Plant Leaf Area Research Articles

The use of biostimulants as a key to sustainable hydroponic lettuce farming under saline water stress

BackroundThe utilization of high-quality water in agriculture is increasingly constrained by climate change, affecting availability, quality, and distribution due to altered precipitation patterns, increased evaporation, extreme weather events, and rising salinity levels. Salinity significantly challenges salt-sensitive vegetables like lettuce, particularly in a greenhouse. Hydroponics water quality ensures nutrient solution stability, enhances nutrient uptake, prevents contamination, regulates pH and electrical conductivity, and maintains system components. This study aimed to mitigate salt-induced damage in lettuce grown via the floating culture method under 50 mM NaCl salinity by applying biostimulants.ResultsWe examined lettuce’s physiological, biochemical, and agronomical responses to salt stress after applying biostimulants such as amino acids, arbuscular mycorrhizal fungi, plant growth-promoting rhizobacteria (PGPR), fulvic acid, and chitosan. The experiment was conducted in a greenhouse with a randomized complete block design, and each treatment was replicated four times. Biostimulant applications alleviated salt’s detrimental effects on plant weight, height, leaf number, and leaf area. Yield increases under 50 mM NaCl were 75%, 51%, 31%, 34%, and 33% using vermicompost, PGPR, fulvic acid, amino acid, and chitosan, respectively. Biostimulants improved stomatal conductance (58–189%), chlorophyll content (4–10%), nutrient uptake (15–109%), and water status (9–107%). They also reduced MDA content by 26–42%. PGPR (1.0 ml L‒1), vermicompost (2 ml L‒1), and fulvic acid (40 mg L‒1) were particularly effective, enhancing growth, yield, phenol, and mineral content while reducing nitrate levels under saline conditions.ConclusionsBiostimulants activated antioxidative defense systems, offering a sustainable, cost-effective solution for mitigating salt stress in hydroponic lettuce cultivation.

Impact of Bioagents on Growth and Yield Parameters of Root-knot Nematode Infested Mulberry Plants

Mulberry (Morus alba L.) is a vital crop for sericulture and its productivity is crucial for the industry's sustainability. This study investigated the influence of bioagents viz., Purpureocillium lilacinum, Trichoderma harzianum, Trichoderma viride, Pochonia clamydosporia and Pseudomonas fluorescens, alongside control treatments including carbofuran 3G and neem cake on growth and yield parameters in severely root-knot nematode infested mulberry plants. The treatments involved are generally recommended to manage root-knot nematode infestation. The results revealed that T. viride @ 5 kg/ha significantly improved plant growth, leaf area and leaf yield leading to enhanced productivity. The findings of this study underscore the potential of bioagents in fostering environmentally sustainable and economically viable sericulture. Aims: The study aims to assess the impact of bioagents on growth and yield parameters of root-knot nematode, Meloidogyne incognita infested mulberry plants. Study Design: The data collected from the experimental field were analyzed statistically by using one-way RCBD. Place and Duration of Study: The experiment was carried out in the root-knot nematode infested mulberry garden in Kalyapura Village, Shidlaghatta Taluk, Chikkaballapura District, Eastern Dry Zone (Zone-5) of Karnataka, India between January to September 2022, covering three harvests. Methodology: The treatments were incorporated near the root zone of mulberry plants within a week after pruning as per the recommendations. The observations were recorded once before the imposition of the treatments (initial) and during the first (60 DAT) and second (120 DAT) shoot harvests in mulberry after imposing the treatments. Results: Among the bioagents Trichoderma viride showed better results for shoot height (120.00 cm), number of leaves per plant (511.75), leaf area (102.10 cm2) and leaf yield per plant (528.38 g) during the second harvest i.e., 120 DAT. The minimum leaf yield per plant was recorded in the untreated check (216.43 g). Conclusion: Incorporating T. viride @ 5 kg/ha mixed with 5 tons FYM near the root zone of mulberry infested with RKN showed promising results in promoting plant growth and yield.

Study on the Function of SlWRKY80 in Tomato Defense against Meloidogyne incognita.

WRKY transcription factors (TFs) can participate in plant biological stress responses and play important roles. SlWRKY80 was found to be differentially expressed in the Mi-1- and Mi-3-resistant tomato lines by RNA-seq and may serve as a key node for disease resistance regulation. This study used RNAi to determine whether SlWRKY80 silencing could influence the sensitivity of 'M82' (mi-1/mi-1)-susceptible lines to M. incognita. Further overexpression of this gene revealed a significant increase in tomato disease resistance, ranging from highly susceptible to susceptible, combined with the identification of growth (plant height, stem diameter, and leaf area) and physiological (soluble sugars and proteins; root activity) indicators, clarifying the role of SlWRKY80 as a positive regulatory factor in tomato defense against M. incognita. Based on this phenomenon, a preliminary exploration of its metabolic signals revealed that SlWRKY80 stimulates different degrees of signaling, such as salicylic acid (SA), jasmonic acid (JA), and ethylene (ETH), and may synergistically regulate reactive oxygen species (ROS) accumulation and scavenging enzyme activity, hindering the formation of feeding sites and ultimately leading to the reduction of root gall growth. To our knowledge, SlWRKY80 has an extremely high utilization value for improving tomato resistance to root-knot nematodes and breeding.

Physiological and Biochemical Responses of Maize to Elevated CO2 Concentrations: Implications for Growth and Metabolism

Rising atmospheric CO2 levels, a significant consequence of anthropogenic activities, profoundly impact global agriculture and food security by altering plant physiological processes. Despite extensive research, a comprehensive understanding of the specific effects of elevated CO2 on maize (Zea mays L.)’s primary and secondary metabolism remains elusive. This study investigated the responses of maize seedlings cultivated in open-top chambers (OTCs) under three CO2 concentrations: ambient (380 ppm), elevated (600 ppm), and high (1800 ppm). Key growth parameters, including plant height, leaf area, and aboveground biomass (leaf and stem), were assessed alongside metabolic profiles encompassing nonstructural and structural carbohydrates, syringyl (S) and guaiacyl lignin, the syringyl-to-guaiacyl (S/G)-lignin ratio, photosynthetic pigments, total soluble protein, and malondialdehyde (MDA) levels. The results demonstrated that exposure to 600 ppm CO2 significantly enhanced plant height, leaf area, and aboveground biomass compared to ambient conditions. Concurrently, there were notable increases in the concentrations of primary metabolites. In contrast, exposure to 1800 ppm CO2 severely inhibited these growth parameters and induced reductions in secondary metabolites, such as chlorophyll and soluble proteins, throughout the growth stages. The findings underscore the intricate responses of maize metabolism to varying CO2 levels, highlighting adaptive strategies in primary and secondary metabolism under changing atmospheric conditions. This research contributes to a nuanced understanding of maize’s physiological adaptations to future climate scenarios characterized by elevated CO2, with implications for sustainable agriculture and food security.

Flooding tolerance, biomass production, and leaf nitrogen assimilatory efficiency in 29 diverse willows (Salix spp.) genotypes during early growth

ABSTRACT Willows are frequently planted as unrooted cuttings in flood-prone areas. The occurrence of a flooding episode during the early stages of the plantation causes diverse morphological and physiological changes in willows. Thus, it is important to identify traits correlating to flooding tolerance to be used to breed genotypes with enhanced tolerance to this stress. In addition, flooding can change nitrogen absorption in plants, altering leaf nitrogen concentration. These changes could influence the photosynthetic activity, and ultimately, the growth of plantations. The aims of this work were: (i) to identify traits that increase flooding tolerance in willows during early growth and (ii) to analyze the effects of flooding on Assimilatory Nitrogen Use Efficiency (ANUE, measured as foliar biomass: foliar nitrogen concentration ratio). Two-month-old plants growing in pots of 29 willow genotypes were flooded with water covering 80% of the stem, for 43 days. At the end of this period, the flooding tolerance index (ratio between the flooded plant biomass to the non-flooded plant biomass) ranged between 39% and 103%. Flooding tolerance had a significant and positive correlation to plant height, diameter, total biomass, growth rate, leaf area, leaf number, and basic wood density. ANUE decreased in flooded plants in most genotypes, despite the increase in leaf nitrogen concentration. This implies that flooded plants were less efficient in the use of nitrogen to produce leaf biomass than the non-flooded treatment. These results are relevant for the selection of flooding tolerance in young willow plants obtained from rootless cuttings.

Impact of microplastic residues from polyurethane films on crop growth: Unraveling insights through transcriptomics and metabolomics analysis

The utilisation of coated controlled-release fertilizers (CRFs) leads to the persistence of residual plastic films in agricultural soils, posing a potential threat to crop health. This study investigates the impacts of four residual films (0.39 %, w/w) derived from CRFs in soil, including petrochemical polyether, bio-based polyether, castor oil polyester, and wheat straw polyester polyurethane on wheat growth. This study found that PecPEUR significantly reduced wheat plant height, stem diameter, leaf area, and aboveground fresh weight by 24.8 %, 20.2 %, and 25.7 %. Through an in-depth exploration of transcriptomics and metabolomics, it has been discovered that all residual films disrupted glycolysis-related metabolic pathways in wheat roots, affecting seedling growth. Among them, PecPEUR significantly reduced the fresh weight of aboveground parts by 20.5 %. In contrast, polyester polyurethane residue had no discernible impact on aboveground wheat growth. This was attributed to the enrichment of wheat root genes in jasmonic acid and γ-aminobutyric acid metabolic pathways, thus mitigating oxidative stress, enhancing stress resistance, and ensuring normal plant growth. This study, for the first time, provides comprehensive insights into the effects of polyurethane film residue on wheat seedling growth, underscoring its potential as a promising alternative to conventional plastics in soil.

Enhancing Spinach (Amaranthus tricolor L.) Growth Using Maggot Fermentation-Derived Liquid Organic Fertilizer and AB Mix in Drip Fertigation Systems

Spinach (Amaranthus tricolor L.) is a highly nutritious leafy vegetable widely cultivated for its rich content of vitamins and minerals. To enhance spinach production sustainably, this study investigates the use of liquid organic fertilizer derived from maggot fermentation combined with AB mix nutrients, applied through a drip fertigation system. The study was conducted using three different concentrations: 2.5 ml/L, 5 ml/L, and 7.5 ml/L, with the goal of identifying optimal conditions for maximizing spinach growth. The research utilized a two-factorial, Completely Randomized Design (CRD) with five replications to evaluate the effects of these nutrient combinations on key growth parameters, including plant height, leaf number, leaf area and weight of plants. Results indicated that a concentration of 7.5 ml/L provided the most favorable growth outcomes, with a 46.5 cm increase in plant height and a biomass accumulation of 61.8 grams, representing significant improvements over control treatments. The macro-nutrient content of the maggot-derived POC met national agricultural standards, except for pH, which improved to 7.10 when combined with AB mix. These findings suggest that integrating maggot POC with AB mix offers a cost-effective and environmentally friendly alternative to conventional fertilizers, promoting sustainable agricultural practices. This study contributes to developing efficient cultivation methods for spinach, addressing increasing market demands, and reducing reliance on chemical fertilizers.

Effect of Zinc on Germination, Growth Yield of (Solanum melongena L.)

Eggplant (Solanum melongena L.) is an economically significant crop, valued for its culinary versatility and nutritional content. Understanding the factors that influence its growth is crucial for optimizing agricultural practices and improving yield. Zinc, an essential micronutrient, plays a vital role in various physiological processes within plants, including enzyme activation, photosynthesis, and hormone regulation. This study investigated the effect of zinc supplementation on the growth parameters of eggplant. The experiment was conducted in Botany Lab of Maharishi University of Information Technology, Lucknow in earthen Pots filled with garden soil. Where eggplant seedlings were subjected to different levels of zinc supplementation. Parameters such as plant height, leaf area, root development, and biomass accumulation were measured at regular intervals over the growth period. Results indicated a significant positive correlation between zinc concentration and various growth parameters of eggplant. Seedlings treated with higher zinc concentrations, enhanced leaf expansion, and more extensive root systems compared to those with lower or no zinc supplementation. Furthermore, zinc-treated eggplants displayed improved resistance to certain environmental stressors, suggesting a potential role of zinc in enhancing plant resilience. These findings underscore the importance of adequate zinc supply in promoting the growth and development of eggplant crops, thereby contributing to higher yields and improved agricultural sustainability. Further research is warranted to elucidate the underlying mechanisms of zinc-mediated growth enhancement in eggplant and optimize zinc application strategies for maximum benefit.

Reduced Chemical Fertilizer Combined with Vermicompost Application Affects the Growth, Yield, and Quality of Watermelon

Continuous application of chemical fertilizers in plant cultivation can lead to the deterioration of the soil environment, resulting in reduced crop yield and quality. Currently, organic fertilizers, such as vermicompost, can partially replace chemical fertilizers and maximize yields while maintaining soil fertility. However, the effects of chemical fertilizers combined with vermicompost on watermelon (Citrullus lanatus) yield and quality are unclear. A field experiment was carried out on the watermelon cultivar Lihua No. 6. Six treatments were applied: no fertilizer (CK, control, 0N–0P–0K), 100% chemical fertilizer [CF, 5.4N–1P–5.4K (256, 47, and 255 kg·ha−1)], 75% chemical fertilizer + 25% organic fertilizer [A1, 5.4N–1P–5.4K (192, 35, and 191 kg·ha−1) + 2250 kg·ha−1 vermicompost], 50% chemical fertilizer + 50% organic fertilizer [A2, 5.4N–1P–5.4K (128, 24, and 127 kg·ha−1) + 4500 kg·ha−1 vermicompost], 25% chemical fertilizer + 75% organic fertilizer [A3, 5.4N–1P–5.4K (64, 12, and 64 kg·ha−1) + 6750 kg·ha−1 vermicompost], and 100% organic fertilizer (A4, 9000 kg·ha−1 vermicompost). Indices related to the growth, yield, and quality of watermelons were determined. Compared with CK, chemical fertilizer alone or in combination with organic fertilizers significantly increased growth parameters (plant height and leaf area) and chlorophyll content. The five fertilizer treatments enhanced the single fruit weight, yield, and biomass. In addition, the yield of reduced chemical fertilizer plus organic fertilizer was comparable to that of watermelons treated with CF. Compared with CF, the fertilizer treatments, especially the 1:1 mixture of chemical and organic fertilizer (A2) group, had elevated fruit-soluble solids and soluble sugar content, and reduced organic acid levels. Therefore, a combination of 50% chemical fertilizer and 50% organic fertilizer can effectively enhance the yield and quality of watermelons. These findings have important implications for guiding the management of watermelon fertilization and development of sustainable agriculture.

Melatonin mitigates cadmium toxicity by promoting root development, delaying root senescence, and regulating cadmium transport in cotton

Cd ions are absorbed and transported from the soil by crop roots, which are the first organ to be exposed to Cd. This results in an increase in cadmium ions in crops, significantly affecting crop growth and yield. Exogenous melatonin (MT) can help reduce cadmium (Cd) stress in cotton, but the specific contribution of roots to this process remains unclear. In order to address this knowledge gap, an in-situ root phenotyping study was conducted to investigate the the phenotype and lifespan of roots under cadmium stress (Cd) and melatonin treatment (Cd + MT). The results showed that MT alleviated the decreases in plant height, leaf area, SPAD value, stem diameter, stomatal conductance and net photosynthetic rate under Cd stress, which further promoted the biomass accumulation in various cotton organs. What is more, the Cd + MT treatment increased root volume, surface area, and length under Cd stress by 25.63 %, 10.58 %, and 21.89 %, respectively, compared with Cd treatment. Interestingly, compared to Cd treatment, Cd + MT treatment also significantly extended the lifespan of roots and root hairs by 6.68 days and 2.18 days, respectively. In addition, Cd + MT treatment reduced the transport of Cd from roots to shoots, particularly to bolls, and decreased the Cd bioconcentration factor in bolls by 61.17 %, compared to Cd treatment. In conclusion, these findings show that applying MT externally helps reduce Cd stress by delaying root senescence, promoting root development and regulating Cd transport. This method can be an effective approach to managing Cd stress in cotton.

Microbial Biostimulants and Seaweed Extract Synergistically Influence Seedling Growth and Morphology of Three Onion Cultivars

Onion (Allium cepa L.), a globally cultivated vegetable crop, possesses a shallow root system, making it vulnerable to abiotic stresses. The increasing frequency of extreme weather events in recent years necessitates sustainable solutions to enhance onion growth. Biostimulants offer a promising and accessible approach to promote onion growth and quality in an environmentally friendly and sustainable manner. This study investigated the effects of nine commercial microbial biostimulants (LALRISE Mycorrhizae, LALRISE Bacillus, Mighty Mycorrhizae, MycoApply, Spectrum DS, Spectrum Myco, Spectrum, Tribus Original, and Tribus Continuum) and one non-microbial commercial biostimulant (Kelpak—seaweed extract) on the seedling growth of three onion cultivars: Carta Blanca (white), Don Victoro (yellow), and Sofire (red). The results indicated that biostimulants did not significantly affect onion seed germination, but germination rates did vary among the onion cultivars. These cultivars also exhibited significant morphological and biomass differences, with principal component analysis revealing a more obvious effect on root growth compared to shoot growth. Kelpak seaweed extract increased the plant height, leaf area, and shoot fresh weight and dry weight of onion seedlings but decreased the root-to-shoot dry-weight ratio. The effects of microbial biostimulants on onion seedling growth depended on both the onion cultivar and Kelpak seaweed extract. In general, LALRISE Mycorrhizae, Mighty Mycorrhizae, Spectrum Myco, Spectrum DS, and Tribus Continuum exhibited positive effects on seedling growth in certain onion cultivars. Furthermore, the benefits of microbial biostimulants were amplified when combined with Kelpak seaweed extract application. These findings suggest a synergistic interaction between microbial and non-microbial biostimulants, leading to enhanced onion seedling growth. Further research is required to evaluate the long-term effects of these biostimulants on onion plant growth after transplanting to fields.

A Dynamic Process-Based Method for Screening Salt-Tolerant and High-Yielding Crop Varieties

Maize, the most important cereal crop worldwide, is moderately sensitive to salt stress. Given the challenges of soil salinization, developing methods to screen and cultivate salt-tolerant maize varieties is vital for enhancing food security. Among the options, process model-based assisted screening is an effective method for faster and more thorough screening of salt-tolerant varieties. In this study, a method for quickly screening salt-tolerant and high-yielding crop varieties is proposed by combining a coupled model of crop growth and water–salt response with fitness function. Then, this method was applied to the saline areas of the Hetao Plain in China to demonstrate its applicability. This study includes three parts. Firstly, field trial data from 10 commonly grown maize varieties in Hetao Plain (i.e., Xianyu 335, Yinyu 238, Jindan 73, Deke 622, DK-815, Heyu 157, Xianyu 1321, Jinrun 919, Tianci 19, and Xianyu 1225) were used to calibrate the model for different maize varieties. Moreover, model accuracy was evaluated using four indexes including the regression coefficient (b), coefficient of determination (R²), root mean square error (RMSE), and Nash–Sutcliffe efficiency coefficient (NSE). Secondly, scenario simulations were conducted using the calibrated model by setting nine initial salinity scenarios to simulate daily dynamic crop growth and soil water–salt changes for the 10 maize varieties. Finally, salt-tolerant and high-yielding maize varieties were screened based on the fitness function method during crop growth periods. The results showed that the simulation model was applicable and functioned effectively for all 10 maize varieties in the region, with the determination coefficient (R2) and Nash–Sutcliffe efficiency coefficient (NSE) of simulated plant height and leaf area index being above 0.90. Furthermore, the R2 of soil water content, soil electrical conductivity, and groundwater depth are 0.51, 0.52, and 0.60, respectively. Afterward, the fitness function values were calculated to bridge the linkage between simulated indicators and scenarios to screen varieties step by step according to the predetermined percentage of screening. Jindan 73, Xianyu 1225, and DK-815 were eventually determined as the most suitable salt-tolerant and high-yielding maize varieties. Therefore, the above results show that the proposed method is suitable for saline crop variety screening with flexibility and applicability.

Integrated management strategies increased silage maize yield and quality with lower nitrogen losses in cold regions.

High-yield and high-quality production of silage maize in cold regions is crucial for ensuring the sustainable development of livestock industry. This study first conducted an experiment to select the optimized silage maize varieties and densities using a split-plot design. The tested maize varieties were Xuntian 3171, Xuntian 16, Xunqing 858, and Fengtian 12, with each variety planted at densities of 67,500, 79,500, and 90,000 plants ha-1. Following the variety and density selection, another experiment on optimizing nitrogen management for silage maize was carried out using a completely randomized design: no nitrogen fertilizer (T1), applying urea-N 320 kg ha-1 (T2), applying urea-N 240 kg ha-1 (T3), applying polymer-coated urea-N 240 kg N ha-1 (T4), and ratios of polymer-coated urea-N to urea-N at 9:1 (T5), 8:2 (T6), 7:3 (T7), and 6:4 (T8). T5-T8 all applied 240 kg N ha-1. The yield and quality of silage maize, nitrogen use efficiency and balance, and economic benefits were evaluated. Results showed that Xunqing 858 had significantly higher plant height (8.7%-22.6% taller than the other three varieties) and leaf area (30.9% larger than Xuntian 3171), resulting in yield 11.5%-51.6% higher than the other three varieties. All varieties achieved maximum yields at a planting density of 79,500 plants ha-1. Integrated management strategy 7 (T7: Xunqing 858, 79,500 plants ha-1, polymer-coated urea-N to urea-N ratio of 7:3) achieved the highest yield of 73.1 t ha-1, a 6.1%-58.1% increase over other treatments. This strategy also produced the highest crude protein (11.1%) and starch (19.1%) contents, and the lowest neutral detergent fiber content (50.6%), with economic benefits improved by 10.3%-97.8% compared to other strategies. Additionally, T7 improved nitrogen use efficiency by 15.4%-94.5%, reduced soil nitrate leaching by 4.4%-36.5%, and decreased nitrogen surplus by 7.0%-46.6%. Comprehensive analysis revealed that the integrated management strategy 7 significantly improved silage maize yield and quality in cold regions while enhancing nitrogen use efficiency and reducing the risk of nitrate leaching, aligning with green agriculture development requirements. These findings will provide vital theoretical insights and practical guidance for high-yield and high-quality silage maize production in cold regions worldwide.

Influence of Urea Foliar Nutrition and Leaf Harvesting Intensity on Growth, Yield Attributes and Yield in Cowpea [Vigna unguiculta (L.) Walp.

A field experiment was undertaken at Farming Systems Research Station (FSRS), Sadanandapuram, Kollam district, Kerala Agricultural University in summer 2022 for studying the effect of growth, yield attributes and yield of cowpea through foliar application of 2% urea and intensity of leaf harvesting. Experimental treatments comprised of 4 levels of foliar nutrition management (2% urea spray at vegetative stage (f1), 2% urea spray at flowering stage (f2), 2% urea spray at vegetative stage and flowering stage (f3), water spray control (f4) and 3 levels of leaf harvest (20% leaf harvest (l1), 40% leaf harvest (l2), and no leaf harvest (l3). Among the foliar nutrition management treatments, f3 showed significantly the taller plants (91.97 cm), more number of branches (15.13), leaves (34.76), leaf area/ plant (884.29 cm2), leaf area index (1.96) dry matter production (42.39 g) and chlorophyll content (3.544 mg/g) and were comparable with f1. The nodule parameters such as nodule number (37.44) and effective number of nodules (32.11) were the highest in treatment f3 and was on par with f1. Further, days to 50 per cent flowering (53.65 days), pod length (17.27 cm), 100 seed weight (12.40 g), pod number (24.58), foliage yield (1484.57 kg ha-1), grain yield (925.85 kg ha-1) and haulm yield (2722.70 kg ha-1) were the highest in treatment f3 and was on par with f1 except for pod weight (21.19 g). Among the leaf harvest intensity, treatment l3 recorded the taller plants (92.45 cm), leaf area per plant (902.71cm2) leaf area index (2.01), less days to 50% flowering (47.60 days) and haulm yield (2754.85 kg ha-1). It was on par with l1 pertaining to plant height. The number of branches (15.03), dry matter production per plant (40.78g), pod weight/plant (19.43 g), pod number/plant (23.59) and grain yield (925.85 kg ha-1) were the highest in treatment l1.

Sub-surface drip fertigation of nitrogen coupled with crop residue incorporation enhanced the growth and yield of maize in an alluvial soils

A two-year field experiment was conducted at ICAR-Indian Agricultural Research Institute, New Delhi, to standardize the N-fertigation schedule and crop residue management in sub-surface drip fertigated (SSDF) maize [Pusa HQPM 1’ improved: double bio-fortified]. The experiment was laid-out in a split-plot design with 3 replications. There were 8 main-plot treatments comprising different N sub-surface drip fertigation levels (0, 50, 75, 100% RDN) with one conventional cultivation of maize, where RDN (150 kg/ha) was applied as per recommendation. Under sub-surface fertigation of N, each dose of N was divided into 3-and 4-splits, for fertigation. Sub-plot treatments included greengram residue (3 t/ha) and no greengram residue incorporation. P and K (60 kg P2 O5 /ha and 40 kg K2 O/ha respectively) fertilizers were supplied equally in all the plots by SSDF. Results revealed that plant height at various stages statistically varied with levels and splits of SSDF-N and crop residue incorporation. The highest plant height and leaf area were recorded with 100% RDN-4S which remained at par with 100% RDN-3S and 75% RDN-4S. Conventional maize cultivation was inferior to ‘RDN100’ and 75%, however on par with 50% RDN. The nitrogen uptake was found significantly superior in 100 and 75%RDN over conventional and control treatments. Similarly, the grain yield of maize was highest under 100% ‘RDN-4’ &3 S, and 75% RDN-4S, which were at par with one another. Overall, it could be concluded that sub-surface fertigation of N not only improved the growth and yield of maize but also helped in 25–50% saving of valuable fertilizer.

Leaf area prediction of sweet potato cultivars: An approach to a non-destructive and accurate method

Many researchers consider the leaf area the most critical parameter for plant growth and physiology studies. Using allometric equations is considered an effective and non-destructive method for estimating the leaf area of plants. The objectives of this study were to construct allometric equations to predict the leaf area of sweet potato cultivars as a function of leaf dimensions and to verify the effectiveness of the allometric equations constructed for each cultivar individually and for the grouped data. Two hundred fifty leaves of the sweet potato cultivars Beauregard, BRS Amélia, BRS Cuia, and Coquinho were collected, and then the length and width of each leaf were measured. Subsequently, the product between leaf length and width and the actual leaf area was calculated. Linear, linear without intercept, power, and exponential regression models were used to construct allometric equations to predict leaf area. The best equations were chosen according to the highest coefficients of determination and correlation, Willmott agreement index, and lowest Akaike information criterion and root mean square error. The equations obtained with the linear models without intercept and power using the length and width of the leaves were the most indicated for predicting the leaf area of sweet potato cultivars.

Prospects for Enhanced Growth and Yield of Blueberry (Vaccinium angustifolium Ait.) Using Organomineral Fertilizers for Reclamation of Disturbed Forest Lands in European Part of Russia

This article presents the results of research on the use of a new granular organomineral fertilizer for growing plants of half-highbush cultivars of the lowbush blueberry (Vaccinium angustifolium Ait.). The purpose of the research is studying the effect of a new granular organomineral fertilizer on the agrobiological characteristics of V. angustifolium plants on a peatland in the conditions of the north of the European part of Russia. The developed composition of organomineral fertilizer (NPK 8:8:8, Fe 0.5%, Zn 0.2%, Cu 0.4%) differs from existing fertilizers in a more balanced ratio of micro- and macroelements and the content of vermicompost containing spore forms of bacteria Bacillus subtilis H-13, B. mucilaginosus, and Azotobacter chroococcum. The use of a new organomineral fertilizer on high-moor peat (pH 2.9) contributed to the highest yield of V. angustifolium fruits (190.2 g/bush), which is 1.2 times more than other mineral fertilizers (NPK, etc.). The best morphophysiological indicators of V. angustifolium plants (leaf area, total and working surface of the roots, root weight) when using the developed organomineral fertilizer were noted in September. An increase of 1.2–1.3 times in the collection of dry matter and sugars in fruits was revealed, compared with other fertilizer options, while the vitamin C content practically did not change. New organomineral fertilizer contributes to the optimal supply of the necessary micro- and macroelements throughout the growing season and increases the productivity of V. angustifolium plants when growing depleted peat deposits in the natural and climatic conditions of the European part of Russia.

Transcriptomics Identifies Differentially Expressed Genes Inducing Tuber Formation in Early- and Late-Maturing Potatoes.

The timing of potato tuberization is affected by potato ripeness, environmental factors, and polygene regulation. The accurate control of the transition to tuberization has both scientific and practical production value, but the key factors regulating this transition remain unclear. This study grafted an early-maturing potato variety (Favorita) scion to the late-maturing Qingshu 9 variety and demonstrated that a heterologous early-maturing scion can induce early potato formation on a late-maturing rootstock. The transcriptome of functional leaves and stolons of grafted plants was comprehensively analyzed and 593 differentially expressed genes (DEGs) were identified, including 38 transcription factors. Based on gene molecular function analysis and previous reports, we propose that PIF5, bHLH93, CBF3, ERF109, TCP19, and YABBY1 are the key DEGs that induce tuber formation in early- and late-maturing potatoes. The YABBY1 gene was subjected to functional verification. The leaf area of StYABBY1-overexpressing plants was smaller than the wild type and no potato tubercles were formed, while an RNA interference plant line showed no change in leaf area and formed tubers, indicating that StYABBY1 has a role in leaf size regulation and tuber formation.

Impacts of Epihomobrassinolide and Thiamethoxam·Flutolanil·Azoxystrobin on the Continuous Cropping Stress of Pinellia ternata

Continuous cropping (CC) stress severely limits the growth and industrial development of Pinellia ternata. Epihomobrassinolide (EBR) is a natural product that widely participates in many the physiological activities of many plants. Thiamethoxam·flutolanil·azoxystrobin (TFA) has been registered as a seed coating agent in crop production. In this work, the effects of seeds soaked with EBR, seeds coated with TFA, and their co-application on the plant growth, electrophysiological information (as physiological activities related to plant electrical signals), leaf photosynthesis, plant resistance, bulb quality, and yield of CC P. ternata were evaluated. The aim of this work is to excogitate a practicable agronomic measure for ameliorating the growth of CC P. ternata. The results show that soaking the seeds with EBR or coating the seeds with TFA could effectively enhance the plant height, leaf area, and stem diameter of CC P. ternata, promote its emergence seedling ratio, and decrease its inverted seedling ratio, and their associated application was found to be more efficient. Additionally, their associated application effectively enhanced the intrinsic capacitance (IC), intracellular water metabolism, nutrient transport, and metabolic activity and decreased the intrinsic resistance (IR), impedance (IZ), capacitive reactance (IXc), and inductive reactance (IXL). Meanwhile, their associated application could reliably enhance the photosynthetic capacity and stress resistance, and effectively improve the bulb quality and yield. This study emphasizes that the associated application of seeds soaked with a 0.004% aqueous EBR solution diluted 1000 times and seeds coated with a 24% TFA flowable concentrate at 1.6 mL kg−1 seed can be used as a novel and practicable technology for alleviating the CC stress of P. ternata and ameliorating its growth, electrophysiological information, resistance, quality, and yield.

PERFORMANCE OF MUNGBEAN WITH ELEVATED NPKS NUTRITIONS UNDER WATER STRESS

Drought is one of the most serious environmental stresses that hinders mungbean (Vigna radiata L.) production seriously. Improvement of soil nutrition is one of the effective measures to enhance drought tolerance of upland crops like mungbean. This study was conducted to evaluate the effect of higher levels of macro nutrients on growth and yield performance of mungbean. Recommended dose, and two, three and four folds of the recommended dose of major fertilizers (N-P-K-S) were applied on two popular mungbean varieties namely, Binamoog-5 and BU mug4 under water stress. The effect of the higher levels of fertilizer on stressed plants was evaluated by examining different morphological parameters of growth such as plant height, parameters of growth analyses, yield attributes and grain yield. Water stress in general had a negative effect on plant growth and development. However, the enhanced levels of nutritions lessened the water stress effect. Increased plant height, leaf area, CGR, RGR, NAR, and grain yield and yield attributes were measured in plants that received elevated nutrients. In general Binamoog-5 showed higher water stress tolerance than BU mug4 in relation to the production of grain yield and yield attrbutes. Under water stress the highest number of pods plant-1 was recorded in T4 where Binamoog-5 produced 15.33 plant-1 and BU mug4 had 13.33 plant-1. The highest 100-seed weight was recorded in Binamoog-5 (4.65 g) and BU mug4 had 4.29 g with the three-fold increased doses of N-P-K-S fertilizer (T4 ). The highest grain yield plant-1 was also recorded in T4 where Binamoog-5 produced 4.95 g plant-1 and BUmug4 produced 3.95 g plant-1. It was concluded that higher levels of NPKS enhanced productivity of mungbean, than the recommended.