Quan Jin, Zheng Weiwei, Wu Meifang, Shen Zhuojun, Tan Jingru, Li Zewei, Zhu Biao, Hong Seung-Beom, Zhao Yanting, Zhu Zhujun, Zang Yunxiang
Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou 311300, China.
Department of Biotechnology, University of Houston Clear Lake, Houston, TX 77058-1098, USA.
Plants (Basel). 2022 Apr 29;11(9):1213. doi: 10.3390/plants11091213.
Heat stress is one of the major abiotic factors that limit the growth, development, and productivity of plants. Both glycine betaine (GB) and β-aminobutyric acid (BABA) have received considerable attention due to their roles in stimulating tolerance to diverse abiotic stresses. In order to understand how GB and BABA biostimulants alleviate heat stress in a cool-weather Chinese cabbage ( L. ssp. ) plant, we investigated the GB- and BABA-primed heat-stressed plants in terms of their morpho-physiological and biochemical traits. Priming with GB (15 mM) and BABA (0.2 mM) was conducted at the third leaf stage by applying foliar sprays daily for 5 days before 5 days of heat stress (45 °C in 16 h light/35 °C in 8 h dark) on Chinese cabbage seedlings. The results indicate that GB and BABA significantly increased chlorophyll content, and the parameters of both gas exchange and chlorophyll fluorescence, of Chinese cabbage under heat stress. Compared with the unprimed heat-stressed control, the dry weights of GB- and BABA-primed plants were significantly increased by 36.36% and 45.45%, respectively. GB and BABA priming also greatly mitigated membrane damage, as indicated by the reduction in malondialdehyde (MDA) and electrolyte leakage through the elevation of proline content, and increased activity levels of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX). Taken together, GB and BABA have great potential to enhance the thermotolerance of Chinese cabbage through higher photosynthesis performance, osmoprotection, and antioxidant enzyme activity.
热胁迫是限制植物生长、发育和生产力的主要非生物因素之一。甘氨酸甜菜碱（GB）和β-氨基丁酸（BABA）因其在刺激植物对多种非生物胁迫的耐受性方面的作用而受到广泛关注。为了了解GB和BABA生物刺激剂如何缓解冷季大白菜（L. ssp.）植株的热胁迫，我们从形态生理和生化特性方面对经GB和BABA预处理的热胁迫植株进行了研究。在大白菜幼苗进行5天热胁迫（45℃光照16小时/35℃黑暗8小时）前5天，于第三片叶期通过每日叶面喷施的方式进行GB（15 mM）和BABA（0.2 mM）预处理，持续5天。结果表明，GB和BABA显著提高了热胁迫下大白菜的叶绿素含量、气体交换参数和叶绿素荧光参数。与未预处理的热胁迫对照相比，经GB和BABA预处理的植株干重分别显著增加了36.36%和45.45%。GB和BABA预处理还极大地减轻了膜损伤，表现为丙二醛（MDA）含量降低和电解质渗漏减少，同时脯氨酸含量升高，超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）的活性水平增加。综上所述，GB和BABA通过提高光合作用性能、渗透保护作用和抗氧化酶活性，在增强大白菜耐热性方面具有巨大潜力。
