文献类型：期刊文献

英文题名：Xylem structure and hydraulic characteristics of deep roots, shallow roots and branches of walnut under seasonal drought

作者：Wang, Lin[1,2] Dai, Yongxin[1,2] Zhang, Jinsong[3] Meng, Ping[3] Wan, Xianchong[2]

第一作者：Wang, Lin

通信作者：Wan, XC[1]|[a000593bf8eb71713e6fc]万贤崇;

机构：[1]Shanxi Agr Univ, Coll Forestry, Taigu 030801, Shanxi, Peoples R China;[2]Chinese Acad Forestry, Inst New Forestry Technol, Beijing 100091, Peoples R China;[3]Chinese Acad Forestry, Res Inst Forestry, Beijing 100091, Peoples R China

年份：2022

卷号：22

期号：1

外文期刊名：BMC PLANT BIOLOGY

收录：;Scopus(收录号：2-s2.0-85137904347);WOS:【SCI-EXPANDED(收录号:WOS:000853901800001)】；

基金：This study has been supported by the National Science and Technology Support Plan of China (2015BAD07B0501) to XW, Applied Basic Research Project of Shanxi Province (201801D121246) to LW. The funders did not participate in this study except providing fundings.

语种：英文

外文关键词：Xylem anatomy; Vulnerability to cavitation; Deep and shallow roots; Mechanism of embolism repair; Xylem conduits; Hydraulic conductivity; Dry and wet season

摘要：Background Despite the importance of root hydraulics, there is little research on the in situ dynamic responses of embolism formation and embolism repair of roots distributed in different soil depths in response to different water regimes. Results The vessel diameter, hydraulic conductivity, and vulnerability to cavitation were in the order of deep root > shallow root > branch. The midday PLC of shallow root was the highest in the dry season, while the midday PLC of deep root slightly higher than that of branch with no significant difference in the two seasons. The capacity of embolism repair of roots was significantly greater than that of branch both in dry season and wet season. The xylem pressure was in the order of deep roots > shallow root > branch, and it was negative in most of the time for the latter two in the dry season, but positive for both of the roots during the observation period in the wet season. The NSC and starch content in roots were significantly higher than those in branches, especially in the dry season. In contrast, roots had lower content of soluble sugar. Conclusions The relatively stable water condition in soil, especially in the deep layers, is favorable for the development of larger-diameter vessels in root xylem, however it cannot prevent the root from forming embolism. The mechanism of embolism repair may be different in different parts of plants. Deep roots mainly depend on root pressure to refill the embolized vessels, while branches mainly depend on starch hydrolysis to soluble sugars to do the work, with shallow roots shifted between the two mechanisms in different moisture regimes. There is theoretically an obvious trade-off between conducting efficiency and safety over deep roots, shallow roots and branches. But in natural conditions, roots do not necessarily suffer more severe embolism than branches, maybe due to their root pressure-driven embolism repair and relatively good water conditions.