林业科学  2007, Vol. 43 Issue (9): 74-82   PDF    
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朱万泽, 王金锡, 罗成荣, 段学梅.
Zhu Wanze, Wang Jinxi, Luo Chengrong, Duan Xuemei.
森林萌生更新研究进展
Progresses of Studies on Forest Sprout Regeneration
林业科学, 2007, 43(9): 74-82.
Scientia Silvae Sinicae, 2007, 43(9): 74-82.

文章历史

收稿日期:2006-08-31

作者相关文章

朱万泽
王金锡
罗成荣
段学梅

森林萌生更新研究进展
朱万泽1, 王金锡2, 罗成荣2, 段学梅2     
1. 中国科学院成都山地灾害与环境研究所 成都 610041;
2. 四川省林业科学研究院 成都 610081
摘要: 综述森林萌生更新形成的6种假说:生物地理假说、生境假说、营养假说、干扰假说、资源分配假说和激素调控假说,并指出今后应加强森林萌生更新的群落生态学和生理生态适应性研究,以及萌生更新在森林植被恢复和生态重建中的应用研究。
关键词:萌生更新    生理生态机理    持续生态位    干扰    
Progresses of Studies on Forest Sprout Regeneration
Zhu Wanze1, Wang Jinxi2, Luo Chengrong2, Duan Xuemei2     
1. Institute of Mountain Harzard and Environment, Chinese Academy of Sciences Chengdu 610041;
2. Sichuan Forestry Academy Chengdu 610081
Abstract: Sprouting is a part of the "regeneration niche" and a highly evolutionarily labile trait for plants. Sprout regeneration is an efficient mechanism for forest regeneration to regain lost biomass after disturbances, and has the important ecological function in regulating individual life history strategies of plants, and restoring secondary vegetation following intense disturbances, as well as maintaining species composition and structure of community. Sprouting is a complex ecophysiological process. The sprouting ability of plant is not only affected by its exterior habitat, disturbances and resources level, but also controlled by its interior nutrient level and hormone situation. This paper reviewed six hypotheses on the mechanism of sprout formation. The biogeographic hypothesis suggests that different biogeographic communities have different number of sprouters, and there are more sprouters in tropical forest sites than that in temperate sites. The habitat hypothesis indicates that trees in different environment have different resprouting ability. And the nutrition hypothesis considers that the soil, the coarse roots and the taproots are the main nutrient sources for sprouting. From the viewpoint of disturbance hypothesis, disturbance types, intensity and frequency are usually considered to be the important determinant of resprouting in woody communities. The resource allocation hypothesis states that resprouting requires resources for supporting sprout after disturbances such as fire or cutting. Resprouting ability is regulated by level of hormone in tree, and auxins (IAA) and cytokinins are two groups of growth regulators to promote development of stem buds and shoots in the light of hormone regulating hypothesis. Finally, some propositions in this research field were made to offer the references for further studies.
Key words: sprouting regeneration    ecophysiological mechanism    persistence niche    disturbances    

森林更新是森林群落演替和植被生态恢复的重要生态学过程。萌生是植物,尤其是木本被子植物中十分普遍的现象(Wells, 1969),是植物再生生态位(regeneration niche)的一部分(Grubb, 1977),同时也是植物高度进化的不稳定特征之一(Bond et al., 2003)。Bellingham等(2000)将木本植物的萌生分为腋生(axillary)、枝萌生(branch epicormic)、干萌生(stem epicormic)干基萌生(stem basal)以及地下茎萌生(root sprouting)等类型。森林的萌生更新主要指干基萌生和地下茎萌生,是利用树木地下茎和残留体(树桩)上的休眠芽或不定芽形成新的植株的过程,以达到森林更新的目的。由于萌生植株能通过其原有的强大根系,更有效地利用土壤中的养分资源,通常比实生植株生长快,具有更强的环境适应能力,能较快地再次占据林窗,在种群竞争中处于有利地位(Kauffman, 1991; Vesk et al., 2004a)。许多森林生态系统受萌生植株的控制,萌生更新是森林更新的重要方式。

作为一种直接的再生方式,森林萌生更新已受到越来越多的关注(Putz et al., 1989; Bellingham et al., 1994; Negrelle, 1995; Rijks et al., 1998; Kammeshedt, 1999; Bellingham et al., 2000; Bond et al., 2003; 唐勇等, 2001; 李景文等, 2005)。萌生更新在次生林保护、经营和管理中具有重要意义,在中国已广泛应用于杉木(Cunninghamia lanceolata)(马祥庆等, 2000)、杨树(Populus)(方升佐等, 2000; 卢景龙等, 2001)、水曲柳(Fraxinus mandshurica)(荆涛等, 2002)、桉树(Eucalyptus grandis× E.urophylla)(林星华, 2001)和刺槐(Robinia pseudoacacia)(董金伟等, 2001)等林业生产实践中,尤其在择伐与皆伐迹地的森林恢复和演替、苗木培育、强度择伐的天然林恢复以及人工林经营中具有重要意义(于明坚, 1999; 喻理飞等, 2002)。本文总结了森林萌生更新的生态功能,探讨了森林萌生更新形成机理,并对今后森林萌生更新研究进行了展望,以期对我国该领域的研究有所裨益。

1 萌生更新的生态功能 1.1 对个体生活史策略的影响

萌生更新在调节种子繁殖和萌生繁殖2种更新方式的平衡上具有重要意义(Bond et al., 2001; 闫恩荣等, 2005)。依靠种子难以更新的树种主要通过萌生更新来维持其种群的稳定性(Kowarik, 1995; Yamamoto et al., 1995)。一般认为,萌生能力较强的树种常常产生的种子数量较少、缺乏种子库、种子成熟率低、实生苗木较少,实生苗木保存率也较低(Kruger et al., 1997)。因此,萌生更新被当作实生更新困难树种的一种补充和适应。萌生更新对于那些种苗更新机会受到限制的物种尤为重要,是实生更新困难树种的一种补偿策略(Ohkubo et al., 1988)。英国北部的Tilia cordata群落自5 000年以前停止结实以来,几乎完全依靠萌生得以幸存下来(Pigott, 1993)。非萌生种类由于个体增加的困难,对严重干扰的抵抗能力十分脆弱,尤其是个体数量小的自交种群,干扰导致传粉树和花粉扩散途径的损失,而萌生种类能够减缓这些影响,保持种群稳定性(Higgins, 2000)。不同年龄树木的萌生能力不同,幼树的萌生能力是该树种个体补充策略的重要组成部分,而成年树的萌生能力表明其潜在的可持续性(Bellingham et al., 2000)。

植物在不同干扰条件下的繁殖对策可以反映植物对干扰的适应能力和生殖潜能,有助于理解植物对各种自然和人为干扰因素及其资源环境、生态过程和生态格局的适应意义。干扰发生频率和干扰强度影响植物繁殖对策的转换(James, 1984; Midgley, 1996; Kruger et al., 1997)。Bellingham等(2000)研究表明,萌生更新和种苗更新之间的平衡随着干扰发生频率的变化而变化,当干扰频繁发生时,更多的资源分配到萌生更新中,在中等强度干扰下,萌生更新对树木再生的贡献大于高强度干扰。在群落水平上,以低强度干扰下的萌生更新最具活力(不管干扰发生的频率如何)(Bellingham et al., 2000);当群落受到高频率干扰时,萌生更新能力和萌株的成活率会显著降低(陈小勇等, 1997),而种苗更新的机会将大大增加。高频率干扰使树木由有性繁殖向无性繁殖转换,长期生长在周期性洪水环境下的青冈(Cyclobalanopsis glauca)种群形成以萌生繁殖为主的更新方式,有性繁殖处于次要地位(陈小勇等, 1997);岷江上游的辽东栎(Quercus liaotungensis)在遭受仅40年的频繁干扰后,一些地段树木已由乔木生长型变成灌木生长型,森林更新方式由实生更新为主转变为萌生更新为主(包维楷等, 2000)。

萌生更新和实生更新是2种截然不同的更新策略,它们之间的协调主要体现在资源的分配和竞争上。与实生植株相比,大多数萌生植株具有多干(multi-stemmed)、矮小等形态特征,在没有干扰的情况下,单干型的树木具有较强的资源(如光照)竞争优势,而多干型、萌生型种类受到限制(Midgley, 1996);在干扰频繁发生条件下,萌生种类具有资源竞争优势,萌生种类将大量的资源储存于地下器官用于萌生更新(Bowen et al., 1993),分配于有性繁殖的资源有限。

1.2 在植被恢复演替中的作用

萌生更新在受干扰后森林植被尤其是次生植被的恢复和重建中具有重要作用(Kauffman, 1991; Basnet, 1993)。萌生更新是地中海硬叶栎林(Quercus ilex)受到干扰后植被恢复的主要途径(Espelta et al., 19951999),依靠萌生更新,地中海硬叶栎林在遭受火灾、过牧、薪柴和木炭生产等干扰后得以长期保存;萌生更新是西双版纳刀耕火种后植被恢复的主要方式(唐勇等, 2001)。云南哀牢山中山湿性常绿阔叶林中的木果柯(Lithocarpus xylocarpus)、硬壳柯(Lithocarpus hancei)、变色锥(Castanopsis rufescens)、南洋木荷(Schima noronhae)等优势树种具有较强的萌生能力,不仅对于伐木后森林的恢复具有极其重要的作用,也是其自然更新的一条重要途径(何永涛等,2000)。萌生更新对于森林灌丛管理尤为重要,干枯、干倒、火灾、砍伐等干扰发生后,森林通过萌生实现自然更新,改变森林动态。地中海型灌丛频繁遭受火灾,灌丛常常受到严重威胁,植被恢复主要依靠根系或残留树干(Keeley, 1977)。在所有萌生类型中,根桩萌生是受到干扰后植被恢复和重建的重要途径(Bellingham et al., 2000)。树木遭受火干扰后,即使地上大部分生物量被破坏,常常能萌生新的植株,萌生更新影响火干扰后森林的演替。萌生有助于减轻放牧对树木的影响,许多非洲草原灌丛在遭受大象影响后仍生长旺盛,丛生种对放牧的适应性比非丛生种强(Barnes, 1983)。

在低强度、高发生频率干扰环境下,森林动态平衡主要与个体死亡率和个体补充数量有关(Miura et al., 2001)。萌生更新对植物群落动态有重要影响,通过萌生更新可维持种群的数量,迅速恢复与完善森林植物群落结构及功能,是维持种群延续与稳定的一种重要方式,萌生能力强的群落常常具有较强的自我平衡调节能力和恢复力,且具有较强的稳定性。萌生更新可促进植物种群分布的缀块性和特有性动态(Fagerström et al., 1997; Bond et al., 2001),降低种群的周转率,减轻干扰对群落的影响,减少种群更新对种子的依赖性等(Bond et al., 2001)。萌生更新在一定程度上可影响群落的演替方向,萌生能力强的植物群落在遭受干扰后,由于萌生植株的“持续生态位”(persistence niche)效应,使得植被演替保持较好的连续性。萌生植物的“持续生态位”既可能延缓植被的演替速度(先锋种或演替前期种的持续时间),也可以加速演替速度(顶级种类的持续时间)。

1.3 对物种多样性的影响

萌生更新影响植物群落的物种组成和结构(Kammesheidt, 1998; Calvo et al., 2002; 喻理飞等, 2002; 朱教君, 2002)。Pausas等(1999)研究发现,萌生对群落的物种丰富度、种面积曲线等都具有重要影响。在干扰条件下,拥有较多萌生种类的植物群落能以萌生更新的方式,尽快恢复占领原有的生态位,使群落外其他种类难以有入侵定居的机会,因此,群落仍然保留了较多的原有的萌生能力强的物种(Grant et al., 1999),从而在一定程度上降低了群落内的物种多样性和物种周转率(Kruger et al., 2001)。相反,拥有较少萌生种类的植物群落,以及经过多次干扰而丧失萌生能力的种类组成的植物群落,由于缺乏“持续生态位”效应,留给群落外其他物种迁入的机会较多,因此干扰后植物群落结构和种类组成将发生根本性改变(Kruger et al., 2001; Ng et al., 2002)。Kammesheidt (1998)认为,萌生更新在森林植被恢复演替的初期起着重要作用,随着恢复演替的进行,萌生植株丰度呈下降趋势,萌生植株个体自然衰老程度增加,顶极群落物种逐步入侵,也就是说,萌生更新在植被恢复演替前期乃至中期物种组成和结构中具有重要意义,而在演替后期的作用逐渐减弱。同工酶技术运用研究表明,萌生植物的遗传多样性并不象早期预期的那么低,萌生植物群落仍然拥有丰富的遗传多样性(Ell strand et al., 1987; Hamrick et al., 1990),近十年来RAPDs、AFLPs、ISSRs等分子标记技术的应用也证实了萌生植物具有丰富的遗传多样性(McClellan et al., 1997)。

2 森林萌生更新的生理生态机理

植物的萌生是一个极其复杂的生理生态学过程。森林萌生更新生理生态机理的研究对于次生植被的恢复、保护和管理具有重要意义,有助于丰富森林更新理论的研究,扩展对植物功能型和功能特征的理解(Weiher et al., 1999; Bond et al., 2003)。森林萌生更新的基础是物种的萌生能力,它既受生境、干扰、资源水平等外在因素的影响,又受内部营养水平和激素合成等控制,是两者共同作用的结果。根据国内外有关森林植物萌生更新研究文献,将森林萌生更新形成的生理生态机理归纳为6种假说:生物地理假说、生境假说、营养假说、干扰假说、资源分配假说和激素调控假说,这些假说从各自的角度均能较好地解释植物的萌生更新机理,但是它们又有一定的局限性。

2.1 生物地理假说

生物地理假说认为,萌生更新与生物地理群落有关,不同物种萌生更新能力不同(Zimmerman et al., 1994; Peterson et al., 1997; Paciorek et al., 2000)。由于Quercus mongolica var. grosseserrata具有较强的萌生恢复能力,在遭受火干扰后成为群落的优势种。温带森林植被中萌生种类所占的比例(35.9%)较热带森林中萌生种类所占比例(51.5%)要低,且在较为潮湿的森林植被中萌生种类增加,温带森林植被中萌生种类较少的可能原因是由于温带森林中针叶树种比例较大,大多数针叶树种不具备萌生能力或萌生能力较低;热带森林中不仅拥有较高的萌生种类比例,而且萌生干的发生率(平均为85.2%)也较高(Everham et al., 1996)。对墨西哥东南部热带森林的人工砍伐试验表明,17个热带树种均为萌生种,但萌生能力不同(Negreros et al., 2000)。Vesk等(2004a)通过对不同类型植被的萌生综合分析表明,植被类型对植物萌生能力的影响较小。成熟森林中包括较多比例的持续萌生更新树种,对其他生物地理群落的萌生更新研究较少。不同生活史阶段,森林植物萌生响应不同,一些物种从不萌生,而一些种萌生能力随着成年阶段个体大小的增加而增加,另外有的种类在幼树阶段萌生更新现象十分普遍,但进入成年阶段却不能萌生(Everham et al., 1996; Hodgkinson, 1998; Bellingham et al., 2000)。

2.2 生境假说

生境假说认为,树木生长环境不同,萌生更新能力不同。生长在林窗下和林窗附近的树木比树冠下的树木具有更多的萌生植株(Miura et al., 2003Daisuke et al., 2003)。坡位和庇荫条件是影响Quercus ilex萌生能力和萌株生长的2个关键因子,其中坡位比庇荫条件的影响更显著,坡位影响萌株的高生长,但对直径生长影响较小,庇荫对萌株直径生长有显著影响,萌株树冠生长既受坡位影响,又受庇荫条件的影响(Gracia et al., 2004)。在澳大利亚,生长在湿润、土壤营养条件较好立地条件下的Nothofagus cunninghamii主要依靠种子更新,而在干旱、瘠薄的立地条件下以萌生更新为主(Read et al., 1996),在南非森林植物中也发现同样的现象(Kruger et al., 1997)。还有研究显示,干旱、高温、种子被严重捕食和过度放牧等恶劣环境对植物萌生更新具有选择优势,而这些环境条件不适合种子的萌发和幼苗的定居(Bellingham et al., 2000; Bond et al., 2001; Midgley, 1996)。

2.3 营养假说

营养假说认为,树木萌生能力和萌株生长与母树根系和土壤营养储存相关。Paulo等(2002)对7年生尾叶桉(Eucalyptus urophylla)砍伐后萌生植株营养与母树根系和土壤营养的动态关系研究表明,土壤、粗根(ϕ>3mm)和主根是萌生植株生长初期的主要营养来源。砍伐60天后,树木萌生及生长所需要的营养因素除K、Mg外均来源于土壤,K和Mg主要来源于母树根系储存;砍伐第60~120天,母树根系对萌株生长所需的N、P、Ca贡献较大;砍伐后第330天萌株生长所需N元素的9.2%、K元素的23.9%、Mg元素的12.6%由母树根系供应,而几乎所有的P和Ca元素均由土壤供应。也有研究表明,生长在庇荫环境和较差的土壤条件下的植物反而具有较强的萌生更新能力(Koop, 1987; Verwijst, 1988)。

2.4 干扰假说

干扰假说认为,火、风、滑坡、雪崩、动物、砍伐等自然和人为干扰是驱动森林萌生更新的主要因素。植株萌生能力与干扰类型、干扰频率、强度、干扰季节、受干扰树体的大小等有关。干扰类型中,对单株萌生能力影响最大的是砍伐,其次是火烧,最后是深耕,深耕会破坏植株根系(Roundy et al., 1988)。干旱森林砍伐后许多树种具有萌生能力(de Figueirôa et al., 2006)。砍伐后的萌生率高于火烧,砍伐留桩的高度和直径影响萌生率(Hodgkinson, 1998; 高建等, 1995; 李景文等, 2005),萌生率与萌株数量随树桩直径的增加而减少,随树桩高度的增加而增加(Khan et al., 1986),以灌木基部留高30~50 cm的萌生率为较高(Hodgkinson, 1998)。不同砍伐时期萌株的高度生长没有显著差异,以5—7月砍伐树桩萌株数量为最少(Johansson, 1992)。砍伐干扰后树木萌生较火干扰快,砍伐干扰后残余植物体休眠芽一般在2个月内就可萌发,而火干扰后植株在很长一段时间内仍有萌生能力(Gracia et al., 2004)。对南美几种森林植被萌生更新的比较研究也表明,以遭受砍伐和火干扰的森林植被的萌生更新水平为最高(Kammesheidt, 1999)。Vesk等(2004b)将植物对火灾干扰的响应分成2类,即非萌生种(non-sprouters)和萌生种(sprouters),大多数植物介于非萌生种和萌生种之间,非萌生种很少。萌生更新和实生更新之间的平衡随着干扰发生频率的变化而变化,当干扰频繁发生时,更多的资源分配到萌生更新中(Bellingham et al., 2000)。火灾是影响地中海硬叶栎林实生更新和萌生更新之间选择的主要因素,高强度和频繁发生的火灾有利于萌生更新,而在轻度火干扰条件下以种苗更新为主(Espelta et al., 19951999; Higgins et al., 2000)。

2.5 资源分配假说

资源分配假说认为,萌生更新能力取决于母树地上器官和地下器官的资源储存(Iwasa et al., 1997),地上部分损失后,树桩和根系是树木萌生更新碳源的主要来源,根系的资源储存量对于树木萌生再生具有重要的意义(FitzGerald et al., 1983; Kays et al., 1991; Bowen et al., 1993)。Malanson等(1988)发现Quercus coccifera灌丛因遭受火干扰而损失地上部分生物量后,9年生灌丛萌生能力比3年生灌丛旺盛,可能是由于它们地下营养储存的差异。萌生更新需要消耗资源(Bond et al., 2001),有研究证实,在植株茎干砍伐后的萌生过程中,有植株储存的碳水化合物的消耗(Danckwerts et al., 1989; Kays et al., 1991; McPherson et al., 1998; von Fircks et al., 1998),栎树幼树生长发育良好的主根为萌生更新提供了碳源(Kruger et al., 1993; Sakai et al., 1998)。全球变化背景下,CO2浓度的升高可增强植物的萌枝能力(Hoffmann et al., 2000)。

在几乎损失了所有地上部分生物量后,植株的萌生更新需要有幸存芽或其他分生组织,以及能够支撑新萌生植株第一片叶展开所需要的碳水化合物和营养储存作保障(Pate et al., 1990; Canadell et al., 1998; Bond et al., 2001; Vesk et al., 2004c)。基于植株个体的萌芽更新模型主要关注碳水化合物的储存(Iwasa et al., 1997; de Jong et al., 2000),或牲畜干扰后萌芽库状况(van der Meijden, 1990; Vail, 1992; Tuomi et al., 1994; Nilsson et al., 1996)。

Olano等(2006)报道,火干扰0.5~40年后,5种萌生灌丛植物地下储存器官非结构性碳水化合物的含量存在明显的种间差异,拥有特殊储存器官(如根状茎)的Palafoxia feayiSmilax auriculata更能有效地储存碳源,并具有较高的非结构性碳水化合物(Nonstructural carbohydrate, NSC)浓度,除Licania micbauxii外,其余4种根系的NSC含量与火干扰后时间表现出明显的相关关系,其中Smilax auriculataQuercus geminata呈正相关,Palafoxia feayiVaccinium myrsinites呈负相关,非可溶性糖(Nonsoluble sugars, NSS)浓度随着火干扰后灌丛个体多度的增加而增加,证实了萌生树种火干扰后个体丰度与地下器官NSC浓度相关。干扰后NSC的消耗可能导致萌生植株的死亡,降低再萌生的能力(McPherson et al., 1998; Cruz et al., 2003)。

火干扰后萌生能力较强的植物,常常拥有庞大的根系,并储存有大量的碳源和营养元素用于萌生更新(Pate et al., 1990; 1991; Hansen et al., 1991; Bowen et al., 1993)。植物的萌生能力与地下器官淀粉的储存水平有关(Pate et al., 1990; 1991; Bowen et al., 1993; Zasada et al., 1994)。Pate等(1990)对澳大利亚草原灌木和草本植物的研究表明,萌生种类植株根的淀粉含量比非萌生种类植株平均高4倍,根比干高4~5倍,而生物量低一半。澳大利亚的尖苞树科(Epacridaceae)灌木(Bell, 1996)和南非的杜鹃花科(Ericaceae)灌木(Bell et al., 1999)亦有了类似的研究结果。在澳大利亚西南部火烧迹地恢复植被中,帚灯草科(Restionaceae)中萌生种比非萌生种具有较高的碳水化合物浓度(Pate et al., 1991)。随着树木砍伐后时间的延长,柔毛桦(Betula pubescens)有根系碳水化合物浓度降低,且降低速度高于垂枝桦(Betula pendula),这与柔毛桦的萌生能力比垂枝桦强是一致的,根桩中碳水化合物浓度较低(Luostarinen et al., 2005)。

非结构性碳水化合物是参与植物生命过程的重要物质,植株体内非结构性碳水化合物的代谢在很大程度上影响着植株的生长发育及对环境的适应(Koch, 1996; Van den Ende et al., 1999; Loewe et al., 2000; 潘庆民等, 2002)。根据树木NSC的季节变化(Simon et al., 2003)可以推测,不同干扰季节植物萌生能力不同,干扰时间发生在春季,植株一般有较强的萌生能力;发生在秋季,萌生能力较弱;当干扰发生在冬季时,萌发将在第2个生长季节,即次年的3—4月份开始。

与资源分配假说相对立的还有资源不利用假说(resource disuse hypothesis)和构筑限制假说(architectural constrain hypothesis)。资源不利用假说认为,树木储存的资源在本质上并不用于萌生更新,而是用于萌株在与相邻其他树木竞争的生长中。该假说适用于生长在弱竞争环境中的树木,如不稳定的陡坡地,它们不需要储存资源用于萌生更新(Sakai et al., 1997)。据Sakai等(19971998)报道,生长在土层薄、多岩石立地条件下的Euptelea polyandra,不但根生物量所占比重较小,而且根系资源储存也较少,但在遭受干扰后树木的萌生能力却较强,主要是由于该树木在遭受飓风干扰后,树木能够利用幸存的地上部分光合器官恢复资源,而不需要储存资源用于萌生,这在树木地上生物量仅遭受部分干扰情况下较为普遍。构筑限制假说认为,生长在土层薄、不稳定立地条件下的树木,难以形成庞大的根系和有效储存资源,事实上,不同幼树根的构筑不同,Euptelea polyandra主根不发育,而侧根发育,这与其生长地土层薄、不稳定且岩石多有关,发育良好的侧根有利于树木固定和从多岩石土壤中吸收营养,因此这种根系不适合于资源的储存(Sakai et al., 1997)。

2.6 激素调控假说

激素调控假说认为,树木的萌生更新能力受树木体内激素水平的调控。吲哚乙酸(IAA)和细胞分裂素在树木根萌生中起着重要的作用(Cline, 1991),两者的比率调控植物器官再生,低比率促进植物愈伤组织形成和萌生形成(Sachs, 1991)。植株受损后细胞分裂素的聚集和IAA的减少被认为是萌芽形成和萌生的主要原因。IAA的极性运输在抑制根萌动中起着重要作用。砍伐树桩上施用IAA可抑制根萌动和干萌生(Wan et al., 2006)。高浓度的细胞分裂素抑制根形成和侧根延长(Hopkins, 1999), 但促进茎干萌芽和枝的形成(Schmuelling, 2002)。玫瑰属植物基部树皮组织、茎节含有树干基芽萌生的抑制剂,基部树皮组织发现有较高含量的细胞分裂素,植物体内细胞分裂素和抑制化合物之间的平衡调节着基芽生长和植物再生。根中硝酸盐的积累可能是根萌生的一种信号物质,硝酸盐促进细胞分裂素的形成(Scheible et al., 1997; Forde, 2002; Schmuelling, 2002)。树木地上部分损失后,树桩和根中信号物质(可能是细胞分裂素或无机氮化合物,或两者兼有)的积累诱导了白杨根萌生和干基萌生(Eliasson, 1971; Wan et al., 2006)。根是细胞分裂素合成的主要器官,细胞分裂素通过木质部运输到植物地上器官(Van et al., 1979),植物地上部分损失后,由根运输到树桩的细胞分裂素增多(Mader et al., 2003)。

3 研究展望 3.1 森林萌生更新的群落生态学研究

主要开展不同的生态系统和不同森林植被类型萌生植物的分布特征、不同时空尺度下萌生植物的丰度变化、萌生更新对群落多样性的影响、萌生植物的“持续生态位”效应对群落内物种多样性的影响、萌生更新和种子更新之间平衡关系的调节、萌生更新群落的低周转率是否降低了物种丰度、萌生是否影响植株的竞争力并减缓演替的速率、萌生侵入种和非萌生侵入种与群落个体增加之间的关系、萌生更新和群落稳定性的关系、萌生行为变异的进化结果等研究,以及萌生更新的种群数量、结构、动态、生长格局和存活状况等。Bond等(2001)认为,应关注顶极植物群落的萌生现象,以评估萌生更新对植物群落稳定性的贡献。

3.2 森林萌生更新的生理生态适应性研究

作为一种主要的森林更新方式,对萌生更新形成的生理生态机制了解还是很少,干扰是驱动种群、群落和生态系统萌生更新演变的动力,各种干扰类型对萌生的作用机理目前尚不明确,开展植物萌生对干扰的响应与适应机制研究,包括干扰胁迫下萌生更新的生理生态、生殖生态、遗传生态以及与分子水平密切相关的研究,萌株地下器官、萌株对基株的影响、萌株病虫害的防治及萌株间的化感作用研究,以及萌生植物生态系统中分子水平的信息传递、遗传变异、分化、适应等研究。应用RAPDs、AFLPs、ISSRs等分子标记技术开展萌生植物的遗传多样性研究。开展萌生植株对不同土壤、气候条件的生理生态适应性研究,及其对全球变化的生理生态响应。

3.3 在森林植被恢复和生态重建中的应用

中国次生植被分布广泛,萌生更新是其重要的更新方式(喻理飞等, 2002; 朱教君, 2002)。如何将森林萌生更新理论与次生植被的恢复和生态重建相结合,是未来需要加强研究的领域。研究干扰条件下植被的萌生过程和种群发展,可为植被恢复和生态重建以及生物多样性的保护提供理论依据。萌生植被为检验萌生更新理论提供了良好的试验材料和方法,应加强萌生更新理论和生产实践相结合的研究。

参考文献(References)
包维楷, 陈庆恒, 刘照光. 2000. 退化植物群落结构及其特种组成在人为干扰梯度上的响应. 云南植物研究, 22(3): 307-316. DOI:10.3969/j.issn.2095-0845.2000.03.012
陈小勇, 宋永昌. 1997. 洪水干扰对青冈群更新的影响. 热带亚热带植物学报, 5(1): 53-58.
董金伟, 杜华兵, 刘呈苓, 等. 2001. 伐桩不同处理对山地刺槐无性更新影响的研究. 山东林业科技, 4: 10-11.
方升佐, 徐锡增, 吕士行, 等. 2000. 杨树萌芽更新及持续生产力. 南京林业大学学报, 34(4): 43-48. DOI:10.3969/j.issn.1000-2006.2000.04.011
高建, 刘令峰, 叶镜中. 1995. 伐桩粗度和高度对杉木萌芽更新的影响. 安徽农业大学学报, 22(2): 145-149.
何永涛, 曹敏, 唐勇, 等. 2000. 云南省哀劳山湿性常绿阔叶林萌生现象的初步研究. 武汉植物学研究, 18(6): 523-527. DOI:10.3969/j.issn.2095-0837.2000.06.015
荆涛, 马万里, Joni K, 等. 2002. 水曲柳萌芽更新的研究. 北京林业大学学报, 24(4): 12-15.
李景文, 聂绍荃, 安滨河. 2005. 东北东部林区次生林主要阔叶树种的萌芽更新规律. 林业科学, 41(6): 72-77. DOI:10.3321/j.issn:1001-7488.2005.06.011
林星华. 2001. 巨尾桉二代萌芽更新林分密度调控技术研究. 林业科学研究, 14(3): 283-287. DOI:10.3321/j.issn:1001-1498.2001.03.008
卢景龙, 卫金. 2001. 杨树人工林萌芽更新初报. 山西师范大学学报:自然科学版, 15(1): 57-60.
马祥庆, 刘爱琴. 2000. 杉木免耕萌芽更新生态效果研究. 中南林学院学报, 20(1): 14-18. DOI:10.3969/j.issn.1673-923X.2000.01.003
潘庆民, 韩兴国, 白云飞, 等. 2002. 植物非结构性贮藏碳水化合物的生理生态学研究进展. 植物学通报, 19: 30-38. DOI:10.3969/j.issn.1674-3466.2002.01.004
唐勇, 冯志立, 曹敏. 2001. 西双版纳刀耕火种轮歇地的萌生植物. 东北林业大学学报, 29(4): 64-66. DOI:10.3969/j.issn.1000-5382.2001.04.019
闫恩荣, 王希华, 施家月, 等. 2005. 木本植物萌枝生态学研究进展. 应用生态学报, 16(12): 2459-2464. DOI:10.3321/j.issn:1001-9332.2005.12.046
喻理飞, 朱守谦, 叶镜中, 等. 2002. 退化喀斯特森林自然恢复过程中群落动态研究. 林业科学, 38(1): 2-7.
于明坚. 1999. 青冈常绿阔叶林群落动态分析. 林业科学, 35(6): 42-51. DOI:10.3321/j.issn:1001-7488.1999.06.006
朱教君. 2002. 次生林经营基础研究进展. 应用生态学报, 13(12): 1689-1694. DOI:10.3321/j.issn:1001-9332.2002.12.040
Barnes R F W. 1983. Effects of elephant browsing on woodlands in a Tanzanian national park, measurements, models and management. Journal of Applied Ecology, 20: 521-540. DOI:10.2307/2403524
Basnet K. 1993. Recovery of a tropical rain forest after hurricane damage. Vegetatio, 109: 1-4. DOI:10.1007/BF00149540
Bell T L. 1996. Relationships between fire response, morphology, root anatomy and starch distribution in southwest Australian Epacridaceae. Annals of Botany, 77: 357-364. DOI:10.1006/anbo.1996.0043
Bell T L, Ojeda F. 1999. Underground starch storage in Erica species of the Cape floristic region differences between seeders and resprouters. New Phytologist, 144: 143-152. DOI:10.1046/j.1469-8137.1999.00489.x
Bellingham P J, Sparrow A D. 2000. Resprouting as a life history strategy in woody plant communities. Oikos, 89: 409-416. DOI:10.1034/j.1600-0706.2000.890224.x
Bellingham P J, Tanner E V J., Healey J R. 1994. Sprouting of trees in Jamaican mountain forests, after a hurricane. Journal of Ecology, 82: 747-758. DOI:10.2307/2261440
Bond W J, Midgley J J. 2001. Ecology of sprouting in woody plants: The persistence niche. Trends in Ecology & Evolution, 16: 45-51.
Bond W J, Midgley J J. 2003. The evolutionary ecology of sprouting. International Journal of Plant Sciences, 164: S103-S114. DOI:10.1086/374191
Bowen B J, Pate J S. 1993. The significance of root starch in post-fire shoot recovery of the resprouter Stirlingia latifolia R. Br. (Proteaceae). Annual Journal of Botany, 72: 7-16. DOI:10.1006/anbo.1993.1075
Calvo L, Tarrega R, Luis E. 2002. Secondary succession after perturbations in a shrubland community. Acta Oecologica, 23: 393-404. DOI:10.1016/S1146-609X(02)01164-5
Canadell J, López-Soria L. 1998. Lignotuber reserves support regrowth following clipping of two Mediterranean shrubs. Functional Ecology, 12: 31-38. DOI:10.1046/j.1365-2435.1998.00154.x
Cline M G. 1991. Apical dominance. Botanic Review, 57: 318-358. DOI:10.1007/BF02858771
Cruz A, Pérez B, Moreno J M. 2003. Resprouting of the Mediterranean-type shrub Erica australis with modified lignotuber content. Journal of Ecology, 91: 348-356. DOI:10.1046/j.1365-2745.2003.00770.x
Daisuke K, Akiko S, Kiyoshi M. 2003. Resprouting ability of Quercus crispula seedling depends on vegetation cover of their microhabits. Journal of Plant Research, 116: 207-216. DOI:10.1007/s10265-003-0089-3
Danckwerts J E, Gordon A J. 1989. Long-term partitioning, storage and remobilization of 14C assimilated by Trifolium repens (cv. Blanca). Annals of Botany, 64: 533-544. DOI:10.1093/oxfordjournals.aob.a087875
de Figueirôa J M, Pareyn F G C, de Lima A E, et al. 2006. Effects of cutting regimes in the dry and wet season on survival and sprouting of woody species from the semi-arid caatinga of northeast Brazil. Forest Ecology and Management, 229: 294-303. DOI:10.1016/j.foreco.2006.04.008
de Jong T J, van der Meijden E. 2000. On the correlation between allocation to defence and regrowth in plants. Oikos, 88: 503-508. DOI:10.1034/j.1600-0706.2000.880305.x
Eliasson L. 1971. Growth regulators in Populus tremula Ⅳ: Apical dominance and suckering in young plants. Physiology of Plant, 25: 263-267. DOI:10.1111/j.1399-3054.1971.tb01440.x
Ell strand N C, Roose M L. 1987. Patterns of genotypic diversity in clonal plants species. American Journal of Botany, 74: 123-131. DOI:10.1002/j.1537-2197.1987.tb08586.x
Espelta J M, Riba M, Retana J. 1995. Patterns of seedling recruitment in west Mediterranean Quercus ilex forests influenced by canopy development. Journal of Vegetation Science, 6: 465-472. DOI:10.2307/3236344
Espelta J M, Sabate S, Retana J. 1999. Resprouting dynamics//Roda F, Retana J, Gracia C A, et al. Ecology of Mediterranean Evergreen Oak Forests. Berlin: Springer, 61-73
Everham E M, Brokaw N V L. 1996. Forest damage and recovery from catastrophic wind. Botanic Review, 62: 113-185. DOI:10.1007/BF02857920
Fagerström T, Westoby M. 1997. Population dynamics in sessile organisms, some general results from three seemingly different theory-lineages. Oikos, 80: 588-594. DOI:10.2307/3546634
FitzGerald R D, Hoddinott J. 1983. The utilization of carbohydrates in aspen roots following partial or complete top removal. Canadian Journal of Forest Research, 13: 685-689. DOI:10.1139/x83-098
Forde B G. 2002. Local and long-range signaling pathways regulating plant responses to nitrate. Annual Review of Plant Biology, 53: 203-224. DOI:10.1146/annurev.arplant.53.100301.135256
Gracia M, Retanab J. 2004. Effect of site quality and shading on sprouting patterns of holm oak coppices. Forest Ecology and Management, 188: 39-49. DOI:10.1016/j.foreco.2003.07.023
Grant C D, Loneragan W A. 1999. The effects of burning on the understorey composition of 11-13 year-old rehabilitated bauxite mines in Western Australia. Plant Ecology, 145: 291-305. DOI:10.1023/A:1009821128075
Grubb P J. 1977. The maintenance of species richness in communities, the importance of the regeneration niche. Biological Reviews, 52: 107-145.
Hamrick J L, Golt M J W. 1990. Allozyme diversity in plants species//Brown A H, Clegg M J, Kahler A L. Plant population genetics, breeding and genetic resources. Sunderland: Sinauser Associate, 43-63
Hansen A, Pate J S, Hansen A P. 1991. Growth and reproductive performance of a seeder and a resprouter species of Bossiaea as a function of plant age after fire. Annals of Botany, 67: 497-509. DOI:10.1093/oxfordjournals.aob.a088190
Higgins S I. 2000. Predicting extinction risks for plants, environmental stochasticity can save declining populations. Trends in Ecology & Evolution, 15: 517-520.
Hodgkinson K C. 1998. Sprouting success of shrubs after fire, height-dependent relationships for different strategies. Oecologia, 115: 64-72. DOI:10.1007/s004420050492
Hoffmann W A, Bazzaz F A, Chatterton NJ. 2000. Elevated CO2 enhances respouting of a tropical savanna tree. Oecologia, 123(3): 312-317. DOI:10.1007/s004420051017
Hopkins W G. 1999. Introduction to plant physiology. New York: John Wiley & Sons, 325-328.
Iwasa Y, Kubo T. 1997. Optimal size of storage for recovery after unpredictable disturbances. Evolutionary Ecology, 11: 41-65. DOI:10.1023/A:1018483429029
James S. 1984. Lignothbers and burls their structure, function and ecological significance in Mediterranean ecosystems. Botanic Review, 50: 225-266. DOI:10.1007/BF02862633
Johansson T. 1992. Sprouting of 10-to 50-year-old Betula pubescens in relation to felling time. Forest Ecology and Management, 53: 263-281. DOI:10.1016/0378-1127(92)90046-C
Kammesheidt L. 1998. The role of tree sprouts in the restoration of stand structure and species diversity in tropical moist forest after slash-and-burn agriculture in Eastern Paraguay. Plant Ecology, 139: 155-165. DOI:10.1023/A:1009763402998
Kammeshedt L. 1999. Forest recovery by root suekers and above ground sprouts after slash-and-burn agriculture, fire and logging in Paraguay and Venezuela. Journal of Tropical Ecology, 15: 143-157. DOI:10.1017/S0266467499000723
Kauffman J B. 1991. Survival by sprouting following fire in tropical forests of the eastern Amazon. Biotropica, 23: 219-224. DOI:10.2307/2388198
Kays J S, Canham C D. 1991. Effects of time and frequency of cutting on hardwood root reserves and sprout growth. Forest Science, 37: 524-539.
Khan M L, Tripathi R S. 1986. Tree regeneration in a disturbed sub-tropical wet hill forest of north-east India: Effect of stump diameter and height on sprouting of Four tree species. Forest Ecology and Management, 17: 199-209. DOI:10.1016/0378-1127(86)90112-X
Keeley J E. 1977. Seed production, seed populations in soil, and seedling production after fire for two congeneric pairs of sprouting and nonsprouting chaparral shrubs. Ecology, 58: 820-829. DOI:10.2307/1936217
Koch K E. 1996. Carbohydrate-modulated gene expression in plants. Annual Review of Plant Physiology and Plant Molecular Biology, 47: 509-540. DOI:10.1146/annurev.arplant.47.1.509
Koop H. 1987. Vegetative reproduction of trees in some European natural forests. Vegetation, 72: 103-110.
Kowarik I. 1995. Clonal growth in Ailanthus altissima on a natural site in West Virginia. Journal of Vegetation Science, 6: 853-856. DOI:10.2307/3236399
Kruger E L, Reich P B. 1993. Coppicing affects growth, root shoot relations and ecophysiology of potted Quercus rubra seedlings. Physiology of Plant, 89: 751-760. DOI:10.1111/j.1399-3054.1993.tb05281.x
Kruger L M, Midgley J J, Cowling R M. 1997. Resprouters vs reseeders in South African forest trees; a model based on forest canopy height. Functional Ecology, 11: 101-105. DOI:10.1046/j.1365-2435.1997.00064.x
Kruger L M, Midgley J J. 2001. The influence of resprouting forest canopy species on richness in Southern Cape forests, South Africa. Global Ecology & Biogeography, 10: 567-572.
Loewe A, Einig W, Shi L, et al. 2000. Mycorrhiza formation and elevated CO2 both increase the capacity for sucrose synthesis in source leaves of spruce and aspen. New Phytologist, 145: 565-574. DOI:10.1046/j.1469-8137.2000.00598.x
Luostarinen K, Kauppi A. 2005. Effects of coppicing on the root and stump carbohydrate dynamics in birches. New Forests, 29: 289-303. DOI:10.1007/s11056-005-5653-3
Mader J C, Turnbull C G N, Emery R J N. 2003. Transport and metabolism of xylem cytokinins during lateral bud release in decapitated chickpea (Cicer arietinum) seedlings. Physiology of Plant, 117: 118-129. DOI:10.1034/j.1399-3054.2003.1170115.x
Malanson G P, abaud L. 1988. Vigour of post-fire resprouting by Quercus coccifera L. Journal of Ecology, 76: 351-365. DOI:10.2307/2260598
McClellan A J, Prati D, Kaltz O, et al. 1997. Structure and analysis of phenotypic and genetic variation in clonal plants//de Kroon H, van Groenendael J. The ecology and evolution of clonal plants. Leiden: Netverlands, 185-210
McPherson K, Williams K. 1998. The role of carbohydrate reserves in the growth, resilience, and persistence of cabbage palm seedlings (Sabal palmetto). Oecologia, 117: 460-468. DOI:10.1007/s004420050681
Midgley J J. 1996. Why the world's vegetation is not totally dominated by resprouting plants, because resprouters are shorter than reseeders. Ecography, 19: 92-95. DOI:10.1111/j.1600-0587.1996.tb00159.x
Miura M, Manabe T, Nishimura N, et al. 2001. Forest canopy and community dynamics in a temperate old-growth evergreen broad-leaved forest, south-western Japan, a 7-year study of a 4-ha plot. Journal of Ecology, 89: 841-849. DOI:10.1046/j.0022-0477.2001.00603.x
Miura M, Yamamoto S. 2003. Structure and dynamics of a Castanopsis cuspidate var. sieboldii population in an old-growth, evergreen, broad-leaved forest, The importance of sprout regeneration. Ecological Research, 18: 115-129.
Ng S C, Corlett R. 2002. The ecology of six Rhododendron species (Ericaceae) with contrasting local abundance and distribution patterns in Hong Kong, China. Plant Ecology, 164: 225-233.
Negrelle R R B. 1995. Sprouting after uprooting of canopy trees in the Atlantic rain forest of Brazil. Biotropica, 27(4): 448-454. DOI:10.2307/2388957
Negreros C P, Hall R B. 2000. Sprouting capability of 17 tropical tree species after overstory removal in Quintana Roo, Mexico. Forest Ecology and Management, 126: 399-403. DOI:10.1016/S0378-1127(99)00109-7
Nilsson P, Tuomi J, Astrom M. 1996. Bud dormancy as a bet-hedging strategy. American Naturalist, 147: 269-281. DOI:10.1086/285849
Ohkubo T, Kaji M, Hayama T. 1988. Structure of primary Japanese beech (Fagus japonica Maxim.) forests in the Chichibu mountains, central Japan, with special reference to regeneration processes. Ecological Research, 3: 101-116.
Olano J M, Menges E S, Martinez E. 2006. Carbohydrate storage in fine respouting Florida scrub plants across a fire chronosequence. New Phytologist, 170: 99-106. DOI:10.1111/j.1469-8137.2005.01634.x
Paciorek C J, Condit R, Hubbell S P, et al. 2000. The demographics of resprouting in tree and shrub species of a moist tropical forest. Journal of Ecology, 88: 765-777. DOI:10.1046/j.1365-2745.2000.00494.x
Pate J S, Froend R H, Bowen B J, et al. 1990. Seedling growth and storage characteristics of seeder and resprouter species of Mediterranean-type ecosystems of S.W. Australia. Annals of Botany, 65: 585-601. DOI:10.1093/oxfordjournals.aob.a087976
Pate J S, Meney K A, Dixon K W. 1991. Contrasting growth and morphological characteristics of fire-sensitive (obligate seeder) and fire-resistant (resprouter) species of Restionaceae (S. Hemisphere Restiads) from south-western Western Australia. Australian Journal of Botany, 39: 505-525.
Paulo C T, Roberto F N, Nairam F B. 2002. Eucalyptus urophylla root growth, stem sprouting and nutrient supply from the roots and soil. Forest Ecology and Management, 160: 263-271. DOI:10.1016/S0378-1127(01)00469-8
Pausas J G, Carbo E, Caturla R N. 1999. Postfire regeneration patterns in the eastern Iberian Peninsula. Acta Oecologica, 20(5): 499-508. DOI:10.1016/S1146-609X(00)86617-5
Peterson C J, Rebertus A J. 1997. Tornado damage and initial recovery in three adjacent lowland temperate forests in Missouri. Journal of Vegetation Science, 8: 559-564. DOI:10.2307/3237207
Pigott C D. 1993. Are the distributions of species determined by failure to set seed?//Marshall C, Grace J. Fruit and Seed Production. New York: Cambridge University Press, 203-216
Putz F E, Brokaw N V L. 1989. Sprouting of broken trees on Barro Colorado Island, Panama. Ecology, 70(2): 508-512. DOI:10.2307/1937555
Read J, Brown M J. 1996. Ecology of Australian Nothofagus forests//Veblen T T, Hill R S, Read J. The ecology and biogeography of Nothofagus Forests. Connecticut: Yale Univ Press: 131-181
Rijks M H, Malta E J, Zagt R J. 1998. Regeneration through sprout formation in Chlorocardium rodiei (Lauraceae) in Guyana. Journal of Tropical Ecology, 14: 463-475. DOI:10.1017/S0266467498000340
Roundy B A, Jordan G L. 1988. Vegetation changes in relation to livestock exclusion and root plowing in southeastern Arizona (USA). The Southwestern Naturalist, 33: 425-436. DOI:10.2307/3672210
Sachs T. 1991. Pattern formation in plant tissues. New York: Cambridge University Press, 234.
Sakai A, Sakai S. 1998. A Test for the resource remobilization hypothesis, tree sprouting using carbohydrates from above-ground parts. Annals of Botany, 82: 213-216. DOI:10.1006/anbo.1998.0672
Sakai A, Sakai S, Akiyam F. 1997. Do sprouting tree species on erotion-prone sites carry reserves of resources?. Annals of Botany, 79: 625-630. DOI:10.1006/anbo.1996.0389
Scheible W R, Lauerer E D, Schulze M C, et al. 1997. Accumulation of nitrate in the shoot acts as a signal to regulate shoot-root allocation in tobacco. Plant Journal, 11: 671-691. DOI:10.1046/j.1365-313X.1997.11040671.x
Schmuelling T. 2002. New insights into the functions of cytokinins in plant development. Journal of Plant Growth Regulation, 21: 40-49. DOI:10.1007/s003440010046
Simon M L, Victor J L. 2003. Seasonal changes in carbohydrate reserves in matyre northern Populus tremuloides clones. Trees, 17: 471-476. DOI:10.1007/s00468-003-0263-1
Tuomi J, Nilsson P, Astrom M. 1994. Plant compensatory responses-bud dormancy as an adaptation to herbivory. Ecology, 75: 1429-1436. DOI:10.2307/1937466
van der Meijden E. 1990. Herbivory as a trigger for growth. Functional Ecology, 4: 597-598. DOI:10.2307/2389328
Van den Ende W, Roover J D, Laere A V. 1999. Effect of nitrogen concentration on fructan metabolizing enzymes in young chicory plants (Cichorium intybus). Physiology of Plant, 105: 2-8. DOI:10.1034/j.1399-3054.1999.105102.x
Van S J, Davey J E. 1979. The synthesis, transport and metabolism of endogenous cytokinins. Plant Cell and Environment, 2: 93-106. DOI:10.1111/j.1365-3040.1979.tb00780.x
Vail S G. 1992. Selection for overcompensatory responses to herbivory, a mechanism for the evolution of plant-herbivore mutualism. American Naturalist, 139: 1-8. DOI:10.1086/285309
Verwijst T. 1988. Environmental correlates of multiple-stem formation in Betula pubescens ssp. tortuosa. Vegetation, 76: 29-36.
Vesk P A, Westoby M. 2004a. Sprouting ability across diverse disturbances and vegetation types worldwide. Journal of Ecology, 92: 310-320. DOI:10.1111/j.0022-0477.2004.00871.x
Vesk P A, Warton D I, Westoby M. 2004b. Sprouting by semi-arid plants, testing a dichotomy and predictive traits. Oikos, 107: 72-89. DOI:10.1111/j.0030-1299.2004.13122.x
Vesk P A, Westoby M. 2004c. Funding the bud bank, a review of the costs of buds. Oikos, 106: 200-208. DOI:10.1111/j.0030-1299.2004.13204.x
von Fircks Y, Sennerby F L. 1998. Seasonal fluctuations of starch in root and stem tissues of coppiced Salix viminalis plants grown under two nitrogen regimes. Tree Physiology, 18: 243-249. DOI:10.1093/treephys/18.4.243
Wan X C, Landhausser S M, Lieffers V J, et al. 2006. Signals controlling root suckering and adventitious shoot formation in aspen (Populus tremuloides). Tree Physiology, 26: 681-687. DOI:10.1093/treephys/26.5.681
Weiher E, van der Werf A, Thompson K, et al. 1999. Challenging Theophrastus, a common core list of plant traits for functional ecology. Journal of Vegetation Science, 10: 609-620. DOI:10.2307/3237076
Wells P V. 1969. The relation between mode of reproduction and extent of speciation in woody genera of the California chaparral. Evolution, 23: 264-267. DOI:10.1111/j.1558-5646.1969.tb03510.x
Yamamoto S, Nishimura N, Matsui K. 1995. Natural disturbance and tree species coexistence in an old-growth beech dwarf bamboo forest, southwestern Japan. Journal of Vegetation Science, 6: 875-886. DOI:10.2307/3236402
Zasada J C, Tappeiner Ⅲ J C, Maxwell B D, et al. 1994. Seasonal changes in shoot and root production and in carbohydrate content of salmonberry (Rubus spectabilis) rhizome segments from the central Oregon Coast Ranges. Canadian Journal of Forest Research, 24: 272-277. DOI:10.1139/x94-039
Zimmerman J K, Everham Ⅲ E M, Waide R B, et al. 1994. Responses of tree species to hurricane winds in subtropical wet forest in Puerto Rico, implications for tropical tree life histories. Journal of Ecology, 82: 911-922. DOI:10.2307/2261454