4个杨树无性系木质部导管结构与栓塞脆弱性的关系

Relationships between Xylem Vessel Structure and Embolism Vulnerability in Four Populus Clones

以杨属84K、I-101及其杂交子代02-8-21、02-9-22为研究对象,采用Cochardcavitron离心机法测定木质部栓塞脆弱性(P50),利用染色法、硅胶注射法等测定每个无性系木质部导管的直径、长度、导管壁上纹孔膜面积,探究木质部导管结构与栓塞脆弱性的关系,以期建立杨树无性系的木质部结构指标体系。结果表明:4个无性系枝条的栓塞脆弱性为02-8-21>I-101>02-9-22>84K,子代02-9-22比02-8-21抗栓塞。4个无性系的导管直径为02-8-21>02-9-22>84K>I-101,导管长度为02-9-22>02-8-21>I-101>84K,纹孔膜面积为02-8-21>02-9-22>I-101>84K。回归分析表明随着杨树无性系枝条导管直径和每个导管上纹孔面积的增大,其栓塞脆弱性也随之增大,显示出较强的正相关(R2>0.7),导管长度与栓塞脆弱性显示出较弱的相关性(R2=0.019)。导管直径大小对栓塞脆弱性起决定性作用。

In this paper, 4 Populus clones of 84K （Populus alba×P. glandulosa）, I-101（Populus alba） and their hybrid progenies 02-8-21, 02-9-22 were studied. We used Cochard cavitron centrifuge to determine embolism vulnerability（P50）, and staining as well as silicone injection techniques to measure vessel diameter, vessel length and pit area per vessel of the four clones. The aim is to probe into the relationship between embolism vulnerability and vessel structure, and to establish xylem structure index system of poplar clones. The results showed that the sensitivity of xylem embolism to water potentials of the four clones was ranked as：02-8-21I-10102-9-2284K, and hybrid progeny 02-9-22 was more resistant to embolism than 02-8-21. The order of vessel diameter size of the four clones was 02-8-21 02-9-22 84K I-101, vessel length 02-9-2202-8-21 I-101 84K, pit area per vessel 02-8-21 02-9-22 I-101 84K. Regression analysis illustrated that with the vessel diameter and pit area per vessel increased, its embolism vulnerability also increased, indicating that there was a strong positive correlation （R20.7）, while vessel length had weak correlation with embolism vulnerability （R2=0.019）. Thus, vessel diameter size plays a decisive role on embolism vulnerability.