土壤颗粒对秋茄盐度效应的影响

研究了不同土壤颗粒和海水盐度条件下秋茄（Kandelia candel)幼苗生长、净光合速率和蒸腾速率的变化。海水盐度能抑制秋茄幼苗叶片的净光合速率和蒸腾速率，但可以通过增加叶片面积以促进秋茄幼苗的生长和干物质生产，其中50％海水处理大于100％海水处理。土壤颗粒对100％海水浓度下秋茄幼苗的生长有显著的影响，颗粒越小，秋茄幼苗的生长越快，干物质生产越多，但在50％海水浓度下，土壤颗粒的影响不明显，在同一海水浓度下，土壤颗粒对海水盐度抑制秋茄幼苗叶片的净光合速率和蒸腾速率的影响作用不大。颗粒越小，土壤吸收的盐离子越多，Na^ 和H^ 的交换量越大，因此降低了秋茄幼苗根系周围的盐分含量， 有效缓解高盐胁迫对秋茄幼苗生长的影响。

Influence of Soil Particle on Salt Effect of Kandelia candel Seedling

Growth, net photosynthetic rate and transpiration rate of Kandelia candel seedlings were studied under different soil type and seawater concentration treatment. Salts could inhibit leaf net photosynthetic rate and transpiration rate, but enhanced growth and dry matter production of K. candel seedlings by increasing leaf area. The promotion effect was more large in 50% seawater treatment than in 100% seawater treatment. Soil particle had a distinguished effect on growth of K. candel seedlings under 100% seawater treatment. K. candel seedlings grew more fast and had more dry matter production in Vermiculite soil with small particle than that in soil with big particle. However, no effect existed under 50% seawater treatment. Under same seawater treatment, soil particle had little effect on the inhibition of salts to leaf net photosynthetic rate and transpiration rate of K. candel seedlings. Soil with small particle could absorb more salt ions, increase more exchange of Na + and H +, so it could decrease salt ions content around root system, and lessened the effect of high salt stress on growth of K. candel seedlings.