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Plants are frequently exposed to adverse environments during their life span. Among them drought stress is one of the major threats to agricultural productivity. In order to survive in such unstable environment, plants have developed mechanisms through which they recognize the severity of the stress based on the incoming environmental stimuli. To combat the detrimental effects of drought, the plants have evolved various strategies to modulate their physio-hormonal attributes. These strategies that can be modulated by shade and microbes contribute to enhancing tolerance to drought and reducing yield loss. Plant hormones, such as abscisic acid, auxin and ethylene have a major role in the shade- and microbe-associated improvement of drought tolerance through their effects on various metabolic pathways. In this process, the CLAVATA3/EMBRYOSURROUNDING REGION-RELATED 25 peptide has a major role due to its effect on ABA synthesis as shown in our regulatory model.

A field experiment was conducted in 2018–2020 to investigate the effect of two nitrogen application rates (N0 = 0 kg ha−1(control), N90 = 90 kg ha−1, and N180 = 180 kg ha−1) on morphological and physiological behaviours of two new rapeseed varieties; V1 = JYJS01 (semi-dwarf variety) and V2 = CY36 (tall variety). Our results indicated that N application enhanced the plant growth and seed protein content in comparison to control. Contrastingly, compared with control, sugar contents, i.e. sucrose and reducing sugars, decreased significantly in response to an increase in N. Seed oil content also decreased by 8.5% and 5.5%, 6.7% and 3.9% against N180 in V1 and V2 during 2019 and 2020, respectively. Furthermore, higher nitrogen application rates decreased seed fatty acid proportions by decreasing the sugar availability for fatty acid biosynthesis. Our results demonstrated the highest seed yield (9.4 g plant−1 in 2018/19 and 9.5 g plant−1 in 2019/20) in V2 against N180, and the lowest seed yield (3.2 g plant−1 in 2018/19 and 3.4 g plant−1 in 2019/20) in V1 at control. These findings imply that a high nitrogen application rate had increased the yield. At the same time, the carbohydrates translocation from stems to seed for fatty acid biosynthesis decreased, which played their significant role in seed physiology for fatty acid metabolisms, ultimately affected the seed quality. However, there is still a dire need to evaluate how nitrogen application affect the carbohydrate availability for fatty acid metabolism in the seed of new winter rapeseed varieties.

In maize-soybean intercropping system, shade is the major chronic restrain that effected the normal growth of soybean. Different spatial patterns of this system have affected the microclimate of soybean by shading of maize plants. However, the negative impacts of shading stress can be mitigated by providing the optimal ratios of different fertilizers. Therefore, to test this hypothesis, the soybean plants were grown under different light conditions (normal light and shade) to evaluate the response to varying NH4 + /NO3 - ratios. The seed of soybean (Glycine max L. cultivar of "Nan-99-6") were grown in nutrient solution at a total concentration of 5mM N using different NH4 + /NO3 - ratios (To= 0:0, T1= 0:100, T2= 25:75, T3=50:50, and T4= 75:25) for 40 days in greenhouse at PPFD 320.95 μmolm-2 s-1 (low light intensity) and 967.53 μmolm-2 s-1 (normal light intensity). Under low light the growth and photosynthesis of soybean seedlings had significantly decreased as compared to normal light conditions. Nonetheless, the optimal ratios of NH4 + /NO3 - had improved the growth and photosynthesis activities of soybean seedlings under both light conditions. Our results indicated that soybean seedlings supplied with optimal NH4 + /NO3 - ratios (25:75 and 50:50) have showed the maximum biomass yield, chlorophyll pigments, leaf gas exchange, photochemical activities and root growth as compared to high NH4 + /NO3 - ratios (T1 and T4). Since, the higher ratios of NH4 + /NO3 - resulted in lower plant growth due to accumulation in plant tissues; therefore, we suggested that optimal ratios of NH4 + /NO3 - can enhance the shade resistance of soybean seedlings.

BACKGROUND AND OBJECTIVE For cultivation and high yield of oilseed rape (Brassica napus L.) in China, traditional seedling transplanting is replaced by seed-sowing but, better nitrogen management is crucial and not established yet. This study aimed to adapt N management to the seed-sowing method for the winter oilseed rape and to minimize the N fertilizer-derived pollution potential in the upper reaches of Yangtze River Basin. MATERIALS AND METHODS Three field experiments were conducted to check effect of different doses of N fertilizers, split doses of N and different types of N fertilizers for seed-sowing winter oilseed rape with high plant density in upper reaches of Yangtze River Basin in Sichuan province of China. RESULTS In first experiment, among four doses (0, 90, 180 and 270 kg N ha-1) on average 3.54 t ha-1 was in 180 kg N ha-1 and 3.61 t ha-1 in 270 kg N ha-1 while cultivars dy6 and cn3 produced 3.23 and 3.29 t ha-1 which is significantly higher than zs11. There was no significant difference in N-use efficiency among three cultivars tested and second experiment showed no significant difference in seed yield with split N application. The third experiment compared the effects of different fertilizer types (urea, coated urea, 1:1 mixture of urea and coated urea and compound nitrogen fertilizer) on seed yield and get no significant difference in seed yield. CONCLUSION This experiment proved that seed sowing method with higher nitrogen had high yield in the upper reaches of Yangtze River Basin in China, but higher N application may cause environment pollution. So, seed sowing method with nitrogen 180 kg N ha-1 was proved to be more effective.