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本实验是为确定根系温度和土壤干旱对二年生辐射松生长的影响,在温室里的自然光照下进行的。(有50％的日光)白天温度为27℃,夜间温度为21℃。181个容器的实生苗,分别用四种根温(6°、10°、15°和20℃)以及两个土壤干旱循环进行处理(每九天或十二天之后浇灌一次)总共处理28天,大约每星期两次测量予先选定的针叶和顶梢长度。在第九日和第十二日,测定白天的环境条件和植物水分关系的模式。水蒸气的叶面传导性受根温的影响不大,但是九天和十二天的干旱循环严重地减少了气孔的开启。只有在白天,低的根温才使木质部压强降低,而土壤干旱在白天和夜间都会降低压力。根温在15℃时,针叶、顶梢和根系生长最大。虽然,低的根温在白天不会使气孔关闭以及夜间水分应力有明显的差异,但低的根温和土壤干旱都明显削弱生长。113天后试验结束,几种处理间的针叶总生长量和枝条的扩展不再有显著的差异。
This experiment was conducted to determine the effects of root temperature and soil drought on the growth of biennial radiata pine, under natural light in a greenhouse. (50% of daylight) daytime temperature is 27 ℃, night temperature is 21 ℃. A total of 181 container seedlings were treated for a total of 28 days with four root temperatures (6 °, 10 °, 15 ° and 20 ° C) and two soil drought cycles (once every nine or twelve days) Approximately twice a week the preselected conifer and tip length were measured. On day 9 and day 12, the patterns of day-to-day environmental conditions and plant-water relationships were determined. The leaf surface conductivity of water vapor is not significantly affected by root temperature, but the drought cycle of nine days and twelve days severely reduces stomatal opening. Only in the daytime, low root temperatures reduce xylem pressure and soil drought reduces stress during the day and night. Root temperature at 15 ℃, the needles, tops and roots grow the most. Although low root temperature did not cause stomatal closure during the day and significant differences in nighttime moisture stress, both low root temperature and soil drought significantly impaired growth. After 113 days, the experiment ended. There was no longer any significant difference in the total growth of needles and the extension of shoots between treatments.