Ahmad Saif, Fariduddin Qazi
Plant Physiology and Biochemistry Section, Department of Botany, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, 202002, India.
Environ Sci Pollut Res Int. 2025 Mar;32(15):9676-9696. doi: 10.1007/s11356-025-36263-0. Epub 2025 Mar 26.
GABA serves as the major metabolite and signaling molecule for plant growth and development under fluctuating environmental conditions. In the present study, the effect of different concentrations of GABA (0, 0.25, 0.5, or 0.75 mM) as foliar spray or seed soaking treatment on K-21 and S-22 varieties of tomato (Solanum lycopersicum L.) under normal and NaCl stress (150 mM) was studied. At 40 days after transplantation (DAT), NaCl stress impaired the photosynthetic apparatus, elevated reactive oxygen species (ROS) and malondialdehyde (MDA) levels, and reduced photosynthetic traits and related enzymes, and consequently compromised plant growth and development. However, among the different concentrations of GABA tested 0.5 mM of GABA applied through foliar mode proved best in improving growth, photosynthetic traits (like P of K-21 and S-22 varieties by 39.17% and 30.35%, gs by 40.11% and 32.37%; Ci by 39.48% and 33.67%; E by 37.98% and 30.08% respectively, compared to control group) and enzyme activities (Rubisco, succinate dehydrogenase, and fumarase activity) maintained organization of chloroplast in the leaves and also improved lycopene and β-carotene contents in fruits of tomato plants. Moreover, treatment of GABA (0.5 mM) reduced levels of ROS (such as decreased the contents of O by 38.10% and 34.05%; and HO by 35.95% and 30.36% respectively, in K-21 and S-22 varieties, as compared to their control) and cell death compared to non-treated tomato plants. Foliar application of GABA (0.5 mM) also was more effective than seed soaking to overcome the adverse effects of salt stress specifically in K-21 than S-22 variety. This study addresses this gap and uniquely investigates role of GABA in regulating photosynthetic (Rubisco), GABA shunt, and respiratory (fumarase, succinate dehydrogenase) enzyme activities under salt stress, offering new insights into its multifaceted stress-mitigating potential.
在环境条件波动的情况下，γ-氨基丁酸（GABA）是植物生长发育的主要代谢产物和信号分子。在本研究中，研究了不同浓度（0、0.25、0.5或0.75 mM）的GABA进行叶面喷施或种子浸泡处理，对正常和NaCl胁迫（150 mM）下番茄（Solanum lycopersicum L.）K-21和S-22品种的影响。移栽后40天（DAT），NaCl胁迫损害了光合机构，提高了活性氧（ROS）和丙二醛（MDA）水平，降低了光合特性和相关酶活性，从而影响了植物的生长发育。然而，在所测试的不同浓度的GABA中，通过叶面喷施0.5 mM的GABA在改善生长、光合特性（如K-21和S-22品种的净光合速率分别比对照组提高39.17%和30.35%，气孔导度分别提高40.11%和32.37%；胞间二氧化碳浓度分别提高39.48%和33.67%；蒸腾速率分别提高37.98%和30.08%）和酶活性（核酮糖-1,5-二磷酸羧化酶、琥珀酸脱氢酶和富马酸酶活性）方面效果最佳，维持了叶片叶绿体的结构，还提高了番茄植株果实中番茄红素和β-胡萝卜素的含量。此外，与未处理的番茄植株相比，GABA（0.5 mM）处理降低了ROS水平（如K-21和S-22品种中O含量分别降低38.10%和34.05%；H₂O₂含量分别降低35.95%和30.36%）和细胞死亡。叶面喷施GABA（0.5 mM）在克服盐胁迫的不利影响方面也比种子浸泡更有效，特别是在K-21品种中比S-22品种更有效。本研究填补了这一空白，独特地研究了GABA在盐胁迫下调节光合（核酮糖-1,5-二磷酸羧化酶）、GABA分流和呼吸（富马酸酶、琥珀酸脱氢酶）酶活性中的作用，为其多方面的缓解胁迫潜力提供了新的见解。
