Search

BACKGROUND: β‐N‐oxalyl‐l‐α,β‐diaminopropionic acid (β‐ODAP) is a physiological indicator in response to drying soil. However, how abscisic acid (ABA) modulates β‐ODAP accumulation and its related agronomic characteristics in drought stressed grass pea (Lathyrus sativus L.) continue to be unclear. The present study aimed to evaluate the effects of ABA addition on drought tolerance, agronomic characteristics and β‐ODAP content in grass pea under drought stress. RESULTS: Exogenous ABA significantly promoted ABA levels by 19.3% and 18.3% under moderate and severe drought stress, respectively, compared to CK (without ABA, used as control check treatment). ABA addition activated earlier trigger of non‐hydraulic root‐sourced signal at 69.1% field capacity (FC) (65.5% FC in CK) and accordingly prolonged its operation period to 45.6% FC (49.0% FC in CK). This phenomenon was mechanically associated with the physiological mediation of ABA, where its addition significantly promoted the activities of leaf superoxide dismutase, catalase and peroxidase enzymes and the biosynthesis of leaf proline, simultaneously lowering the accumulation of malondialdehyde and hydrogen peroxide under moderate and severe stresses. Interestingly, ABA application significantly increased seed β‐ODAP content by 21.7% and 21.3% under moderate and severe drought stress, but did not change leaf β‐ODAP content. Furthermore, ABA application produced similar shoot biomass and grain yield as control groups. CONCLUSION: Exogenous ABA improved the drought adaptability of grass pea and promoted the synthesis of β‐ODAP in seeds but not in leaves. Our findings provide novel insights into the agronomic role of ABA in relation to β‐ODAP enrichment in grass pea subjected to drought stress. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Thiamin, an important member of the vitamin B family, is believed to play a significant role in mitigating environmental stresses including drought stress. In turnip, drought stress causes a reduced growth, biomass yield, pigment content, total phenolics and ascorbic acid (AsA), particularly at 50% field capacity (F.C.) in the two cultivars (cv) studied. However, a significant enhancement was observed in the contents of leaf proline, glycinebetaine (GB), malondialdehyde (MDA), hydrogen peroxide (H2O2) and the activities of catalase (CAT) and superoxide dismutase (SOD) as well as root proline, GB, total phenolics, AsA, H2O2, MDA and the activities of peroxidase (POD) and SOD. However, foliar-applied thiamin significantly improved (particularly 100 mM) all the growth attributes, photosynthetic pigments, leaf and root osmoprotectants (GB and proline), AsA, total phenolics and the activities of enzymatic antioxidants such as SOD and POD as well as root CAT in both turnip cultivars under drought stress conditions. Foliar application of thiamin was effective in decreasing the leaf and root H2O2 and MDA content in both cultivars particularly at 50% F.C. Thiamin-induced growth of both turnip cultivars, particularly of cv. Purple Top, was found to be associated with increased photosynthetic pigments, proline and GB contents and antioxidant capacity, but reduced levels of reactive oxygen species (ROS) under water deficit conditions. So, it is suggested that exogenous application of thiamin can be effective in improving drought tolerance of plants. [ABSTRACT FROM AUTHOR]

This study was carried out to assess the influence of trehalose, a non-reducing disaccharide involved in improving plant stress tolerance, on two cultivars (Hysun 33 and FH 598) of sunflower (Helianthus annuus L.) grown under control and drought stress conditions. At pre-flowering stage, varying concentrations (10, 20 and 30 mM) of trehalose were applied to the foliage. Drought stress significantly suppressed the plant growth, total soluble proteins, chlorophyll, achene yield per plant, oil percentage, organic contents, as well as oil palmitic and linoleic acids in both sunflower cultivars. External application of trehalose significantly reduced RMP (relative membrane permeability), and the accumulation of H2O2 (hydrogen peroxide), while a considerable improvement was recorded in shoot fresh and shoot and root dry weights, total soluble proteins, glycinebetaine, AsA (ascorbic acid), total phenolics, achene yield per plant, oil contents, inorganic and organic contents, and the activities of catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD) enzymes under water-limited regimes. The cultivar Hysun 33 was superior to the other cultivar in plant growth, RMP, glycinebetaine, proline, achene yield per plant, oil contents, and palmitic and linoleic acids. Overall, foliar-applied trehalose improved plant growth, oxidative defense system, yield and oil composition of sunflower under drought stress conditions. [ABSTRACT FROM AUTHOR]

Better crop yield and precise future farming system is a dire need to meet the chronic food insecurity predominant these days. Positive interaction between Nitrogen, Phosphorus fertilizers and better plant growth are well known; in contrast no information is available about their role when applied in combination with (Proline+ H2O2). The present experiment was conducted to assess the modulation in grain yield related attributes and biochemical parameters through foliar application of bio-chemicals (Proline+ H2O2) and fertilizer (N+P) application as rooting medium for two wheat cultivars Millat -06 and Shafaq-11. The results exhibited that most of the yield related and biochemical attributes responded positively and significantly to NP fertilizer application. NP treatments, 80-60 kg/ha and 120-90 kg/ha both levels almost equally contributed to increase all studied attributes. It was deducted that application of Proline and H2O2 as foliar spray also caused improvement in term of yield related attributes, but effect was more prominent in biochemical attributes. Application of H2O2 increased the activities of Ascorbate per oxidase (APX), Ascorbic acid (AsA), while foliar spray of pro line enhanced accumulation of Phenolic contents. Catalase activity (CAT) significantly increased with bio-chemicals (Proline+ H2O2) but showed differential response in both cultivars. Foliar spray of biochemical especially H2O2 decreased lipid peroxidation. Concerning the accumulation of endogenous H2O2 contents reached its maximum value with foliar spray of exogenous H2O2. However, foliar spray of bio-chemicals mitigated the deleterious effects of any stressful condition and activate plant antioxidative defense system that ultimately resulted in better growth and productivity. Wheat Millat-11 was better in Plant height, fertile and non-fertile spikelets and Ascorbic acid (Vitamin c) attributes, while Shaafaq-06 was better in 100-grains weight. Overall, our results suggest 5445 that improvement in yield and biochemical parameters was associated with NP fertilizers as well as foliar spray of Pro line and H2O2. [ABSTRACT FROM AUTHOR]

A hydroponic experiment was conducted to observe the effects of various cadmium (Cd) levels (0, 50, 100 µM) on morphology and biochemical responses of nine different rice varieties. Initially, seeds were sown in sand in plastic pots. After 16 days of sowing, uniform seedlings were transferred to hydroponic set-up containing Hoagland solution and continuous aeration was provided with aeration pump. After six days, plants were applied the Cd stress for four weeks, then plants were harvested. Plants growth, biomass, photosynthesis, oxidative stress markers contents, antioxidant enzymes activities and Cd uptake in both root and shoot were measured. Results revealed that Cd negatively affected the plant growth as well as photosynthesis; while, oxidative stress and Cd uptake was increased with increasing Cd stress in all nine rice varieties. From this study, it was found that among all nine rice varieties, the Chenab variety was found most tolerant; while, the Kisan Basmati was found most sensitive variety against Cd stress. However, future studies are needed in order to investigate the detailed mechanism of Cd in different varieties of rice. [ABSTRACT FROM AUTHOR]

The present study was conducted to examine the effect of exogenously applied ascorbic acid (AsA) on osmoprotectants and the oxidative defense system in four cultivars (16171, 16183, 16207 and 16246) of safflower under well-watered and water deficit conditions. Water stress (60% field capacity) significantly decreased the shoot and root fresh and dry weights, shoot and root lengths and chlorophyll contents in all four safflower cultivars, while it increased the leaf free proline, total phenolics, total soluble proteins, hydrogen peroxide content and activities of catalase, superoxide dismutase and peroxidase enzymes. Foliar-applied (100 mg L−1 and 150 mg L−¹) ascorbic acid caused a marked improvement in shoot and root fresh and dry weights, plant height, chlorophyll and AsA contents as well as the activity of peroxidase (POD) enzyme particularly under water deficit conditions. It also increased the accumulation of leaf proline, total phenolics, total soluble proteins and glycine betaine (GB) content in all four cultivars. Exogenously applied AsA lowered the contents of MDA and H2O2, and the activities of CAT and SOD enzymes. Overall, exogenously applied AsA had a positive effect on the growth of safflower plants under water deficit conditions which could be related to AsA-induced enhanced osmoprotection and regulation of antioxidant defense system. [ABSTRACT FROM AUTHOR]