罗汉松科3种植物茎和根木质部水分运输、解剖结构与机械强度之间的关系  

Relationships among xylem transport, anatomical structure and mechanical strength in stems and roots of three Podocarpaceae species

作　　者：陆世通 陈森 李彦 王忠媛[1] 潘天天 叶琳峰 谢江波 LU Shi-Tong;CHEN Sen;LI Yan;WANG Zhong-Yuan;PAN Tian-Tian;YE Lin-Feng;XIE Jiang-Bo(State Key Laboratory of Subtropical Silviculture,Zhejiang A&F University,Hangzhou 311300,China;College of Forestry and Biotechnology,Zhejiang A&F University,Hangzhou 311300,China;and 3State Key Laboratory of Desert and Oasis Ecology,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Ürümqi 830011,China)

机构地区：[1]浙江农林大学省部共建亚热带森林培育国家重点实验室,杭州311300 [2]浙江农林大学林业与生物技术学院,杭州311300 [3]荒漠与绿洲生态国家重点实验室,中国科学院新疆生态与地理研究所,乌鲁木齐830011

出　　处：《植物生态学报》2021年第6期659-669,共11页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(31770651、41730638和31901280)。

摘　　要：水力失效是植物干旱死亡的主要机制。量化分析水力性状的种间和器官间差异是预测树木在气候变化下的响应甚至生存能力的基础。该研究对比分析了罗汉松科3种植物器官(茎和根)水平上水力功能性状的差异,并探讨其与解剖结构和机械强度之间的关系。在湿生同质园内选择罗汉松科3种植物,测定了茎和根木质部水力功能性状(最大比导率(K_(s))和栓塞抗性(P_(50)))、解剖结构性状(管胞直径(D_(t))、水力直径(D_(h))、管胞密度(N_(t))、管胞壁厚(T_(w))、纹孔膜直径(D_(p))和纹孔密度(N_(p)))和机械强度(木材密度(WD)和管胞厚度跨度比((t/b)^(2)))。结果发现:(1)罗汉松科3种植物茎木质部不存在效率-安全权衡,而根木质部存在权衡。(2)茎Ks与Dp显著正相关,与(t/b)^(2)和WD无关;茎P_(50)与D_(p)极显著负相关,与(t/b)^(2)和WD无关。(3)根K_(s)与D_(h)显著正相关,与Tw和(t/b)^(2)极显著负相关;根P50与Tw、(t/b)^(2)和WD均极显著正相关。在罗汉松科植物中,根木质部性状与输水效率和栓塞抗性的密切关系是解释其存在效率-安全权衡的基础,而茎木质部的过度建造是茎不存在效率-安全权衡的原因,木质部的过度建造仍需要更多的实验证据。Aims Hydraulic failure is one of the primary cause of plant mortality during drought. Thus, quantitative analysis on inter-specific and inter-organ variance in hydraulic traits can help us to predict the response and even survivability of species under climate change. Methods Here, three Podocarpaceae species(Podocarpus macrophyllus, P. macrophyllus var. maki and Nageia nagi) grown in a mesic common garden were studied, with xylem hydraulic function(specific hydraulic conductivity(K_(s));embolism resistance(P_(50))), anatomical structure(tracheid diameter(D_(t));hydraulic diameter(Dh);tracheid wall thickness(T_(w));tracheid density(N_(t));pit membrane diameter(Dp);pit density(N_(p))) and mechanical strength(wood density(WD);tracheid thickness to span ratio((t/b)^(2))) measured. Then, we analyzed hydraulic traits variance at the organ level(stem and root) in three Podocarpaceae species, and investigated the relationships among xylem hydraulic traits, anatomical structure and mechanical strength in stems and roots. Important findings We found that: 1) The stem xylem in three Podocarpaceae species exhibited no safety-efficiency trade-off. In contrast, the root xylem exhibited safety-efficiency trade-off. 2) For stems, K_(s) was positively correlated with D_(p), but decoupled with stem WD and(t/b)^(2);Stem P_(50) was negatively correlated with D_(p), but not correlated with WD and(t/b)^(2). 3) For roots, K_(s) was positively correlated with hydraulic diameter, but negatively correlated with root Tw and(t/b)^(2);Root P50 was positively correlated with Tw,(t/b)^(2) and WD. Root xylem traits exhibited strong relationships with both Ks and P_(50), demonstrating its cause-and-effect basis for the safety-efficiency tradeoff. On the other hand, the absence of safety-efficiency tradeoff in stems may be attributed to the overbuilt xylem of Podocarpaceae. More experimental evidence on the overbuilding of xylem is desired in the future study.

关 键 词：栓塞 导水率 脆弱曲线 管胞 罗汉松科 

分 类 号：Q945[生物学—植物学]