PDF(Pubmed)
Abstract：
Illicium difengpi (Schisandraceae), which is an endemic, medicinal, and endangered species found in small and isolated populations that inhabit karst mountain areas, has evolved strategies to adapt to arid environments and is thus an excellent material for exploring the mechanisms of tolerance to severe drought. In experiment I, I. difengpi plants were subjected to three soil watering treatments (CK, well-watered treatment at 50% of the dry soil weight for 18 days; DS, drought stress treatment at 10% of the dry soil weight for 18 days; DS-R, drought-rehydration treatment at 10% of the dry soil weight for 15 days followed by rewatering to 50% of the dry soil weight for another 3 days). The effects of the drought and rehydration treatments on leaf succulence, phytohormones, and phytohormonal signal transduction in I. difengpi plants were investigated. In experiment II, exogenous abscisic acid (ABA, 60 mg L-1) and zeatin riboside (ZR, 60 mg L-1) were sprayed onto DS-treated plants to verify the roles of exogenous phytohormones in alleviating drought injury. Leaf succulence showed marked changes in response to the DS and DS-R treatments. The relative concentrations of ABA, methyl jasmonate (MeJA), salicylic acid glucoside (SAG), and cis-zeatin riboside (cZR) were highly correlated with relative leaf succulence. The leaf succulence of drought-treated I. difengpi plants recovered to that observed with the CK treatment after exogenous application of ABA or ZR. Differentially expressed genes involved in biosynthesis and signal transduction of phytohormones (ABA and JA) in response to drought stress were identified by transcriptomic profiling. The current study suggested that the phytohormones ABA, JA, and ZR may play important roles in the response to severe drought and provides a preliminary understanding of the physiological mechanisms involved in phytohormonal regulation in I. difengpi, an endemic, medicinal, and highly drought-tolerant plant found in extremely small populations in the karst region of South China.
摘要：
八角（五味子科），这是一种地方病，药用,以及在喀斯特山区的小而孤立的种群中发现的濒危物种，已经发展了适应干旱环境的策略，因此是探索对严重干旱的耐受机制的极好材料。在实验I中,I.地风皮植物进行了三种土壤浇水处理(CK，以50%的土壤干重充分浇水处理18天；DS，以10%的土壤干重进行干旱胁迫处理18天；DS-R，以10％的土壤干重进行干旱再水化处理15天，然后再浇水至50％的土壤干重3天）。干旱和复水处理对叶片多汁性的影响,植物激素,研究了I.迪风皮植物中的植物激素信号转导。在实验二,外源脱落酸(ABA，60毫克L-1）和玉米素核苷（ZR，将60mgL-1）喷洒在DS处理的植物上，以验证外源植物激素在减轻干旱伤害中的作用。叶片肉质性对DS和DS-R处理的响应显示出明显的变化。ABA的相对浓度，茉莉酸甲酯（MeJA），水杨酸葡糖苷（SAG），顺式玉米素核苷（cZR）与相对叶片多汁性高度相关。在外源施用ABA或ZR后，干旱处理的I.difengpi植物的叶片多汁性恢复到CK处理观察到的水平。通过转录组学分析鉴定了参与植物激素（ABA和JA）对干旱胁迫的生物合成和信号转导的差异表达基因。目前的研究表明，植物激素ABA，JA,和ZR可能在应对严重干旱中发挥重要作用，并初步了解了地风皮中植物激素调节的生理机制，一种地方病，药用,以及在华南喀斯特地区极小种群中发现的高度耐旱性植物。
