桃幼树光合年变化及落叶期早晚与营养生长的关系

试验以2个桃品种(南方早红和大久保)1 a生幼树为试材,研究了光合年变化和落叶期早晚与营养生长的关系。结果表明,2个品种桃6月份光合速率日变化呈双峰曲线,最高峰在11:00,次峰在14:00—15:00;8月份光合速率曲线呈单峰,最高峰在13:00。日光合总量的季节变化也呈双峰,分别在5月和8月。4—8月南方早红单位面积月光合总量占年总量的94.15%,大于大久保同时期的比值。南方早红落叶晚于大久保,且抽生新梢能力强于大久保。因而,南方早红9—10月光合面积的增大对单株年光合总量增加的贡献略高于大久保。实验认为,南方早红4—8月高的光合能力和9—10月落叶期晚对其旺盛的营养生长都具有重要的促进作用。

Study on the relationship among seasonal variation of photosynthetic characteristics, defoliation and vegetative growth of young peach trees

The relationship among seasonal variation of photosynthesis characteristics,defoliation and vegetative growth of two 1-year-old trees of Nanfangzaohong [Prunus persica(L.) Batsch] and Okubo [P.persica(L.) Batsch.] peach cultivars were studied.The results showed that the curve of diurnal variation of photosynthesis in June showed two peaks,occurring at 11:00 and 14:00 or 15:00,respectively;and only one peak at 13:00 was found in August.The curve of seasonal variation of total Pn in one day had two peaks,occurring in May and August.Total Pn per leaf area of Nanfangzaohong from April to August accounted for 94.15% of the all year,higher than that of Okubo in the same period.Because of late defoliation and vigorous growth of shoot,photosynthetic area of Nanfangzaohong was larger than Okubo.The percentage of period from September to October to all year of total Pn per leaf area in Nanfangzaohong was higher than Okubo in the same period.It is believed that the higher photosynthesis accumulation during period from April to August and late defoliation gave a huge contribution to vegetative growth of Nanfangzaohong cultivar.