木麻黄浸提液对榄仁树幼苗生长及生理生化的影响

该研究试图将榄仁树引入木麻黄海防林以期形成混交林型的海防林。以15 d榄仁树种子苗为材料,分别采用浓度为125 g·L~-1的木麻黄根、木麻黄凋落物和林下表层土壤的水浸提液胁迫处理榄仁树幼苗60 d,研究木麻黄化感作用对榄仁树幼苗生长、光合作用、膜系统伤害、抗氧化系统酶活性及游离Pro含量的影响。结果表明:木麻黄根、木麻黄凋落物及林下表层土壤的水浸提液都能降低榄仁树幼苗的存活率,影响幼苗株高、叶和根生物量,可以推断不同浸提液中对影响植物生长成分的浓度有所不同。3种浸提液均显著降低处理15~45 d期间幼苗的净光合速率(Pn)、气孔导度(Ccond)、胞间CO_2浓度(Ci)、蒸腾速率(Tr),且显著增加幼苗水分利用率(WUE)。第60天时3种木麻黄浸提液能显著增加幼苗叶片、根的Pro含量,使得幼苗根系组织细胞膜通透性增加,而木麻黄根浸提液能显著增加幼苗Ccond、Ci、叶SOD、根CAT含量,木麻黄凋落物浸提液能显著增加幼苗Ccond和Tr,同时凋落物浸提液会显著降低幼苗根POD含量。榄仁树幼苗通过调整自身的生理生化能适应木麻黄化感胁迫的影响,为此可考虑榄仁树作为沿海防护林建设的树种之一。

Effects of leachates from Casuarina equisetifolia on growth and physiological and biochemical characteristics of Terminalia catappa seedlings

In this study, we tried to introduce Terminalia catappa into coastal Casuarina equisetifolia windbreak to form mixed forest as windbreak, so as to improve efficiency of wind sheltering and sand fixation and the regional ecological environment. We selected Terminalia catappa of seedling age of 15 d as experimental and irrigate allelochemicals of leachates of Casuarina equisetifolia of concentration of 125 g·L^-1 from roots, rhizosphere soil and litter, and studied the effects of allelopathy of C. equisetifolia on growth, photosynthesis, the damage of membrance system, antioxidant enzyme activity system and proline content of T. catappa seedlings in growing period of 60 d. The results showed that the leachates of roots, litter and rhizosphere soil reduced the survival rates and damaged seedlings of the beginning of the treatment, and significantly affected the plant height, leaves, roots biomass of Terminalia catappa seedlings. Therefore, we could deduce that influence plant growth by the composition of different leachates of Casuarina equisetifolia. All the three leachates significantly reduced the net photosynthesis(Pn), stomatal conductance(Ccond), inter cellular CO₂ concentration(Ci),transpiration rate(Tr), but significantly increased the water use efficiency(WUE)of the seedlings after 15-45 d since the treatment beginning. No significant effect of leachates from C. equisetifolia on the leaf chlorophyll contents of Terminalia catappa seedling of treatment beginning, with the prolong of growth period, but the roots leachates of C. equisetifolia significantly reduced chlorophyll content of seedling. The seedlings growth period of 60 d, all the three leachates significantly increased the cell membrane penetrability and proline content(Pro), but the roots leachate significantly increased the stomatal conductance, inter cellular CO₂ concentration, superoxide dismutase in leaves and catalase in roots of T. catappa. The litter leachates increased the stomatal conductance and transpiration rate, and they also reduced peroxidase content. Therefore, seedlings by adjusting its physiological and biochemical designed to the allelopathy stress of leachates of Casuarina equisetifolia, which could be used as one of tree species of the construction of the coastal shelter forest.