不同泡桐品种(种源)埋根苗生长与光合特性分析

为进一步研究泡桐埋根苗生长发育动态与光合特性之间的关系,以在郑州地区生长良好的4个泡桐品种(种源)埋根苗为研究材料,对1年生埋根苗生长期的苗高、地径、净光合速率、气孔导度、胞间CO2浓度、蒸腾速率等指标变化动态进行分析。结果表明:不同泡桐品种(种源)埋根苗的苗高生长和地径生长的季节变化趋势基本一致,苗高生长的快速生长期在7月中旬到8月下旬,9月为生长缓慢期,10月初到10月中旬苗高生长基本停止;地径生长的快速生长期从7月中旬到9月初,9月中下旬到10月为缓慢生长期,但10月下旬地径仍然还在缓慢生长,即泡桐地径生长比苗高生长延长10~15 d。不同泡桐品种(种源)埋根苗净光合速率、胞间CO2浓度、气孔导度、蒸腾速率4个光合指标在不同月份的日变化规律比较一致,胞间CO2浓度的日变化均呈现出先下降后上升的单谷曲线特征;净光合速率、蒸腾速率、气孔导度均在6、8、10月份出现双峰现象,且峰值出现时间较为一致,说明几个指标呈正相关;毛白33、9502的净光合速率相对较高,郑州白花的值相对较小,与生长量的表现一致;总体来看,5、10月份各泡桐品种(种源)无性系埋根苗的净光合速率偏低,6、7、8、9月份则相对较高,显示了泡桐在不同月份光合能力大小的差异。

Growth and Photosynthetic Characteristics of Buried Root Seedlings of Different Paulownia Varieties

In order to investigate the relationship between the growth and photosynthetic characteristics of Paulownia buried root seedlings,the buried root seedlings of 4 Paulownia varieties which grew well in Zhengzhou area were used as research materials,and the dynamic changes of seedling height,diameter,Pn,Gs,Pr,Ci of 1-year-old Paulownia seedlings in the growth period were measured.Tthe results showed that the seasonal variation trends of the height and diameter growth of seedlings of different Paulownia varieties were similar.The fast growing period was from mid July to late August for height growth,the slow growth period was September,and height growth stopped from early October to mid October.While the fast growth period of diameter growth was from mid July to early September,and the slow growth period was from mid-late September to October,but diameter still slow grew in late October.It showed that the growth time of diameter growth of Paulownia was 10-15 d longer than that of height growth.The diurnal curves of four photosynthetic factors (Pn,Gs,Tr and Ci) of seedings of different Paulownia varieties were the same.The diurnal variation of Ci showed the characteristics of the single valley curve that first decreased and then increased.The diurnal variation of Pn,Gs and Tr was bimodality in June,August and October,and the time of the peak appearance was consistent,which showed that there was a positive correlation between the several indexes.Pn of MB33 and 9502 was relatively higher and ZHb'was smaller,which was consistent with the performance of growth.On the whole,Pn of Paulownia was low in May and October,but was relatively high in June,July,August and September,which showed that there were difference in the photosynthetic capacity of Paulownia in different months.