马尾松茎木质部产生与水热关系的初报

A Preliminary Study of the Relationships between the Activity of Stem Cambium Forming Xylem and Rainfall and Temperature inPinus massoniana

在马尾松年生长周期中，定位逐月采样，比较解剖形成层活动的数量和产生木质部的结构与旬均温和旬雨量的关系．纺锤状原始细胞的分裂次数明显受温度控制，在月均温１３．５～２９．３℃的活动期中，以１７．１～２７．８℃分裂较快，并有一定抗旱性；在连续旬雨量１０ｍｍ以下，仍能形成纺锤状细胞．管胞分化的下限温度约１１℃，雨量是调节管胞腔径及壁、腔比值变化的主要因素．木射线细胞的生长受管胞结构的影响，其长和宽的扩大分别随管胞腔径和壁、腔比值提高而增加，在正常温度范围内，间隔性干旱有促进树脂道的形成．

In this paper,the relationship between numbers of active cambium,xylem structure and the mean temperature and mean rainfall Per 10-day period were found out by means of comparative anatomy,with the materials being sampled from given spots monthly in the yearly growth cycle of Pinus massoniana. The main results showed that times of the division of fusiform initial cells was evidently affected by temperature;that fusiform initial cells divided more rapidly in the temperature range of 17.1 to 27.8℃ in the active stage of monthly mean temperature varying from 13.5 to 29.3℃,during which plants somwhat perform the resistance to drought and fusiform initial cells could be formed even the mean rainfall per 10-day period was continuous ly below 10mm,with the lower critical temperature for tracheid differentiation being about 11℃;that rainfall was the one of major factors which regulated the diameter of tracheid lumen and the ratio of wall thickness to lumen diameter of tracheid;that the growth of xylem ray cells was influenced by the structure of tracheid and the cells expanded as the diameter of tracheid lumen and the ratio of wall thickness to lumen diameter of tra cheid increased;and that within normal temperature range,interval drought was help full to the formations of resin passages.