Santos Claudiana M Dos, Endres Laurício, Ferreira Vilma M, Silva José V, Rolim Eduardo V, Wanderley Humberto C L
Laboratório de Fisiologia Vegetal, Centro de Ciências Agrárias, Universidade Federal de Alagoas, Campus Delza Gitaí, BR 104 Norte, Km 85, 57072-900 Rio Largo, AL, Brazil.
Laboratório de Fisiologia Vegetal, Universidade Federal de Alagoas, Campus Arapiraca, Av. Manoel Severino Barbosa, s/n, Bom Sucesso, 57309-005 Arapiraca, AL, Brazil.
An Acad Bras Cienc. 2017 Oct-Dec;89(4):3015-3029. doi: 10.1590/0001-3765201720160729. Epub 2017 Dec 7.
Castor bean is one of the crops with potential to provide raw material for production of oils for biodiesel. This species possess adaptive mechanisms for maintaining the water status when subjected to drought stress. A better understanding these mechanisms under field conditions can unravel the survival strategies used by this species. This study aimed to compare the physiological adaptations of Ricinus communis (L.) in two regions with different climates, the semi-arid and semi-humid subject to water stress. The plants showed greater vapor pressure deficit during the driest hours of the day, which contributed to higher values of the leaf temperature and leaf transpiration, however, the VPD(leaf-air) had the greatest effect on plants in the semi-arid region. In both regions, between 12:00 p.m. and 2:00 p.m., the plants presented reduction in the rates of photosynthesis and intracellular CO2 concentration in response to stomatal closure. During the dry season in the semi-arid region, photoinhibition occurred in the leaves of castor bean between 12:00 p.m. and 2:00 p.m. These results suggest that castor bean plants possess compensatory mechanisms for drought tolerance, such as: higher stomatal control and maintenance of photosynthetic capacity, allowing the plant to survive well in soil with low water availability.
蓖麻是一种有潜力为生物柴油生产提供油类原料的作物。该物种具有在干旱胁迫下维持水分状况的适应机制。在田间条件下更好地了解这些机制可以揭示该物种所采用的生存策略。本研究旨在比较蓖麻在半干旱和半湿润这两个不同气候区域且遭受水分胁迫时的生理适应性。在一天中最干燥的时段，植株表现出更大的蒸汽压亏缺，这导致叶片温度和叶片蒸腾作用的值更高，然而，（叶 - 气）蒸汽压亏缺对半干旱地区的植株影响最大。在两个区域，下午12点到2点之间，由于气孔关闭，植株的光合作用速率和细胞内二氧化碳浓度均出现下降。在半干旱地区的旱季，下午12点到2点之间蓖麻叶片发生了光抑制。这些结果表明，蓖麻植株具有耐旱的补偿机制，例如：更高的气孔控制能力和光合能力的维持，使植株能够在低水分可利用性的土壤中良好生存。
