NEIKER-TECNALIA, Department of Biotechnology, Vitoria-Gasteiz E-01080, Spain.
Tree Physiol. 2013 Jan;33(1):69-80. doi: 10.1093/treephys/tps125.
Drought is one of the main abiotic factors that determine forest species growth, survival and productivity. For this reason, knowledge of plant drought response and the identification of physiological traits involved in stress tolerance will be of interest to breeding programs. In this work, several Pinus radiata D. Don breeds from different geographical origins were evaluated along a water stress period (4 weeks) and subsequent rewatering (1 week), showing different responses among them. Leaf water potential (Ψ(leaf)) and osmotic potential decreases were accompanied by a variation in the total relative water content (RWC, %). The most tolerant breeds presented the lowest leaf water potential and RWC at turgor loss point, and showed the lowest elastic modulus (ε) values. A high ε value was a characteristic of a less-drought-tolerant plant and was related to membrane alterations (high electrolyte leakage percentages) that could favor cell water loss. Of the group of solutes that contributed to osmotic adjustment, soluble carbohydrates were the most abundant, although stressed plants also increased their content of free amino acids [mainly proline (Pro) and glutamic acid (Glu), and γ-aminobutyric acid (GABA)] and free polyamines. In addition, the most sensitive breeds had a higher GABA/Glu ratio. After rewatering, Pro and GABA were higher in rehydrated plants than in controls.
干旱是决定森林物种生长、存活和生产力的主要非生物因素之一。因此，了解植物的干旱响应以及确定与胁迫耐受相关的生理特征将是育种计划感兴趣的内容。在这项工作中，对来自不同地理起源的几个辐射松 D. Don 品种进行了评估，这些品种经历了一个水分胁迫期（4 周）和随后的再浇水期（1 周），它们之间表现出不同的响应。叶水势（Ψ（leaf））和渗透势的降低伴随着总相对含水量（RWC，%）的变化。最具耐受性的品种在膨压损失点时表现出最低的叶水势和 RWC，并且表现出最低的弹性模量（ε）值。高 ε 值是一种对干旱耐受性较低的植物的特征，并且与可能导致细胞失水的膜改变（高电解质泄漏百分比）有关。在对渗透调节有贡献的溶质中，可溶性碳水化合物最为丰富，尽管受胁迫的植物也增加了游离氨基酸的含量[主要是脯氨酸（Pro）和谷氨酸（Glu）以及γ-氨基丁酸（GABA）]和游离多胺。此外，最敏感的品种具有更高的 GABA/Glu 比值。再浇水后，复水植物中的 Pro 和 GABA 含量高于对照。
