6个树种1年生枝木质部的水力特征及与栓塞修复能力的关系

doi:10.11707/j.1001-7488.20170306

摘要/Abstract

摘要： [目的] 植物木质部栓塞修复能力已成为植物抗旱性研究的热点。本研究探讨6个耐旱树种木质部水力特征及与栓塞修复能力之间的关系，以及决定栓塞修复能力的主要影响因子，为筛选抗旱树种提供理论依据。[方法] 以西北农林科技大学博览园内生长良好的6个耐旱树种（刺槐、沙棘、榆树、元宝枫、旱柳、榛）的1年生枝为研究对象，采用Cochard Cavitron离心机诱导木质部栓塞，构建6个树种的木质部栓塞脆弱曲线，得到其栓塞脆弱性（P₅₀）值，同时测定枝条的木质部水力直径（D_h）、黎明前木质部水势及自然状态下栓塞程度（NPLC），利用低压液流计及染色法测定已栓塞枝条不同时段（20，40，60，80，100 min）的栓塞修复程度（1-PLC），进而探究不同树种木质部栓塞修复能力与栓塞脆弱性、水力直径、黎明前水势和NPLC间的关系。[结果] 1）6个树种栓塞脆弱性大小依次为刺槐>榆树>沙棘>旱柳>榛>元宝枫，其中元宝枫的抗栓塞能力最强；水力直径依次为刺槐>榆树>榛>沙棘>旱柳>元宝枫。2）用染色法测得的木质部栓塞修复程度与低压液流计测得的木质部栓塞修复程度相一致（回归方程是y=1.047x-7.567，R²=0.863）；低压液流计法测定的值完全可以反映在不同时间段栓塞枝条的修复状况。3）6个树种1年生枝木质部栓塞修复能力依次为刺槐>榆树>沙棘>旱柳>榛>元宝枫，植物重新供水后，木质部栓塞修复能力强的树种能迅速恢复栓塞导管的输水功能；栓塞修复能力与栓塞脆弱性大小顺序完全一致，呈显著的正相关（R²=0.980），即木质部栓塞脆弱性大的树种，其栓塞修复能力也越强；回归分析表明，6个树种木质部水力直径、黎明前水势和NPLC与栓塞修复能力有很强的相关性（R²分别为0.868，0.740，0.741）。[结论] 植物木质部水力特征与栓塞修复能力密切相关，特别是木质部栓塞脆弱性（P₅₀）和水力直径与栓塞修复能力有很强烈的正相关，是决定栓塞修复能力的主要影响因子。

关键词: 栓塞修复, 木质部水力特性, 栓塞脆弱性, 水力直径

Abstract: [Objective] Drought has become a key factor affecting plant growth in the world. Hence, it is necessary to study the xylem embolism and refilling. The aim of this study was to explore the relationship between hydraulic traits and embolism refilling in the xylem of six tree species, to elucidate the influence of xylem hydraulic traits on the embolism refilling, and to provide theoretical evidence for screening drought-resistant tree species.[Method] Six well-growing tree species, Robinia pseudoacacia, Hippophae rhamnoides, Ulmus pumila, Acer truncatum, Salix matsudana and Corylus heterophylla were studied. Cochard Cavitron centrifuge was used to induce xylem embolism of one-year-old twigs when percentage loss of conductivity was higher than 95%. The "vulnerability curves" of six tree species were plotted to obtain the mean value of P₅₀. The recovery level of different periods (20, 40, 60, 80, 100 min) was measured by Low Pressure Flow Meter with multi-channels and staining methods. At the same time, the hydraulic diameter, pre-dawn water potential of xylem and natural percentage loss of conductivity (NPLC) were measured.[Result] 1) The order of the average P₅₀ values of the six species was R. pseudoacacia > U. pumila > H. rhamnoides > S. matsudana > C. heterophylla > A. truncatum, and A. truncatum was the most drought-tolerant tree species; 2) The recovery level of the xylem embolism by staining method was consistent with embolism recovery level by Low Pressure Flow Meter. The regression equation was y=1.047x-7.567, R²=0.863. The LPFM method can completely reflect the recovery level of the embolism branches in different time periods; 3) The xylem embolism recovery capacity of the six tree species was ranked as follows:R. pseudoacacia > U. pumila > H. rhamnoides > S. matsudana > C. heterophylla > A. truncatum. This implies that tree species with the high recovery ability of xylem embolism can quickly restore the function of transporting water when the plants are resupplied with water. The results showed that the order of the abilities of xylem embolism refilling was completely consistent with the order of embolism vulnerabilities. The ability of embolism refilling increased with embolism vulnerability (R²=0.980). Regression analysis indicated that the ability of embolism refilling of the six tree species was strongly correlated with hydraulic diameter, pre-dawn water potential of xylem, NPLC, with values of R² of 0.868, 0.740, 0.741, respectively.[Conclusion] The hydraulic traits of xylem were closely related to the refilling ability of xylem embolism. In particular, there was a strong positive correlation among P₅₀, hydraulic diameter and the ability to recover from embolism. Therefore, P₅₀ and hydraulic diameter were the main influencing factors for embolism refilling.

Key words: embolism refilling, hydraulic traits of xylem, embolism vulnerability, hydraulic diameter

中图分类号:

S718.46

党维, 姜在民, 李荣, 张硕新, 蔡靖. 6个树种1年生枝木质部的水力特征及与栓塞修复能力的关系[J]. 林业科学, 2017, 53(3): 49-59.

Dang Wei, Jiang Zaimin, Li Rong, Zhang Shuoxin, Cai Jing. Relationship between Hydraulic Traits and Refilling of Embolism in the Xylem of One-Year-Old Twigs of Six Tree Species[J]. Scientia Silvae Sinicae, 2017, 53(3): 49-59.

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