, Yadav SK, Mishra J, Mohapatra S, Gupta SP. Effect of Nano-nutrient on Growth Attributes, Yield, Zn Content, and Uptake in Wheat (Triticum aestivum L). Internat J Environ Clim Change. 2022;12(11):2028–36.
Mehta S. Effect of integrated use of Nano and non-nano-fertilizers on quality and productivity of wheat (Triticum aestivum L.) ([doctoral dissertation] Sher-E-Kashmir University of Agricultural Sciences and Technology of Jammu, 2017.
Munir T, Latif M, Mahmood A, Malik A, Shafiq F. Influence of IP-injected ZnO nanoparticles in Catla catla fish: hematological and serological profile. Naunyn-Schmiedebergs Arch Pharmacol. 2020;393:2453–61.
Rizwan M, Ali S, Ali B, Adrees M, Arshad M, Hussain A, Zia Ur Rehman M, Waris AA. Zinc and iron oxide nanoparticles improved the plant growth and reduced the oxidative stress and cadmium concentration in wheat. Chemosphere. 2019;214:269–77.
Rajput JS, Thakur AK, Nag NK, Chandrakar T, Singh DP. Effect of nano fertilizer in relation to growth, yield and economics of little millet (Panicum sumatrense roth) under rainfed conditions. Pharma Innov J. 2022;11(7):153–6.
DeRosa MC, Monreal C, Schnitzer M, Walsh R, Sultan Y. Nanotechnology in fertilizers. Nat Nanotech. 2010;5:91–4.
Al-Juthery HW, Al-Fadhly JT, Ali EAHM, Al-Taee RAHG. Role of some nanofertilizers and atonikin maximizing for production of hydroponically-grown barley fodder. Internat J Agri Stat Sci. 2019;15:565–70.
Velmurugan A, Subramani T, Bommayasamy N, Ramakrishna, Kumar M, Swarnam TP. The effect of foliar application of nano urea (liquid) on rice (Oryza sativa L). J Andaman Sci Asso. 2021;26(2):76–81.
Di X, Fu Y, Huang Q, Xu Y, Zheng S, Sun Y. Comparative effects of copper nanoparticles and copper oxide nanoparticles on physiological characteristics and mineral element accumulation in Brassica chinensis L. Plant Physiol Biochem. 2023;196:974981.
Shumin L, Chen M, Lihe L, Aiyuan Z, Xiaoguang H, Fei W, et al. Effect of Nano-carbon on nitrogen absorption, root activity and soil enzyme of maize. J Northeast Agri Univ. 2014;45(07):14–25.
Yue J, Fu Z, Zhang L, Zhang Z, Zhang J. The positive effect of different 24-epiBL pretreatments on salinity tolerance in Robinia pseudoacacia L. seedlings. Forests. 2018;10:4.
Yang Z, Li JL, Liu LN, Xie Q, Sui N. Photosynthetic regulation under salt stress and salt-tolerance mechanism of sweet sorghum. Front Plant Sci. 2020;10:1722.
Acosta-Motos JR, Ortuño MF, Bernal-Vicente A, Diaz-Vivancos P, Sanchez-Blanco MJ, Hernandez JA. Plant responses to salt stress: Adaptive mechanisms. Agron. 2017;7:18.
Dhansu P, Kumar R, Kumar A, Vengavasi K, Raja AK, Vasantha S, Meena MR, Kulshreshtha N, Pandey SK. Differential Physiological Traits, Ion Homeostasis and Cane Yield of Sub-Tropical Sugarcane Varieties in Response to Long-Term Salinity Stress. Sustain.2022;14:13246.
Kumar A, Sheoran P, Mann A, Yadav D, Kumar A, Devi S, Kumar N, Dhansu P, Sharma DK. Deciphering trait associated morpho-physiological responses in Pearl millet hybrids and inbred lines under salt stress. Front Plant Sci. 2023;14:1121805.
Yun P, Xu L, Wang SS, Shabala L, Shabala S, Zhang WY. Piriformospora indica improves salinity stress tolerance in Zea mays L. plants by regulating Na⁺ and K⁺ loading in root and allocating K⁺ in shoot. Plant Growth Regu. 2018;86:323–31.
Kumar A, Lata C, Kumar P, Devi R, Singh K, Krishnamurthy SL, Kulshreshtha N, Yadav RK, Sharma SK. Salinity and drought induced changes in gas exchange attributes and chlorophyll fluorescence characteristics of rice (Oryza sativa) varieties. Indian J Agri Sci. 2016b;86(6):718–26.
Faizan M, Bhat JA, Hessini K, Yu F, Ahmad P. Zinc oxide nanoparticles alleviates the adverse effects of cadmium stress on Oryza sativa via modulation of the photosynthesis and antioxidant defense system. Ecotox Environ Saf. 2021;220:112401.
Navya K, Sai Kumar R, Krishna Chaitanya A, Sampath O. Effect of Nano Nitrogen in Conjunction with Urea on Growth and Yield of Mustard (Brassica juncea L.) in Northern Telangana Zone. Biol Forum - Internat J. 2022;14:95–9.
Seleiman MF, Ahmad A, Alhammad BA, Tola E. Exogenous Application of Zinc Oxide Nanoparticles Improved Antioxidants, Photosynthetic, and Yield Traits in Salt-Stressed Maize. Agron. 2023;13:2645.
Mann A, Singh AL, Oza S, Goswami N, Mehta D, Chaudhari V. Effect of iron source on iron deficiency induced chlorosis in groundnut. Legume Research-An Int J. 2017;40(2):241–9.
Davarpanah S, Tehranifar A, Davarynejad G, Aran M, Abadía J, Khorassani R. Effects of Foliar Nano-nitrogen and Urea Fertilizers on the Physical and Chemical Properties of Pomegranate (Punica granatum cv. Ardestani). Fruits Hort Sci. 2017;52(2):288–94.
Manikandan A, Subramanian KS. Evaluation of zeolite based nitrogen nanofertilizers on maize growth, yield and quality on inceptisols and alfisols. Internat J Plant Soil Sci. 2016;9:1–9.
Jassim R, Hanoon AH, Kadhem N, Ghanim BN. Impact of levels and time of foliar application of nano fertilizer (Super micro plus) on some components of growth and yield of Rice (Oriza Sativa L). J Plant Arch. 2019a;19(1):1279–83.
Al-Juthery HWA, Habeeb KH, Altaee FJK, AL-Taey DKA, Al-Tawaha ARM. Effect of foliar application of different sources of nano-fertilizers on growth and yield of wheat. Biosci Res. 2018;15:3988–97.
Sarwar I, Gedam VB, Gajbhiye PN, Bhosale AS, Deshmukh DP. Effect of Nano Nitrogen on Productivity of Sweet Corn (Zea mays Saccharata) and Soil Fertility in Sub-montane Zone of Maharashtra, India. Biol Forum - Int J. 2021;13(3b):246–50.
Samui S, et al. Growth and productivity of rabi maize as influenced by foliar application of urea and nano-urea. Crop Res. 2022;57(3):136–40.
Singh PP, Priyam A, Singh J, Gupta N. Biologically synthesised urea-based nanomaterial shows enhanced agronomic benefits in maize and rice crops during Kharif season. Scientia Hort, 315,2023,111988,.
Kumar N, Tripathi SC, Yadav DB, et al. Boosting wheat yield, profitability and NUE with prilled and nano urea in conservation tillage. Sci Rep. 2023;13:18073.

No competing interests reported.

Download PDF

Journal Publication

published 30 Sep, 2024

Read the published version in BMC Plant Biology →

Editorial decision: Revision requested
22 Apr, 2024
Reviews received at journal
20 Apr, 2024
Reviewers agreed at journal
20 Apr, 2024
Reviews received at journal
07 Apr, 2024
Reviewers agreed at journal
29 Mar, 2024
Reviewers agreed at journal
13 Mar, 2024
Reviewers invited by journal
13 Mar, 2024
Editor assigned by journal
07 Mar, 2024
Submission checks completed at journal
07 Mar, 2024
First submitted to journal
05 Mar, 2024

You are reading this latest preprint version

Elucidating morphogenic and physiological traits of rice with nitrogen substitution through nano-nitrogen under salt stress conditions

Status:

Journal Publication

Version 1

Abstract

Background

Results

Conclusions

Figures

Background

Methods

Results

Morpho-physiological traits:

Gas exchange attributes:

Physiological Growth analysis:

Yield and Yield attributes:

Discussion

Conclusions

Declarations

References

Additional Declarations

Status:

Journal Publication

Version 1