<正>原产地广西的马尾松种子，４月下旬在南京播种育苗，１０月中旬以２５和５０ｍｇ·Ｌ￣（－１）多效唑溶液淋灌处理，对松苗越冬有良好的效应，尤以５０ｍｇ·Ｌ￣（－１）处理的效果较为明显。在越冬期间多效唑处理苗的电解质渗漏率低于对照，超氧物歧化酶与吲哚乙酸氧化酶活性比对照显著增强，接近于抗寒性强的江苏种源马尾松苗。此外，多效唑处理苗的可溶性糖含量及生物量（包括根和茎叶的鲜重、干重）均明显高于对照，而五个月的高生长增加量仅为对照的７９％和５５％。

Seeds of pinns massoniana Lamb.(masson pine) from Guangxi were sown in Nanjing on April 25, 1992. The seedlings were treated with 25 and 50 mg. L-1 Paclobutrazol(PP_(333)) on October 19, during the winter time. It was shown that the electrolytic leakage of PP_(333) treated seedling leaves was decreased, the activity of superoxide dismutase(SOD) and the content of water-soluble sugar were increased. Moreover, in early spring, the activity of lAAoxidase in PP_(333) treated leaves was promoted obviously. PP_(333)(25. 50 mg. L-1) could retard the height of seedlings in the field esperiment. The fresh and dry weight of treated seedlings were superior to the control and the effects of 50 mg. L-1 were much stronger than that of 25 mg. L-1. These results suggest that 50 mg. L-1 PP_(333) can enhance the resistance of masson pine seedlings under low temperatures.