广东连州田心梅树冲伯乐树种群及其生境特征

伯乐树是国家Ⅰ级重点保护野生植物，其自然种群在广东连州田心梅树冲的个体数量较多。2013年用HOBO温湿度记录仪对其生境温湿度进行监测，同时测定土壤的理化特性、叶面光照强度、叶片生理生态特性、种群结构等，以分析伯乐树种群及其群落的生境特征。结果表明，生境2013年的年均气温17.356℃，年均相对湿度92.002％，符合中国伯乐树生境年均气温15℃以上，相对湿度80％以上的条件；土壤pH为6.38，有机质含量为0.50％，所测得的叶面光照强度小于旷地的10％。叶片SPAD值40.81-45.73，净光合速率3.53-4.07μmol/（m2·s）（以CO2计），蒸腾速率0.90-1.40 mmol/（m2· s）（以H2O计），水分利用效率2.91-3.92。2012年和2013年伯乐树种群为Poisson分布型；年龄结构、地径结构和树高结构均呈纺锤形，表明因受2008年初南岭地区冰雪灾害的影响，大树和更新层幼苗均受到破坏，为衰退种群。

Characteristics of Bretschneidera sinensis Population and Its Habitat at Meishuchong,Tianxin Provincial Nature Reserves of Guangdong

Bretschneidera sinensis is a national key protected species of grade Ⅰin China and there is a lager popu-lation at Meishuchong, Tianxin, Lianzhou, Guangdong.By using an automatic onset HOBO mini-weather sta-tion, the air temperature and the air relative humidity were monitored for one year in 2013 at the habitat of B.sinensis.The soil physic-chemical characteristics , the light intensity on leaf , and the eco-physiological indexes of B.sinensis leaf, the population structures were measured during the period for analyzing the characteristics of its population .The results showed that the mean annual air temperature was 17.356℃ and the mean annual air rela-tive humidity was 92.002% at the field site , which is in the range of its best temperature 15℃, humidity of over 80 %.Soil pH of 6.38, the organic matter content of 0.50 %.The light intension on leaf was 10 % less than that of open outside of the forest .The SPAD value was from 40.81 to 45.73.The net photosynthesis rate, the transpiration rate, and water usage efficient of B.sinensis leaf were 3.53 -4.07 μmol/（ m2 · s） （ calculated by CO2）, 0.90-1.40 mmol/（m2·s）（calculated by H2O）and 2.91-3.91, respectively.The B.sinensis popula-tion was Poisson distribution pattern .The age class structure , base size class structure and height class structure were all the fusiform , and that indicates the population is a decreasing population because of the icy disaster in ear -ly 2008 in the Nanling Mount region and the big tree and young seedling were destructed during that period of time .