Key Laboratory of Genetics and Germplasm Innovation of Tropical Special Forest Trees and Ornamental Plants, Ministry of Education, College of Forestry, Hainan University, Haikou, 570228, P.R. China.
Sci Rep. 2020 Apr 24;10(1):6942. doi: 10.1038/s41598-020-63447-0.
Changing climatic scenarios affect plant growth and consequences are more malicious in drought conditions. This study was performed for better understanding of tolerance mechanisms under prevailing drought stress and succeeding recovery in Axonopus compressus by exogenously applied abscisic acid (ABA) and glycine betaine (GB). Three A. compressus accessions (A-38, A-58 and A-59) were subjected to well-watered (100% field capacity) and drought (40% field capacity) conditions. Two weeks later, plants were recovered from drought by re-watering. Water (control), GB, ABA and their combination were foliar applied on plants under drought twice a week until recovery. Drought stress decreased photosynthetic pigments and increased reactive oxygen species, lipid peroxidation, osmolytes and antioxidants in all accessions of A. compressus. Nonetheless, exogenous ABA and GB alone or in combination improved drought tolerance in all accessions which was maintained even after recovery. Maximum decrease in hydrogen peroxide and malondialdehyde, and increase in soluble sugars, proteins, proline, phenolics and chlorophyll contents, and superoxide dismutase, catalase, peroxidase and ascorbate peroxidase activity was recorded when GB was applied alone under drought. Order of improvement in drought tolerance among accessions was A-58 > A-59 > A-38. In conclusion, improved drought tolerance mechanisms by ABA and GB in A. compressus were retained even after recovery.
气候变化情景影响植物生长，在干旱条件下后果更为严重。本研究旨在通过外源施加脱落酸（ABA）和甘氨酸甜菜碱（GB），更好地了解 Axonopus compressus 在当前干旱胁迫下的耐受机制及其随后的恢复。将三种 A. compressus 品种（A-38、A-58 和 A-59）置于充分浇水（田间持水量的 100%）和干旱（田间持水量的 40%）条件下。两周后，通过重新浇水使植物从干旱中恢复。在干旱条件下，每周两次向叶片喷施外源 GB、ABA 及其组合，直至恢复。干旱胁迫降低了光合色素，增加了活性氧、脂质过氧化、渗透调节剂和抗氧化剂在 A. compressus 的所有品种中。然而，外源 ABA 和 GB 单独或联合使用提高了所有品种的耐旱性，即使在恢复后也能维持。在干旱条件下单独施用 GB 时，过氧化氢和丙二醛的最大减少，可溶性糖、蛋白质、脯氨酸、酚类和叶绿素含量以及超氧化物歧化酶、过氧化氢酶、过氧化物酶和抗坏血酸过氧化物酶活性的增加最为显著。各品种耐旱性的改善顺序为 A-58 > A-59 > A-38。总之，ABA 和 GB 在 A. compressus 中提高耐旱性的机制在恢复后仍能保留。
