Journal of Plant Stress Physiology

Growth and biomass yield responses of Sphenostylis stenocarpa (Hochst. Ex A. Rich.) Harms accessions to waterlogging stress

Okon Godwin Okon — 2024-01-29

Effects of waterlogging on the growth of six accessions of Sphenostylis stenocarpa were investigated. There accessions were TSs-5, TSs-7, TSs-8, TSs-9 TSs-10 and TSs-11. After growing S. stenocarpa for 4 weeks, results indicated that waterlogging significantly (p=0.05) reduced its growth parameters of S. stenocarpa. For shoot length; TSs-9 recorded the highest value (48.27±2.92 cm) above its control while TSs-11 (17.96±1.13 cm) had the lowest value. For petiole length, TSs-9 (3.62±0.33 cm) recorded the highest value while TSs-8 (0.93±0.93 cm) recorded the lowest value. Internode length had TSs-7 (6.10±0.78 cm) had the highest value while TSs-8 (2.87±2.87 cm) had the lowest value. The total photosynthetic pigment measurement showed that TSs-5 (45.0±0.65 mg/kg) with the highest value and TSs-8 (33.37±14.00 mg/kg) had the lowest value. For leaf area, TSs-7 (25.73±4.21 cm²) had the highest value while TSs-11 (16.13±2.82 cm²) recorded the lowest value. Total Fresh Weight (TFW), TSs-7 recorded the highest value (4.96 g) while TSs-8 recorded the lowest value (1.75 g). Root Fresh Weight (RFW), Tss-5 was observed to have the highest value (1.44 g) while Tss-11 recorded the lowest value (0.56 g). However, at 2 weeks after planting the effect of waterlogging stress on the growth parameter was not significant. The reduction in the growth of S. stenocarpa as a result of waterlogging stress might be due to the detrimental effect of flooding on O₂availability for plant cells and other plant metabolic activities of the plant. In areas with waterlogged soil conditions, S. stenocarpa should not be cultivated as it has poor and relatively low tolerance towards withstanding the impact of waterlogging; however, accession TSs-9 showed promising waterlogging tolerance ability.

An overview on Azelaic Acid: Biosynthesis, signalling and the action under stress conditions in plants

Burcu Seckin Dinler — 2024-02-06

Plants are exposed to various biotic and abiotic stress factors throughout their lives. For this reason, they have developed some defense mechanisms. They can induce systemic acquired resistance (SAR), which provides long-lasting protection against diverse pathogen attacks. In recent years, several chemical inducers (salicylic acid, glyceraldehyde-3-phosphate, azelaic acid, pipecolic acid, and dehydroabietic acid) have been determined to play roles in this mechanism. The transfer of these signal molecules from infected tissue to non-infected tissues through phloem provides potent defence communication. Azelaic acid is a well-known molecule that triggers salicylic acid accumulation under biotic stress as a priming factor to induce SAR, although little is known about its role under abiotic stress. Here, this review aims to call attention to the effects of AzA under abiotic stress conditions as well as biosynthesis, transport and signalling.

Elevated osmolytes accumulation helps in combating NaCl stress causing negative impacts on growth and metabolism of Vigna radiata (L.)

Reyaz Ahmad Mir — 2024-04-27

Salinity stress is one of the main abiotic stresses that have a negative impact on the growth performance of green gram. The current study was carried out as a result to find out growth, and morpho-biochemical changes in Vigna radiata CO7 variety cultivated under NaCl stress treatments. The V. radiata CO7 variety was selected and the experiment was carried out in pot culture under varying NaCl concentrations viz., 0, 50, 75, 100, and 125 mM respectively to assess maximum tolerance range of the CO7 variety. The salt stress was given on 15th days after sowing and sampling was done after 10 days of treatment on the 25^th, 35^th, and 45^th day respectively. Salt stress results in a steep decline in shoot length, biomass, chlorophyll contents a and b, and soluble protein contents with increased NaCl treatments on all sampling days. However, carotenoid contents, and compatible solutes including proline, Glycine-betaine, Amino acids and total soluble sugars contents were found to be upregulated under varying NaCl concentrations in V. radiata CO7 variety on all sampling days. Thus, increased carotenoid contents, and osmolytes, provide stress tolerance to V. radiata CO7 variety by maintaining the turgor pressure of cells and preventing further water loss under varying NaCl concentrations. Hence, this variety shows maximum surveillance at 75 mM and beyond this plant performance is restricted and further study is needed to access CO7 variety for a breeding program to enhance salt stress tolerance.

Efficacy of chlorophyll a fluorescence kinetics and JIP test for early detection of leaf-gall disease in Cordia dichotoma

Upma Bhatt — 2024-05-23

Gall-induced oxidative stress impairs photosynthesis and ultimately negatively affects a plant’s productivity and yield. Cordia dichotoma is an economically important plant that suffers from galls produced by the insect Aceria gallae. So we investigated how plants deal with such biotic stress by studying chlorophyll fluorescence OJIP transient analysis. The results indicate the intensive variations in minimum-maximum fluorescence, electron transport, light-harvesting efficiency and density of active reaction centers. When reaction centers become inactive in severely infected leaves a significant rise in ABS/RC and TR/RC indicates the expanded antenna size of Photosystem-II which shows the plant's efforts to enhance photon absorption. But the electron transport was blocked due to OECs deactivation, remarkably altered ET/RC and phenomenological fluxes (ABS/CS, TR/CS and ET/CS). The J-curve distortion confirms blockage of electron transport towards PS-I since PQ is fully reduced and unable to grape electrons from Q_B. Leaf galls carry out noteworthy alterations in Kp, Kn, and primary and secondary photochemistry. But more severe infection causes complete obstruction for electron transport which finally diminishes performance indices (PIabs and PIcs) quantum yield of photosynthesis (φPo), and electron transport (φEo) which increases dissipation and eventually causes the death of the most severely infested leaf. Present studies reveal that measurement of F_V/F₀, PIabs, and PIcs may be used as a physiological marker for the early diagnosis of gall stress in C. dichotoma. Our results also suggest that repetitive detection of photosynthetic performance through chlorophyll a fluorescence analysis and a JIP-test can be used as potent tools to prevent plants from appearing the visible symptoms of any pathogenic infection.

Plant defense mechanism in combined stresses - cellular and molecular perspective

Suphia Rafique — 2024-07-10

The various abiotic stresses negatively influence the growth and development of plants. However, recent predictions of global climate change models have amplified the chances that plants will encounter new and more combinations of abiotic and biotic stresses. The plants adopt different strategies in combined stresses as compared to a single stress. This stress combination can be antagonist or synergistic depending on the interaction of stresses. Plants are sessile, to resists these stresses they activate defense mechanism which are complex cellular and molecular responses under combined stress conditions. At the cellular level, various kinds of biomolecules are produced that have positive and negative effects against stresses. The basic cellular process generates more reactive oxygen species (ROS) in stress conditions and causes extensive damage and inhibition of photosynthesis. Various plant hormones are involved in cellular activations to adapt the plants under stressful conditions. Further, to overcome the adverse effects of stress, the plant activates several molecular cascade mechanisms involving kinases, transcription factors, micro-RNAs, heat shock proteins, epigenetic changes. Besides, plants developed a robust signal perception and transduction mechanism to cope effectively with unfavorable conditions. Phytohormone plays a crucial role in signaling that is activated in response to combined stress conditions and in individual stress which are activated in response to abiotic and biotic stress combinations. Besides, ROS is also involved in signaling. They control a broad range of biological processes and have a conserved signaling network. Therefore, the crosstalk between different signaling pathways activates defense mechanisms and helps in the survival of plants from the various combined abiotic and biotic stress conditions.