Min Kyungwon, Cho Yunseo, Kim Eunjeong, Lee Minho, Lee Sang-Ryong
Department of Biological and Environmental Science, Dongguk University, Seoul 04620, Korea.
Department of Life Science, Dongguk University-Seoul, Goyang 10326, Korea.
Plants (Basel). 2021 Dec 20;10(12):2821. doi: 10.3390/plants10122821.
Exogenous glycine betaine (GB) application has been reported to improve plant tolerance to various abiotic stresses, but its effect on freezing tolerance has not been well studied. We investigated the effect of exogenous GB on freezing tolerance of cabbage ( L.) leaves. Seedlings fed with 30 mM GB via sub-irrigation showed effectively assimilated GB as evident by higher GB concentration. Exogenous GB did not retard leaf-growth (fresh weight, dry weight, and leaf area) rather slightly promoted it. Temperature controlled freeze-thaw tests proved GB-fed plants were more freeze-tolerant as indicated by lower electrolyte leakage (i.e., indication of less membrane damage) and alleviating oxidative stress (less accumulation of O and HO, as well as of malondialdehyde (MDA)) following a relatively moderate or severe freeze-thaw stress, i.e., -2.5 and -3.5 °C. Improved freezing tolerance induced by exogenous GB application may be associated with accumulation of compatible solute (proline) and antioxidant (glutathione). GB-fed leaves also had higher activity of antioxidant enzymes, catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD). These changes, together, may improve freezing tolerance through membrane protection from freeze-desiccation and alleviation of freeze-induced oxidative stress.
据报道，外源施加甘氨酸甜菜碱（GB）可提高植物对各种非生物胁迫的耐受性，但其对耐寒性的影响尚未得到充分研究。我们研究了外源GB对甘蓝叶片耐寒性的影响。通过滴灌给予30 mM GB的幼苗显示出有效地同化了GB，较高的GB浓度即为明证。外源GB并未抑制叶片生长（鲜重、干重和叶面积），反而略有促进作用。温度控制的冻融试验证明，GB处理的植株更耐寒，表现为相对中度或重度冻融胁迫（即-2.5和-3.5°C）后电解质渗漏较低（即膜损伤较小的指标）以及氧化应激减轻（O和H₂O以及丙二醛（MDA）积累较少）。外源施加GB诱导的耐寒性提高可能与相容性溶质（脯氨酸）和抗氧化剂（谷胱甘肽）的积累有关。GB处理的叶片还具有较高的抗氧化酶活性，即过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）和超氧化物歧化酶（SOD）。这些变化共同作用，可能通过保护膜免受冻害脱水并减轻冻融诱导的氧化应激来提高耐寒性。
