马尾松幼龄阶段的生长规律

<正>研究表明,马尾松幼树顶芽大小和春梢长度呈正相关。计算得出估测高生长量的Logistic方程和Ⅱ型S型曲线方程。春梢生长速率和气温的关系最为密切,适于春梢生长的旬平均气温为10～30℃,20℃左右生长速率最大。直径月生长量的季节变化与月降雨量及日平均净光合率的季节波动相一致。一年生叶的日平均净光合率于5月底达一年中最大值,7～9月由于干旱而明显下降,10月达一年中的第二峰值。

GROWTH PATTERNS OF YOUNG PINUSMASSONIANA LAMB TREES

Investigations have been made on the seasonal variation in height growth, diameter growth and net photosynthetic rates (NPR) of the needles of young Pinus massoniana Lamb. (2 to 6 years old) in Guanzhuang Forest Station, Fujian province during the years of 1983 and 1984.There exists a positive relationship between spring-shoot length and apical bud size. The growth rate of spring shoots is closely correlated to air temperatures. The air temperatures favorable to the growth of spring shoots range from 8°Cto 30°C. (the average temperature of ten days) with the highest growth rate at 20°C.The measurements made in 1983 show that the seasonal changes of diameter growth accord with the seasonal fluctuations of rainfall and NPR of needles. The average daily NPR of one-year-old needles reaches a peak value by the end of May, declines obviously from July to September due to drought, and then gets to a second peak value in October.