【摘要】 北美红桤木(Alnus rubua)是产于北美国西部太平洋沿岸的高大落叶乔木,中国林科院2003年底从美国首次引进。我们从2005年起首次系统研究了北美红桤木苗木主要光合特性,结果表明:①红桤木光合作用日变化呈现单峰与双峰曲线两种类型,在生长期(6月、7月、9月和10月)光合作用的日变化是双峰曲线,峰值出现时间上午09:00~11:00,下午13:00~14:00;在6月、10月,Pn下午峰值比上午峰值小,在7月、9月Pn第二个峰值比第一个峰值高;11月份单峰曲线,峰值出现在11:00;②不同月份、不同季节北美红桤木的Pn日变化呈现不同特征。以11月份Pm ax最大20.3μmol/(m2.s),9月份次之14.6μmol/(m2.s);③北美红桤木光补偿点很低,介于7.52~51μmol/(m2.s),②、③说明北美红桤木利用弱光的能力强;④北美红桤木羧化效率为0.026 9~0.048 3,以9月份的羧化效率最高,7月份的最低;其中上部叶>侧枝叶,与台湾桤木的羧化效率(0.027 0~0.046 8)接近;CO2补偿点为49.35~117.95与四川桤木接近,属C3植物。更多还原

【Abstract】 Alnus rubua is a deciduous species which was produced in the western Pacific coast of the North American.Alnus rubua was introduced first time from United States by Chinese Academy of Forestry in end of 2003.The first systematic study of photosynthetic characteristics of seedling of Alnus rubua was started in 2005.The results showed: ① The photosynthesis changes in a day of Alnus rubua were displayed two types of single peak with the double curve.The changes photosynthesis was the double curve in the growth period（June,July,September and October）,the peak hours from 9:00 am～11:00 am and 13:00 pm ～14:00 pm.The Pn in the afternoon was smaller than the morning peak in June and October.The Pn second peak was higher than the first one in July and September. The single peak was in November and the peak in 11:00 am.② The Pn changes in a day of Alnus rubua was in different characteristics in different months or different season.The largest indexes Pmax was 20.3μmol/m²·s in November,and the second large indexes Pmax was 14.6μmol/m²·s in Septermber.③ The light compensation point of Alnus rubua was lower and ranging from 7.52μmol/m²·s to 51μmol/m²·s.The results of ② and ③ showed that the strong ability in using low light.④ The wood carboxylation efficiency of Alnus rubua was in 0.0269～0.0483.The maximum carboxylation efficiency was in September and minimum in July.The upper leaves was higher than the side branches.The carboxylation efficiency of Alnus rubua was similar with Alnus formosana（0.0270～0.0468）.The CO₂ compensation point was 49.35～117.95 and similar with Alnus cremastogyne,is a C₃ plant.更多还原