CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, People's Republic of China.
University of Chinese Academy of Sciences, Beijing, 100039, People's Republic of China.
Sci Rep. 2018 Apr 4;8(1):5644. doi: 10.1038/s41598-018-24038-2.
Alnus cremastogyne, a broad-leaved tree endemic to south-western China, has both commercial and restoration importance. However, little is known of its morphological, physiological and biochemical responses to drought and phosphorous (P) application. A randomized experimental design was used to investigate how drought affected A. cremastogyne seedlings, and the role that P applications play in these responses. Drought had significant negative effects on A. cremastogyne growth and metabolism, as revealed by reduced biomass (leaf, shoot and root), leaf area, stem diameter, plant height, photosynthetic rate, leaf relative water content, and photosynthetic pigments, and a weakened antioxidative defence mechanism and high lipid peroxidation level. However, the reduced leaf area and enhanced osmolyte (proline and soluble sugars) accumulation suggests drought avoidance and tolerance strategies in this tree. Applying P significantly improved the leaf relative water content and photosynthetic rate of drought-stressed seedlings, which may reflect increased anti-oxidative enzyme (superoxide dismutase, catalase and peroxidase) activities, osmolyte accumulation, soluble proteins, and decreased lipid peroxidation levels. However, P had only a slight or negligible effect on the well-watered plants. A. cremastogyne is sensitive to drought stress, but P facilitates and improves its metabolism primarily via biochemical and physiological rather than morphological adjustments, regardless of water availability.
中国西南特有的桤木属植物桤木具有商业和恢复的重要性。然而，人们对其形态、生理和生化对干旱和磷（P）应用的响应知之甚少。本研究采用随机实验设计，研究了干旱对桤木幼苗的影响，以及 P 应用在这些响应中的作用。干旱对桤木的生长和代谢有显著的负面影响，表现为生物量（叶、茎和根）、叶面积、茎直径、株高、光合速率、叶相对含水量和光合色素减少，抗氧化防御机制减弱，脂质过氧化水平升高。然而，减少的叶面积和增强的渗透调节物质（脯氨酸和可溶性糖）积累表明，该树种具有干旱逃避和耐受策略。施加 P 显著提高了干旱胁迫下幼苗的叶相对含水量和光合速率，这可能反映了抗氧化酶（超氧化物歧化酶、过氧化氢酶和过氧化物酶）活性、渗透调节物质积累、可溶性蛋白增加和脂质过氧化水平降低。然而，P 对水分充足的植物只有轻微或可以忽略不计的影响。桤木对干旱胁迫敏感，但 P 主要通过生化和生理途径而不是形态调整来促进和改善其代谢，而与水分供应无关。
