白林利, 韩文娇, 李昌晓

(西南大学生命科学学院,三峡库区生态环境教育部重点实验室,重庆400715)

模拟水淹对水杉苗木生长与生理生化特性的影响

白林利, 韩文娇, 李昌晓*

(西南大学生命科学学院,三峡库区生态环境教育部重点实验室,重庆400715)

通过对在不同土壤水分处理下水杉(Metasequoiaglyptostroboides)保护酶系[超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)、抗坏血酸过氧化物酶(ascorbate peroxidase,ASP)、过氧化氢酶(catalase,CAT)]活性及渗透调节物质(可溶性蛋白质、游离脯氨酸)和细胞膜脂过氧化产物[丙二醛(malondialdehyde,MDA)]含量以及光合特性、生物量的测定,探讨水杉对三峡库区水位变化的响应特性和耐水淹适应能力。模拟三峡库区消落带土壤水分变化格局,以二年生水杉苗木为试验材料,设置对照组(control,CK)、半淹组(half-submersion,HS)和全淹组(full-submersion,FS)3个处理。结果表明:在水淹胁迫下,SOD、POD、ASP、CAT活性以及游离脯氨酸含量均升高。在水淹胁迫下,水杉叶片MDA含量与CK相比差异不显著,无统计学意义。HS净光合速率(net photosynthetic rate,Pn)显著高于CK；FS的根冠比显著高于CK,但与HS相比差异不显著,无统计学意义。全淹植株呈叶芽形式,水淹植株存活率均达100%。在淹水期间,由于抗氧化酶、渗透调节物质、光系统Ⅱ的积极响应,水杉表现出极强的水分适应能力。因此,可以考虑将水杉列为三峡库区消落带植被构建的候选树种之一。

水杉； 水分胁迫； 生长； 生理生化

三峡工程给长江流域的生态环境带来了巨大影响[1],因三峡工程的兴建,三峡库区生态系统的水文循环、生物多样性格局和库区气候等正在发生着一系列改变[2],在库区消落带内人工构建植被、减少污染物质进入水体、保持库岸水土、维持和增强消落带的生态功能尤为重要。现有消落带与原有消落带相比,水淹时间更长、水淹程度更深,并且是在冬季水淹,这将很可能打乱库岸带植物的生理节律,影响这些库岸植物的光合作用与生长发育。重建和恢复消落带植被面临严峻的考验,而其中的关键就是对耐水淹树种的筛选[3]。因此,本文将耐水淹作为切入点,研究树种耐水淹的生理生化机制,为三峡库区消落带植被构建提供参考。

水杉(Metasequoiaglyptostroboides)是三峡库区库岸带典型的乡土树种,别称水沙,属杉科水杉属；其根系发达,耐寒与耐受多种水分逆境的能力较强,是亚热带地区平原绿化的优良树种[4]。目前对水杉的研究多集中于基因结构[5-7]、膜结构[8]、化学成分[9-14]、生长特性[15-17]和光合作用[18-19]等方面。但关于水杉对水分胁迫的响应缺乏生长、生化、光合特性的系统性研究,尤其是在三峡库区消落带土壤水分变化条件下水杉苗木的生理生态学特性鲜有报道,特别是对全淹条件下的变化情况不得而知。

本文拟对不同水淹深度下水杉的生长与生理生化特性进行研究,探索水杉在不同水淹条件下的生理生化响应机制,为其在三峡库区消落带高海拔地段栽植提供理论依据。

1 材料与方法

1.1 试验材料与处理方法

考虑到库岸防护林体系建设多采用二年生苗木,本试验以二年生的水杉苗木(取自四川省邻水县苗圃)为试验材料。2012年11月20日带土盆栽树苗(土壤类型为紫色土,其性质见表1),每盆1株(盆中央内径20 cm,盆高17 cm),共36株。置于西南大学三峡库区生态环境教育部重点实验室实验基地大棚(海拔249 m,透明顶棚,四周开敞)进行培养,于2013年1月18日进行试验处理[苗高(97.05±1.53) cm]。结合三峡库区消落带水位变化情况,设置对照组(control,CK)、半淹组(half-submersion,HS)和全淹组(full-submersion,FS)3个处理,每组12株。其中,CK为常规供水组,保持土壤含水量为田间持水量的75%～80%[2]；HS苗盆放入水池中,池水保持淹没至植物中段；FS苗盆也放入水池中,但池水保持没过植物顶端20 cm。于2013年4月3日结束试验进行各项指标的测定。

表1 供试土壤营养元素含量初始值

1.2 分析方法

2013年4月3日开始对不同处理组进行测定,每个处理组6株水杉苗木用于生长测定,6株用于生理生化测定。

1.2.2 生长与生物量测定 采用卷尺测量苗高、冠幅,用游标卡尺测量地径,每个处理6株,测定时间2013年4月3日。随后将试验盆钵中的苗木小心挖出,用自来水冲净根系,用根系分析仪(WinRHIZO,LC4800-Ⅱ LA2400)分析根系的总根长、总表面积和总体积。然后将根(收集断根,并用吸水纸吸干根表面水分)、茎、叶分别放置在80 ℃烘箱中烘干至恒重,用分析天平称量,计算根冠比。

1.2.3 生理生化指标的测定 2013年4月3日,将每个处理的6株水杉苗木叶片分别全部取完,保存于-80 ℃冰箱中,用于生理生化指标测定。超氧化物歧化酶(superoxide dismutase,SOD)活性测定采用氮蓝四唑(nitro-blue tetrazolium,NBT)法[24]。过氧化物酶(peroxidase,POD)活性测定采用愈创木酚法[24]。抗坏血酸过氧化物酶(ascorbate peroxidase,ASP)的测定采用文献[25]的方法。过氧化氢酶(catalase,CAT)活性测定采用过氧化氢氧化法,以每分钟内吸光值减少0.1为1个酶活力单位[24]。超氧根离子(O2-)测定采用高俊凤[26]的方法,以μg/g表示O2-的含量。丙二醛(malondialdehyde,MDA)含量的测定采用硫代巴比妥酸(thiobarbituric acid,TBA)氧化法,可溶性蛋白质含量测定采用考马斯亮蓝显色法,游离脯氨酸含量测定采用磺基水杨酸法,用茚三酮比色法测定其含量[24]。吸光值测定均采用紫外分光光度计。

1.2.4 数据处理 根据测定的各项指标,采用单因素方差分析(One-way ANOVA)揭示水分处理对水杉生长与光合生理的影响(GLM程序,SPSS 16.0),并用Tukey检验法进行多重比较,检验每个指标在处理间(α=0.05)的差异显著性，结果用平均值±标准误表示。

2 结果与分析

2.1 光合色素含量变化

不同处理对水杉苗木光合色素含量的影响显著(图1)。与CK相比,HS的叶绿素b(chlorophyll b,Chl b)、光合色素(photosynthetic pigments，Pp)均显著降低,分别降低35.06%和21.21%；叶绿素a(chlorophyll a,Chl a)、类胡萝卜素(carotene,Car)、叶绿素/类胡萝卜素(chlorophyll/yellow carotene,Chl/Car)亦降低,相比差异不显著,无统计学意义；而叶绿素a/b升高了22.89%,FS中的Chl a、Chl b、Car、Pp和Chl/Car却均显著低于CK与HS。与之相反,FS中的Chl a/b显著高于CK与HS。

2.2 光合指标

水淹结束时,与CK相比,HS中的Pn、CUE显著增加,而Sc、Ci/Ca则显著降低。HS中的Fv/Fm、PhiPS2有所增加,但与CK相比差异不显著,无统计学意义(表2)。因FS中的叶芽呈未展开形式,无法测定其光合参数.此外,各处理组水杉苗木存活率都达100%,即水淹未影响水杉树苗存活率。

2.3 渗透调节物质含量变化

在淹水胁迫下,水杉苗木体内脯氨酸含量不断积累,且随着胁迫程度的加剧积累越多。与CK相比,

CK:对照组;HS:半淹组;FS:全淹组.柱状图上的不同小写字母表示在0.05水平差异有统计学意义。 CK: Control; HS: Half-submersion; FS: Full-submersion. Different lowercase letters above the histogram indicate significant difference at the 0.05 probability level．图1 不同处理组光合色素的比较Fig.1 Comparison of photosynthetic pigments among treatment groups

表2 不同处理组光合参数的变化

Table 2 Changes of photosynthetic parameters among treatment groups

变量Variable对照组CK半淹组HSPn/[μmolCO2/(m2·s)]11.39±0.34b13.86±0.84aSc/[molH2O/(m2·s)]0.11±0.00a0.08±0.00bCi/Ca/(μmolCO2/mol)0.58±0.01a0.27±0.02bCUE=Pn/Ci0.05±0.00b0.16±0.02aFv/Fm0.77±0.00a0.78±0.00aPhiPS2=(F'm-Fs)/F'm0.08±0.00a0.09±0.00aETR39.98±1.10b46.70±1.17a

Pn：净光合速率；Sc：气孔导度；Ci：胞间CO2浓度；Ca：大气CO2浓度；CUE：羧化效率；Fv/Fm：光系统Ⅱ的最大量子产量；PhiPS2：光系统Ⅱ的实际量子产量；ETR：电子传递速率。同行数据后不同小写字母表示在0.05水平差异有统计学意义。

Pn: Net photosynthetic rate; Sc: Stomatal conductance; Ci: Intercellular CO2concentration; Ca: Atmospheric CO2concentration; CUE: Carboxylation efficiency;Fv/Fm: The maximum quantum yield of PSⅡ; PhiPS2: The actual quantum yield of PSⅡ; ETR: Electron transfer rate. Values within a row followed by different lowercase letters show significantly different at the 0.05 probability level.

HS和FS的游离脯氨酸含量均显著升高了34.46%和57.29%,而HS与FS相比差异不显著,无统计学意义;与CK相比,在水淹结束时,HS可溶性蛋白质升高,但未达显著水平,而FS则显著降低(图2).

2.4 叶片MDA与超氧根离子含量变化

在水淹结束时,HS、FS水杉苗木的MDA含量有所升高,但均与CK相比差异不显著,无统计学意义；与CK相比,HS、FS水杉苗木的超氧根离子均有所降低,但均未达显著水平(图3)。

2.5 叶片保护酶系活性变化

在水淹胁迫下,SOD表现为上升的趋势,HS显著高于CK,而FS与CK相比差异不显著,无统计学意义;与CK相比,HS、FS中的CAT活性均升高,但未达显著水平;不同水分处理对水杉苗木POD活性的影响显著,FS水杉苗木的POD活性显著高于CK,HS显著高于FS;与CK相比,HS、FS中CAT活性均升高,HS显著高于CK与FS(图3)。

CK:对照组;HS:半淹组;FS:全淹组.柱状图上的不同小写字母表示在0.05水平差异有统计学意义。 CK: Control; HS: Half-submersion; FS: Full-submersion. Different lowercase letters above the histogram indicate significant difference at the 0.05 probability level．图2 不同处理组脯氨酸、可溶性蛋白质含量的比较Fig.2 Comparison of free proline and soluble protein content among treatment groups

CK:对照组;HS:半淹组;FS:全淹组.柱状图上的不同小写字母表示在0.05水平差异有统计学意义。 CK: Control; HS: Half-submersion; FS: Full-submersion. Different lowercase letters above the histogram indicate significant difference at the 0.05 probability level．图3 不同处理组MDA、超氧根离子、SOD、POD、ASP、CAT的比较Fig.3 Comparison of MDA, O2-, SOD, POD, ASP, CAT among treatment groups

2.6 生长指标

2.6.1 苗高、地径、冠幅 在水淹结束时,各处理组的苗高、地径、冠幅都呈上升趋势；与CK相比,HS、FS苗高的净增长显著降低,地径的净增长与CK相比差异不显著,无统计学意义；HS水杉苗木冠幅的净增长显著高于FS,而与CK相比差异不显著,无统计学意义(图4)。

2.6.2 根长、根表面积、根体积 在水淹胁迫下,水杉苗木的根长,根表面积,根体积表现出一个共同的变化趋势,即与CK相比,HS升高,FS降低；HS水杉苗木的根长、根表面积显著高于FS,而与CK相比差异不显著,无统计学意义(图5)。

2.6.3 生物量分配 与CK相比,HS与FS的根所占比例显著升高;HS叶所占比例与CK相比差异不显著,FS茎所占比例与CK相比差异也不显著,无统计学意义。同时,FS的根冠比显著高于CK,但与HS相比差异不显著,无统计学意义(表3)。

CK:对照组;HS:半淹组;FS:全淹组.柱状图上的不同小写字母表示在0.05水平差异有统计学意义。 CK: Control; HS: Half-submersion; FS: Full-submersion. Different lowercase letters above the histogram indicate significant difference at the 0.05 probability level．图4 不同处理组水杉的苗高、地径、冠幅变化Fig.4 Changes of height, ground diameter, crown diameter of M. glyptostroboides among treatment groups

CK:对照组;HS:半淹组;FS:全淹组.柱状图上的不同小写字母表示在0.05水平差异有统计学意义。 CK: Control; HS: Half-submersion; FS: Full-submersion. Different lowercase letters above the histogram indicate significant difference at the 0.05 probability level．图5 不同处理组根长、根表面积、根体积的比较Fig.5 Comparison of root length, root surface area, root volume among treatment groups

表3 不同处理组水杉各器官在生物量中所占的比例

同行数据后的不同小写字母表示在0.05水平差异有统计学意义。

CK： Control; HS: Half-submersion； FS： Full-submersion. Values within row followed by different lowercase letters show significantly differences at the 0.05 probability level.

3 讨论

3.1 水淹对水杉苗木细胞膜的影响及其渗透调节物质的响应

渗透调节是植物适应逆境的一种重要的生理机制,植物通过代谢活动增加细胞内的溶质降低渗透势,维持膨压,从而使体内各种与膨压有关的生理过程正常进行[27-28]。脯氨酸被认为是有效的渗透调节物质之一,有助于细胞或组织持水[29]。在水淹胁迫下,水杉苗木游离脯氨酸含量增加(图2),超氧根离子含量与对照相比差异不显著(图3),表明水杉产生脯氨酸能适应水分胁迫,调节细胞的渗透势和清除活性氧[30]。FS可溶性蛋白质含量显著降低,HS有所增加,但未与CK产生显著差异(图2),说明全淹胁迫使水杉苗木的正常代谢过程受到干扰,抑制蛋白质的合成并诱导蛋白质的降解,从而使植株体内的蛋白质含量降低[31]；同时也表明水杉苗木对水淹逆境有一种内在的生理适应机制[32]。就本研究所测的渗透调节物质而言,从可溶性蛋白质含量相对较低,增幅平稳并没有对胁迫表现出明显增幅加大来看,脯氨酸是水杉应对水分胁迫较为主导的渗透调节物质,它对活性氧有专一的消除作用,可保护细胞膜免受损害[33]。

在水分胁迫下,植物体内丙二醛(MDA)和活性氧的产生及积累是植物的主要生理响应特征之一[34]。MDA是膜脂过氧化产物之一,其对细胞具有很强的毒性,并且参与破坏生物膜的结构和功能,通常利用其表示细胞膜脂过氧化程度及植物对逆境条件反应的强弱[35-36]。超氧根离子伤害植物的机制之一在于参与启动膜脂过氧化或脂膜脱酯作用[37],从而破坏膜结构。HS、FS水杉叶片MDA含量与CK相比差异不显著,说明水淹胁迫未对水杉苗木造成膜脂损害,显示出水杉具有良好的耐水淹特性。本研究同时发现,在淹水结束时,淹水处理组水杉苗木的O2-含量与CK相比差异不显著，SOD、POD、ASP和CAT均比CK高(图3),说明水杉苗木为了抵御水分胁迫的毒害作用,形成了复杂的抗氧化防御系统[38]。水杉苗木保护酶系统在短期内能维持活性氧的动态平衡,通过提高保护酶活性以加强清除活性氧、减少其对细胞膜伤害[36],这应是水杉苗木适应水淹环境的重要机制之一[39]。

3.2 水杉对水分胁迫的保护酶系统响应

SOD、POD、ASP和CAT是植物体内参与活性氧代谢的主要酶,SOD催化分解O2-,使之转化为过氧化氢(H2O2)；POD、ASP和CAT则被认为是植物清除H2O2的酶[40],它们的活性变化在一定程度上反映了植物体内活性氧的代谢情况[41]。在本研究中,HS水杉苗木的SOD、POD显著高于CK；而O2-含量、ASP和CAT均与CK相比差异不显著,表明在半淹胁迫下,水杉苗木启动SOD表达,产生大量的SOD清除O2-；在清除H2O2的过程中,POD起到了最主要的作用,这与Takemura等[42]对木榄(Bruguieragymnorrhiza)的研究结果相似,这些酶的表达是水杉苗木对水淹胁迫的适应性响应[43]。FS水杉苗木的SOD、O2-含量和CAT与CK相比差异均不显著,而POD、ASP显著高于CK,但POD显著低于HS。说明与半淹胁迫相比,在全淹胁迫下,水杉苗木主要通过升高ASP活性来清除H2O2,这应和其清除活性氧从而诱导提高保护酶活性与保护细胞膜有关,同时也是对水淹胁迫适应的结果[44]。

3.3 水杉对水分胁迫的光合与生长响应

水淹会使植株叶片的叶绿素降解,含量下降[45]。本研究发现,水淹使水杉苗木Chl、Car、Chl/Car下降,表明光合色素的降解是水杉苗木应对水淹胁迫的方式之一[46-47]。与CK相比,尽管水淹组水杉苗木Chl/Car下降,但其比值仍大于3(植物叶片内的叶绿素与类胡萝卜素含量之比通常约为3∶1[48]),提高了叶绿素在光合色素中的相对含量,确保有足够的反应中心色素,进而提高光合能力。而与CK相比,水淹组水杉苗木Chl a/b却显著上升(图1),表明水淹后水杉苗木的捕光色素降解得快,而光系统反应中心色素降解得慢[49],通过调节叶片Chl a与Chl b的比值来维持其较高的光合能力[50]。有研究表明,在水淹胁迫下,Chl a/b的比值上升[51],但也有研究认为下降[52]。本研究发现,淹水处理组的Chl a/b显著高于CK(图1),支持了Smethurst等[51]的研究结果。这极有可能是树种的不同所引起,不同的树种可能具有不同的耐水淹能力和响应特性,产生这种差异的原因还有待进一步研究。

植物叶片气孔变小甚至关闭是植物对水淹逆境胁迫的通常响应方式之一[53]。本研究发现,在水淹胁迫下,水杉苗木的Sc降低,与Mielke等[54]对美洲格尼帕树(Genipaamericana)的研究结果相同。罗芳丽等[55]认为水淹导致植株部分叶组织无法进行光合作用而使植株的整体光合能力受到影响,植株未被水淹的叶组织光合能力可能会增强。淹水后HS水杉苗木Pn显著高于CK(表2),其原因可能是植物的光合能力受光合产物需求的负反馈调节[56],这可能与水杉叶片在水淹期间具有较高羧化能力有关(表2),也是水杉苗木抗氧化酶、渗透调节物质与光合色素综合作用的结果。本研究发现,与CK相比,HS水杉苗木的Pn增加了33%,高于相同水淹深度处理后耐淹树种水翁(Cleistocalyxoperculatus)[57]和落羽杉(Taxodiumdistichum)[58]。可见,在短暂的水淹时间(2013-01-18—2013-04-03)内,水杉苗木与一些耐淹树种相比其光合能力受水淹影响较小。本研究还发现,在半淹胁迫下,水杉苗木的Pn、Sc和Ci/Ca的变化(表2)表明,水杉苗木Pn升高的原因极有可能是在短期水淹胁迫下水杉苗木的光合酶活性和利用CO2的能力较强所致[59]。

叶绿素荧光检测可以快速、灵敏地了解植物光合作用对外界环境因子的响应[60],植物叶片PSⅡ的最大光化学效率(Fv/Fm)可以作为PSⅡ潜在光化学活性的度量,在非胁迫条件下该参数变化极小,不受物种和生长条件的影响；在胁迫条件下该参数明显下降,表明有功能的反应中心含量降低[55]。HS水杉叶片的Fv/Fm与CK相比差异不显著,表明半淹胁迫对水杉有功能的PSⅡ反应中心影响较小,加之水杉苗木抗氧化系统与光合色素的积极响应,表明水杉确实有较强的水分适应能力[61]。与CK相比,HS水杉苗木有较高PhiPS2、电子传递速率(表2),表明水淹对水杉叶片光合器官及羧化酶的活性影响较小。

植物的生物量、苗高和地径与其生长发育及营养物质的形成密切相关,对其所处的生长环境综合表征作用明显[62]。本研究发现,不管是HS还是FS,水杉苗木苗高的净增长都低于CK,淹水胁迫抑制了植物苗高的生长[63]。本研究还发现,半淹胁迫对水杉的生长具有部分促进作用,与东北玉簪(Hostaclausa)[64]和乌桕(Sapiumsebiferum)[65]等表现相似。HS水杉根长、根表面积均比CK高,HS叶所占的比例,地径、冠幅的净增长与CK相比差异不显著,这有可能与半淹胁迫下水杉苗木Pn显著高于CK有关。而水淹组水杉苗木根所占比例,根冠比显著高于CK(表3),说明二年生水杉苗木生物量较多分配在根部,加大根部化合物的贮存,以有效应对水淹胁迫下逆境条件[66-67]。

4 结论

本研究发现,水杉苗木的生长和生理生化代谢受到水淹胁迫的影响,其水分适应性较强。在水淹胁迫下,水杉苗木引起膜脂过氧化以及光合色素含量降低,但由于体内渗透调节物质含量的增加和抗氧化防御系统的积极防御,可以缓解过多水分对水杉苗木造成的损害,从而没有对Fv/Fm和Pn造成影响。在不同淹水条件下,水杉苗木存活率均达100%,表现出极强的适应水环境的能力。从本研究结果来看,水杉可以作为三峡库区消落带植被恢复的候选树种之一。

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Effects of simulated waterlogging on growth, physiological and biochemical characteristics ofMetasequoiaglyptostroboidesseedlings.

Bai Linli, Han Wenjiao, Li Changxiao*

(KeyLaboratoryfortheEco-EnvironmentoftheThreeGorgesReservoirRegionoftheMinistryofEducation,CollegeofLifeSciences,SouthwestUniversity,Chongqing400715,China)

The disruption of natural flow regimes in river systems poses many challenges to riparian ecosystems and their native species. The construction of the Three Gorges Dam has altered the flow regimes of the upper Yangtze River and created a riparian zone with a vertical gap of 30 m. Because of the anti-seasonal change of the water level caused by annual water regulation, plants grown on the riparian zone of the Three Gorges Reservoir Area (TGRA) may suffer from submergence, and often display dynamic change characteristics. Such water level change is likely to disturb the normal ecophysiological rhythm of the native tree species of the riparian zone. These hydrological changes highlight the importance of screening suitable tree species for reforestation in the TGRA and similar environments. Thus, the native tree speciesMetasequoiaglyptostroboides, will most likely to experience continuous submergence or inundation. Current research onM.glyptostroboidesseedlings is more focused on genetic structure, membrane composition, chemical property, growth and photosynthesis, and the like. However, the eco-physiological implications of submersion onM.glyptostroboidesseedlings are not well known, especially under the condition of full-submersion.

The aim of this study was to investigate the responding characteristics of theM.glyptostroboidesseedlings to the water level change in the TGRA, and provide theoretical basis for species selection for revegetation in the riparian zone of the TGRA.

Measured indexes included protective enzymes such as superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (ASP) and catalase (CAT), osmotic adjustment substances such as soluble protein and free proline, and membrane lipid peroxidation such as malondialdehyde (MDA), as well as photosynthetic characteristics and biomass accumulation of the two-year oldM.glyptostroboidesseedlings to submergence, upon mimicking the water level change in the riparian zone of the TGRA. Based on soil moisture change pattern in the TGRA, water treatments including control (CK), half-submersion (HS), and full-submersion (FS) were applied.

The activities of SOD, POD, ASP, CAT and content of free proline ofM.glyptostroboidesseedlings in HS and FS group were higher than that in CK after submersion. Under submersion, MDA content in HS and FS group increased as compared with that in CK. The net photosynthetic rate ofM.glyptostroboidesseedlings in HS was significantly higher than that in CK. Root-shoot ratio in FS was significantly higher than that in CK, but no significant difference was detected between FS and HS. Leaves ofM.glyptostroboidesseedlings in FS were leaf bud, and survival rates were 100%.

The results indicated that antioxidant enzymes, osmotic adjustment substances and photosystem Ⅱ have a positive response during submersion,M.glyptostroboidesseedlings show strong adaptability to the submersion. Thus,M.glyptostroboidesshould be considered as one of the potential species for revegetation in the TGRA.

Metasequoiaglyptostroboides; water stress; growth; physiology and biochemistry

Journal of Zhejiang University (Agric. & Life Sci.), 2015,41(5):505-515

重庆市基础与前沿研究计划重点项目(CSTC2013JJB00004)；中央高校基本科研业务费专项资金(XDJK2013A011)；国家林业公益性行业科研专项(201004039)；留学回国人员科研启动基金(教外司留[2010]1561号)。

联系方式:白林利(http://orcid.org/0000-0002-0956-844X),E-mail:895845358@qq.com

2014-09-29;接受日期(Accepted):2015-01-21；网络出版日期(Published online):2015-09-18

Q 945.78; S 718.43; S 791.35

A

*通信作者(Corresponding author):李昌晓(http://orcid.org/0000-0002-5090-6201),E-mail:lichangx@swu.edu.cn

URL:http://www.cnki.net/kcms/detail/33.1247.s.20150918.1743.004.html