Fertigation with Zn-Lysine Confers Better Photosynthetic Efficiency and Yield in Water Stressed Maize: Water Relations, Antioxidative Defense Mechanism and Nutrient Acquisition

Optimizing water relations, gas exchange parameters, biochemical attributes and yield of water-stressed maize plants through seed priming with iron oxide nanoparticles

Drought poses significant risks to maize cultivation by impairing plant growth, water uptake and yield; nano priming offers a promising avenue to mitigate these effects by enhancing plant water relations, stress tolerance and overall productivity. In the current experiment, we tested a hypothesis that seed priming with iron oxide nanoparticles (n-Fe2O3) can improve maize performance under water stress by improving its growth, water relations, yield and biochemical attributes. The experiment was conducted on a one main plot bisected into two subplots corresponding to the water and drought environments. Within each subplot, maize plants were raised from n-Fe2O3 primed seeds corresponding to 0 mg. L- 1 (as control treatment), 25, 50, 75, and 100 mg. L- 1 (as trial treatments). Seed priming with n-Fe2O3 at a concentration of 75 mg. L- 1 improved the leaf relative water content, water potential, photosynthetic water use efficiency, and leaf intrinsic water use efficiency of maize plants by 13%, 44%, 64% and 17%, respectively compared to control under drought stress. The same treatments improved plant biochemical attributes such as total chlorophyll content, total flavonoids and ascorbic acid by 37%, 22%, and 36%, respectively. Seed priming with n-Fe2O3 accelerated the functioning of antioxidant enzymes such as SOD and POD and depressed the levels of leaf malondialdehyde and hydrogen peroxide significantly. Seed priming with n-Fe2O3 at a concentration of 75 mg. L- 1 improved cob length, number of kernel rows per cob, and 100 kernel weight by 59%, 27% and 33%, respectively, under drought stress. Seed priming with n-Fe2O3 can be used to increase maize production under limited water scenarios.

Alpha lipoic acid mitigates adverse impacts of drought stress on growth and yield of mungbean: photosynthetic pigments, and antioxidative defense mechanism

Context

Exogenous use of potential organic compounds through different modes is a promising strategy for the induction of water stress tolerance in crop plants for better yield.

Aims

The present study aimed to explore the potential role of alpha-lipoic acid (ALA) in inducing water stress tolerance in mungbean lines when applied exogenously through various modes.

Methods

The experiment was conducted in a field with a split-plot arrangement, having three replicates for each treatment. Two irrigation regimes, including normal and reduced irrigation, were applied. The plants allocated to reduced irrigation were watered only at the reproductive stage. Three levels of ALA (0, 0.1, 0.15 mM) were applied through different modes (seed priming, foliar or priming+foliar).

Key results

ALA treatment through different modes manifested higher growth under reduced irrigation (water stress) and normal irrigation. Compared to the other two modes, the application of ALA as seed priming was found more effective in ameliorating the adverse impacts of water stress on growth and yield associated with their better content of leaf photosynthetic pigments, maintenance of plant water relations, levels of non-enzymatic antioxidants, improved activities of enzymatic antioxidants, and decreased lipid peroxidation and H2O2 levels. The maximum increase in shoot fresh weight (29% and 28%), shoot dry weight (27% and 24%), 100-grain weight (24% and 23%) and total grain yield (20% and 21%) in water-stressed mungbean plants of line 16003 and 16004, respectively, was recorded due to ALA seed priming than other modes of applications.

Conclusions

Conclusively, 0.1 and 0.15 mM levels of ALA as seed priming were found to reduce the adverse impact of water stress on mungbean yield that was associated with improved physio-biochemical mechanisms.

Implications

The findings of the study will be helpful for the agriculturalists working in arid and semi-arid regions to obtain a better yield of mungbean that will be helpful to fulfill the food demand in those areas to some extent.

Effects of pulsed Nd:YAG laser kernel irradiation on maize (Zea mays L.): Insights into germination, gas exchange, photosynthetic pigments, and morphological modifications

Energy has always been the most concerned topic worldwide due to its large consumption. Among various types of energies, light has amazing characteristics and have interesting effects on living organisms. Interest is increasing in the use of laser kernel treatment as an environment friendly physical technique for better results in agronomic crops, but the work is still in progress. The present study was conducted with the aim to examine the application of range of Neodymium-doped Yttrium Aluminum Garnet (Nd:YAG) pulsed laser exposures (200, 400, 600, 800, 1000, 1200, 1400 J/cm2) as pre-sowing kernel treatment on seedling survival rate, leaf photosynthetic activity in relation with photosynthetic pigments and visual morphological effects at seedling to maturity stage. Results showed that the low laser exposure (200, 400 and 600 J/cm2) improved the photosynthetic activity in parallel with improvement in chlorophyll a, chlorophyll b, total chlorophyll, carotenoids as well as morphological traits. Kernel treatments with higher laser fluences (800, 1000, 1200 and 1400 J/cm2) showed irregular responses in studied attributes examined at the individual plant level. At 800 and 1000 J/cm2 improvements were found in some plants but at higher doses clear negative impacts were recorded on studied attributes. In conclusion, the lower doses of Nd:YAG pulsed laser fluences are found beneficial for induction of improvement in maize plants for better growth but higher doses were found toxic ones. In future further studies are needed to check the impacts of low laser doses on yield related attributes under field conditions and the high doses might also be used to create variants with beneficial characteristics if possible.

Alleviation of cadmium toxicity in pea (Pisum sativum L.) through Zn-Lys supplementation and its effects on growth and antioxidant defense

Cadmium significantly impacts plant growth and productivity by disrupting physiological, biochemical, and oxidative defenses, leading to severe damage. The application of Zn-Lys improves plant growth while reducing the stress caused by heavy metals on plants. By focusing on cadmium stress and potential of Zn-Lys on pea, we conducted a pot-based study, organized under completely randomized block design CRD-factorial at the Botanical Garden of Government College University, Faisalabad. Both pea cultivars were grown in several concentrations of cadmium @ 0, 50 and 100 μM, and Zn-Lys were exogenously applied @ 0 mg/L and 10 mg/L with three replicates for each treatment. Cd-toxicity potentially reduces plant growth, chlorophyll contents, osmoprotectants, and anthocyanin content; however, an increase in MDA, H2O2 initiation, enzymatic antioxidant activities as well as phenolic, flavonoid, proline was observed. Remarkably, exogenously applied Zn-Lys significantly enhanced the plant growth, biomass, photosynthetic attributes, osmoprotectants, and anthocyanin contents, while further increase in enzymatic antioxidant activities, total phenolic, flavonoid, and proline contents were noticed. However, application of Zn-Lys instigated a remarkable decrease in levels of MDA and H2O2. It can be suggested with recommendation to check the potential of Zn-Lys on plants under cadmium-based toxic soil.

Tryptophan Seed Treatment Improves Morphological, Biochemical, and Photosynthetic Attributes of the Sunflower under Cadmium Stress

Tryptophan, as a signal molecule, mediates many biotic and environmental stress-induced physiological responses in plants. Therefore, an experiment was conducted to evaluate the effect of tryptophan seed treatment in response to cadmium stress (0, 0.15, and 0.25 mM) in sunflower plants. Different growth and biochemical parameters were determined to compare the efficiency of the treatment agent. The results showed that cadmium stress reduced the growth attributes, including root and shoot length, dry and fresh weight, rate of seed germination, and the number of leaves. Cadmium stress also significantly reduced the contents of chlorophyll a, b, and total chlorophyll, carotenoid contents, phenolics, flavonoids, anthocyanin, and ascorbic acid. Whereas cadmium stress (0.15 and 0.25 mM) enhanced the concentrations of malondialdehyde (45.24% and 53.06%), hydrogen peroxide (-11.07% and 5.86%), and soluble sugars (28.05% and 50.34%) compared to the control. Tryptophan treatment decreased the effect of Cd stress by minimizing lipid peroxidation. Seed treatment with tryptophan under cadmium stress improved the root (19.40%) and shoot length (38.14%), root (41.90%) and shoot fresh weight (13.58%), seed germination ability (13.79%), average leaf area (24.07%), chlorophyll b (51.35%), total chlorophyll (20.04%), carotenoids (43.37%), total phenolic (1.47%), flavonoids (19.02%), anthocyanin (26.57%), ascorbic acid (4%), and total soluble proteins (12.32%) compared with control conditions. Overall, the tryptophan seed treatment showed positive effects on sunflower plants' growth and stress tolerance, highlighting its potential as a sustainable approach to improve crop performance.

Synergistic application of calcium oxide nanoparticles and farmyard manure induces cadmium tolerance in mung bean (Vigna radiata L.) by influencing physiological and biochemical parameters

Mung bean (Vigna radiata L.) grown under heavy metals such as cadmium stress shows poor growth patterns and yield attributes which can be extenuated by the application of calcium and organic manure to the contaminated soil. The present study was designed to decipher the calcium oxide nanoparticles and farmyard manure-induced Cd stress tolerance through improvement in physiological and biochemical attributes of mung bean plants. A pot experiment was conducted by defining appropriate positive and negative controls under differential soil treatments with farmyard manure (1% and 2%) and calcium oxide nanoparticles (0, 5, 10, and 20 mg/L). Root treatment of 20 mg/L calcium oxide nanoparticles (CaONPs) and 2% farmyard manure (FM) reduced the cadmium acquisition from the soil and improved growth in terms of plant height by 27.4% compared to positive control under Cd stress. The same treatment improved shoot vitamin C (ascorbic acid) contents by 35% and functioning of antioxidant enzymes catalase and phenyl ammonia lyase by 16% and 51%, respectively and the levels of malondialdehyde and hydrogen peroxide decreased by 57% and 42%, respectively with the application of 20 mg/L CaONPs and 2% of FM. The gas exchange parameters such as stomata conductance and leaf net transpiration rate were improved due to FM mediated better availability of water. The FM improved soil nutrient contents and friendly biota culminating in good yields. Overall, 2% FM and 20 mg/L CaONPs proved as the best treatment to reduce cadmium toxicity. The growth, yield, and crop performance in terms of physiological and biochemical attributes can be improved by the application of CaONPs and FM under the heavy metal stress.