Investigation of Exogenous Benzyladenine on Growth, Biochemical Composition, Photosynthesis and Antioxidant Activity of Indian Sandalwood (Santalum album L.) Seedlings

摘要

Cytokinins play essential roles in many aspects of plant growth and development. To study the effects of benzyladenine (BA) on growth and metabolism of Indian sandalwood (Santalum album L.) seedlings, the influences of BA concentrations of 0, 1, 10 and 100 mgL(-1) on growth, biochemical components (proteins, sugars, chlorophylls and carotenoids) and gas exchange parameters as well as oxidative status were investigated through a pot cultivation experiment. The results showed that BA acted in a biphasic manner. Treatment with BA at 1 mgL(-1) promoted stem growth, crown width and dry biomass accumulation, improved seedling quality, enhanced the net photosynthetic rate and instantaneous water use efficiency and stimulated photosynthetic pigment (chlorophyll a, chlorophyll b and carotenoid) accumulation greatly. Moreover, the contents of soluble proteins and sugars were also increased, but the height growth was inhibited considerably. Meanwhile, the activities of most antioxidant enzymes (catalase, peroxidase and superoxide dismutase) were also strengthened significantly, and therefore lipid peroxidation was inhibited greatly. In contrast, no significant improvement was observed on ground diameter, crown width, biomass, quality index, chlorophyll a content, chlorophyll b content or net photosynthetic rate when treated with 10 and 100 mgL(-1) BA, but the oxidative status was aggravated, as a result of which lipid peroxidation was intensified. The data proved that BA was one of the most active plant growth regulators on growth and metabolism of S. album seedlings, and suggested that leaf application of 1mgL(-1) BA was the most suitable concentration for enhancing seedling quality during the nursery period.