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1.
干旱胁迫对高山柳和沙棘幼苗光合生理特征的影响   总被引:2,自引:0,他引:2  
蔡海霞  吴福忠  杨万勤 《生态学报》2010,30(9):2430-2436
为了解干旱河谷-山地森林交错带植物光合生理特征对干旱胁迫的响应。以交错带两种典型植物高山柳(Salix paraqplesia)和沙棘(Hippophae rhamnoides)为研究对象,研究其在不同程度的干旱胁迫条件下植株气体交换参数的日变化特征。干旱胁迫显著降低了两种植物叶片数、叶面积、叶片生物量、比叶面积、色素含量、净光合速率(Pn)、气孔导度(gs)和气孔限制值(Ls)等与光合生理过程密切相关的叶片指标,但增大了胞间CO2浓度(Ci)和内禀水分利用效率(WUEi)。植物叶片的气体交换参数(如:Pngs)日变化并未完全随着光合有效辐射的增强和温度的升高而增加,全天以11:00最大,"午休"现象明显。相对而言,沙棘在干旱胁迫条件下表现出相对较高的叶面积、PngsWUEi,具有相对更强的适应干旱环境的能力,而高山柳对干旱胁迫更为敏感。  相似文献   

2.
干旱胁迫对玉米苗期叶片光合作用和保护酶的影响   总被引:25,自引:0,他引:25  
以玉米品种郑单958(抗旱性强)和陕单902(抗旱性弱)为材料,采用盆栽控水试验,设置3个干旱处理(轻度干旱,中度干旱,重度干旱)和正常灌水,研究了干旱胁迫对玉米苗期叶片光合速率、叶绿素荧光以及相关生理指标的影响。结果表明:(1)干旱胁迫下2个品种叶片净光合速率(Pn)和气孔导度(Gs)显著下降,胞间CO2浓度(Ci)出现了先下降后上升,而气孔限制值(Ls)上升后下降,说明中度干旱胁迫下叶片Pn下降是气孔因素引起的,重度干旱胁迫下Pn降低主要由非气孔因素引起的。(2)随着干旱胁迫的加剧,2个品种叶片光系统Ⅱ(PSⅡ)的实际量子产量(φPSⅡ)、电子传递速率(ETR)和光化学猝灭(qP)一直下降,而非光化学猝灭(qN)上升后下降,说明中度干旱下热耗散仍是植株重要光保护机制,重度干旱时叶片光合电子传递受阻,PSⅡ受到损伤。(3)干旱胁迫下2个品种叶片的超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性先升高后降低,而丙二醛(MDA)含量一直升高,说明干旱胁迫初期对保护系统酶活性升高有诱导作用,重度胁迫下活性氧清除酶的活性下降,导致细胞膜伤害。这些结果暗示,轻度和中度干旱胁迫下2个玉米品种通过减少光捕获、热耗散和酶活性调节协同作用稳定了光合机构功能,是Pn下降的气孔限制因素;而重度干旱胁迫下光系统Ⅱ和抗氧化酶系统损伤,是Pn下降的非气孔限制因素;郑单958的各生理参数比陕单902受旱影响小,干旱胁迫下仍具有较高的光合效率和较强的保护酶活性是郑单958抗旱的主要生理原因。  相似文献   

3.
珍稀药用植物白及光合与蒸腾生理生态及抗旱特性   总被引:1,自引:0,他引:1       下载免费PDF全文
吴明开  刘海  沈志君  罗鸣  吴沿友 《生态学报》2013,33(18):5531-5537
以珍稀濒危药用植物白及(Bletilla striata)叶片为研究对象,应用Li-6400XT便携式光合仪分别在晴天和阴天进行光合生理生态特性研究。结果显示晴天GsPnTr日变化呈现双峰型,阴天为单峰型;光合-蒸腾具有极显著线性正相关关系与良好的线性耦合关系(晴天和阴天的相关系数分别为0.883**、0.954**,回归直线斜率分别为2.38、3.78);PAR-PnPAR-TrTl-PnTl-TrGs-PnGs-Tr 的回归直线形态非常相似,除晴天TlPn外,其余两两相关关系均达到了显著水平;PARTlGs三个因子与PnTr均表现为正相关关系,其中Gs是调控PnTr的最主要因子。进行聚乙二醇6000(PEG6000) 渗透胁迫实验以评价白及抗旱能力,分析不同质量分数PEG6000(0、5、20、40、60g/L)下的白及幼苗叶绿素含量、叶片含水量、相对电导率3个生理指标,结果表明叶绿素含量与与胁迫浓度呈负相关(R2=0.7854),随着PEG质量分数的增加,叶片的叶绿素含量持续显著下降;叶片含水量与胁迫浓度呈负相关(R2=0.9936);相对电导率与与胁迫浓度呈正相关(R2=0.8755),相对电导率会随着PEG质量分数的增加而显著增加。试验结果综合分析显示白及为耐荫植物,抗旱能力不强。白及进行人工栽培应适当遮阴保持土壤与空气湿度。  相似文献   

4.
利用盆栽试验结合人工浇水后自然耗水的方法测定干旱胁迫对梭梭、白刺、沙蒿3种荒漠植物叶片水分、光合及叶绿素荧光参数的影响,探讨各指标在干旱胁迫过程中的变化特征、响应机制及其与土壤水分的定量关系,并用隶属函数法对其进行抗旱性排序。结果表明:(1)3种植物叶片相对含水量(RWC)随干旱胁迫天数增加持续降低,最大水分亏缺(RWD)呈波动式上升趋势。(2)3种植物总叶绿素含量(Chl)和叶绿素a(Chla)、叶绿素b(Chlb)含量,以及梭梭、白刺类胡萝卜素含量均随胁迫天数增加而降低;沙蒿类胡萝卜素随土壤含水率降低逐渐升高。(3)梭梭、白刺、沙蒿叶片净光合速率(Pn)、蒸腾速率(Tr)、水分利用效率(WUE)等主要光合气体交换参数对土壤水分表现出明显的阈值响应,适宜的土壤含水率分别为8.04%~19.33%、4.17%~19.10%、6.48%~17.51%。(4)3种植物 PSⅡ最大光化学效率(Fv/Fm)、实际光化学效率(Fv′/Fm′)及光化学淬灭系数(qP)均随干旱胁迫天数增加和光照强度增大而降低,非光化学淬灭系数(NPQ)则呈逐渐上升趋势;干旱胁迫中后期,梭梭、沙蒿的Fv/FmFv′/Fm′均下降,光合机构光合活性遭到破坏,电子传递受阻,PSⅡ反应中心受损,表现出光抑制,而白刺调节自身PSⅡ反应中心免受伤害的能力较强。(5)隶属函数法综合分析表明,3种植物耐旱能力大小依次为白刺>梭梭>沙蒿。研究发现,3种荒漠植物均可通过调节 PSⅡ反应中心开放程度与活性,对干旱胁迫表现出较强的耐性,胁迫后期植物PSⅡ反应中心关闭或不可逆失活,表现出光抑制。  相似文献   

5.
香梨两种树形净光合速率特征及影响因素   总被引:4,自引:0,他引:4       下载免费PDF全文
孙桂丽  徐敏  李疆  梅闯 《生态学报》2013,33(18):5565-5573
以自然开心形和疏散分层形香梨树为试材,应用美国Li-cor公司生产的Li-6400光合作用测定系统测定其光合参数,分析了香梨两种不同树形叶片的光合特性以及叶片叶绿素含量、比叶重(SLW)与净光合速率(Pn)的关系,同时研究了气孔导度(Gs)、胞间CO2浓度(Ci)、蒸腾速率(Tr)及其它因子对不同树形Pn的影响。结果表明:自然开心形和疏散分层形香梨树叶片Pn日变化呈不对称双峰曲线,14:00左右出现光午休现象,且整个生长期疏散分层形香梨树叶片Pn峰值大于自然开心形,6月份Pn最小,这与气孔的调节作用密切相关。疏散分层形Pn日变化在11:00 和15:30出现高峰,自然开心形Pn日变化高峰出现在11:00和17:00;同一品种同一时期的自然开心形树和疏散分层形树的叶绿素含量与其Pn值呈正相关,R2分别为0.9438和0.8952;自然开心形的PnSLW的相关性高于疏散分层形;Gs、TrRHPn呈正相关,与Ci、CsPn呈负相关,且疏散分层形香梨树叶片的PnGs、TrCs的相关性均达到了极显著水平,与Ci、Ta、PARHs均达到了显著水平,而在自然开心形中Pn与光合参数相关性不明显,这说明疏散分层形香梨树对影响光合作用的外界因素和内部因素的变化反应比自然开心形敏感。  相似文献   

6.
李文娆  李小利  张岁岐  山仑 《生态学报》2011,31(5):1323-1333
利用聚乙二醇(PEG-6000)模拟水分亏缺条件(胁迫水势-0.2MPa,胁迫48h),研究了变水条件下紫花苜蓿(品种:阿尔冈金和陇东)和高粱(品种:抗四)根系水力学导度(Lpr)、根系活力、根叶相对含水量、水分利用效率等参数的动态变化,以期进一步明确植物水分吸收及散失过程调控的生理生态学基础。结果表明:水分亏缺限制了紫花苜蓿和高粱根系吸水,表现在Lpr的下降和根系活力的降低;继而调控了其地上部反应,引起气孔导度、光合速率、叶片相对含水量和蒸腾速率等的下降,但限制性的提高了其水分利用效率,尤其在胁迫初期。恢复到正常供水条件后,Lpr、根系活性、气孔导度等水分利用参数逐渐部分或完全恢复到了胁迫前水平,但恢复程度存在种间和品种间差异,并且根系吸水能力的恢复对于是植株地上部生长状态的恢复至关重要,尤其是水分恢复初期。紫花苜蓿根系中检测到水通道蛋白(AQPs)的存在,水分亏缺对紫花苜蓿Lpr的影响认为主要是通过影响AQPs的活性实现的。比较紫花苜蓿和高粱水分吸收与利用状况在变水条件下的动态变化,认为紫花苜蓿幼苗对干旱逆境的适应能力相对弱于高粱,品种间陇东适应能力更强。  相似文献   

7.
刘涵  孙冲  黄威  黄勤琴  吴杰  刘霞 《西北植物学报》2023,43(2):1866-1871
该研究在人工控制水分条件下,设置3个干旱胁迫处理,选用3个主栽油菜品种‘陇油10号’、‘陇油2号’、‘青杂5号’幼苗进行盆栽试验,测定干旱胁迫条件下叶片相对含水量、叶绿素含量、光合气体交换参数及叶绿素荧光参数等指标,考察各指标在干旱胁迫过程中的变化特征,并通过主成分分析(PCA)和隶属函数法评价品种的抗旱性及其主要响应因子,以揭示西北地区油菜幼苗响应干旱胁迫的光合调控机制。结果表明:(1)各品种油菜幼苗的叶片相对含水量(RWC)均随干旱胁迫程度的递增而逐渐降低,最大水分亏缺(WSD)却逐渐上升。(2)各品种油菜幼苗叶片的叶绿素a含量、叶绿素总含量随着干旱胁迫程度的递增而先增加后递减,且同一种幼苗在不同处理间差异显著。(3)各品种油菜幼苗叶片的净光合速率(Pn)、水分利用效率(WUE)、单株生物量、气孔导度(Gs)、胞间CO2浓度(Ci)均在受到干旱胁迫时迅速降低,且同一品种幼苗在不同处理间差异显著,而其叶片蒸腾速率(Tr)在干旱胁迫下无显著变化。(4)各品种油菜幼苗叶片光化学猝灭系数(qP)和非光化学猝灭系数(NPQ)随着干旱胁迫程度的递增先增加后递减,最大光化学效率(Fv/Fm)和电子传递速率(ETR)在受到干旱胁迫时迅速降低,且同一品种幼苗在不同处理间差异显著。(5)主成分分析结果表明,在油菜幼苗受到干旱胁迫时RWCCiGsPnWUE、叶绿素总含量、叶绿素a含量和NPQ起主要调控作用;隶属函数法综合评价表明,3个品种油菜幼苗耐旱能力由高到低依次为‘陇油10号’>‘陇油2号’>‘青杂5号’。  相似文献   

8.
运用压力室-容积技术(P-V技术)对西鄂尔多斯地区特有的濒危植物四合木(Tetraena mongolica Maxim.)和生长于同一生境的近缘种霸王(Zygophyllum xanthoxylon (Bunge) Maxim.)的7个水分关系参数饱和含水量时最大渗透势(Ψssat) 、初始质壁分离时的渗透势(Ψstlp) 、初始质壁分离时渗透水相对含量(ROWCtlp) 、初始质壁分离时的相对含水量(RWCtlp) 、质外体水的相对含量(AWC) 、束缚水与自由水的比值(Va / V0),以及细胞最大弹性模量(εmax)进行了测定,同时利用Li-6400光合作用测定系统测定了二者叶片气体交换参数的日变化,从生理生态学角度探讨了二者生存力、适应力的差异。结果表明:1)四合木的εmax、ROWCtlp值和RWCtlp值均显著低于霸王,而ΨssatΨstlp值、AWC和Va / V0高于霸王。二者保持膨压的能力和方式不同,四合木表现为较小的细胞体积和较强的持水能力,主要以高的组织弹性来保持膨压,而霸王主要以增加细胞质浓度的渗透调节来维持膨压,弹性调节较弱。且四合木保持最大膨压的能力和维持最低膨压的极限渗透势低于霸王,耐旱性弱于霸王。2)自然条件下,四合木和霸王叶片的光合速率(Pn)、蒸腾速率(Tr)日进程均呈"双峰"曲线,主峰出现在11:00时,次峰出现在15:00时左右,光合作用的午间降低是由气孔导度(Gs)降低造成的。二者相比,四合木光合速率和水分利用效率(WUE)低于霸王,光合能力和对干旱环境适应能力弱于霸王。研究表明四合木在生理生态学方面的生存力、适应力弱于霸王。  相似文献   

9.
城市遮阴环境变化对大叶黄杨光合过程的影响   总被引:1,自引:0,他引:1       下载免费PDF全文
于盈盈  胡聃  郭二辉  肖强  柳敏  张小飞 《生态学报》2011,31(19):5646-5653
城市遮阴与自然生态系统遮阴环境不同,它由城市中的建筑、基础设施等人工构筑物所产生,并对植物光合过程产生影响。采用Li-6400便携式光合作用测定系统对北京市不同建筑遮阴环境下的生态因子特征及大叶黄杨光合参数特性进行了现场实验对比观测与分析。研究显示:(1)城市建筑或基础设施布局或格局变化导致建筑遮阴环境光、温等生态因子的差异性变化,主要体现在光合有效辐射(PAR)在时间分布及强度上的显著差异。(2)遮阴改变大叶黄杨的光合参数,日净光合速率曲线为不规则单峰型,由遮阴进入太阳直射时,净光合速率(Pn)明显升高,随遮阴程度加重峰值时间有后延现象,完全遮阴时净光合速率最低。(3)大叶黄杨叶片在有一定时间太阳直射的中度遮阴(2.3h和5.5h)下适应性良好,日均净光合速率、光补偿点(LCP)、光合能力(Pnmax)、叶面积(LA)、比叶重(LMA)没有显著差异,植物主要通过光合色素含量及组成的改变来适应太阳直射时间变短(2.3h)的遮阴环境。(4)遮阴改变植物的光暗适应策略,没有阳光直射的重度遮阴下,大叶黄杨通过其光合、形态、光合色素等多方面的改变来适应遮阴环境,建筑重度遮阴严重影响植物光合过程。探讨了不同程度建筑遮阴对植物光合作用的影响及植物的适应机制,为基于提高其生态服务功能的树种配置和城市规划提供科学依据。  相似文献   

10.
为了分析干旱环境下地下水埋深变化对胡杨(Populus euphratica oliv.)光合作用的影响,对塔里木河下游3个地下水埋深(4.91,6.93m和8.44m)环境下胡杨叶片的气体交换日变化、光响应曲线、PN-Ci曲线以及叶绿素荧光特性等进行了比较研究。研究结果表明:当地下水埋深从4.91m增加到6.93m和8.44m,胡杨光合速率(PN)(10:00),初始荧光(F0)、最大荧光(Fm)、以及PSⅡ实际光化学效率(ΩPSⅡ)、电子传递速率(ETR)、非光化学猝灭系数(NPQ)和正午叶水势(Ψmidday)等都发生了明显变化,其中胡杨NPQ增加了109% 127%,ΩPSⅡ,ETRΨmidday分别减小了24% 29%,17% 22%和31.6% 45.6%,表明胡杨受到的干旱胁迫程度在增加;而当地下水埋深在6.93 8.44m之间时,上述参数无显著变化,表明胡杨很可能处于相同干旱胁迫程度;并且在地下水埋深4.91 8.44m范围内,最大光化学效率(Fv/Fm),表观量子效率(φ),Rubisco羧化速率(Vcmax), 等参数都未发生明显变化,表明即使地下水埋深增加到8.44m,此时的干旱胁迫程度也未超过胡杨的耐受能力,其光合能力也未受到不可逆转的伤害。  相似文献   

11.
Fang J M  Wu F Z  Yang W Q  Zhang J  Cai H X 《农业工程》2012,32(4):195-201
Anthropogenic activities and environmental changes have had a significant effect on the fishery ecosystem, biological characteristics, and population dynamics of marine fishes. Overfishing threatens the sustainability of many populations. We evaluated changes in the biological characteristics, distribution, and abundance of Cleisthenes herzensteini using bottom trawl survey data collected from 1985 to 2010 in the central and southern Yellow Sea. The dominant body length of C. herzensteini during spring was 80–160 mm in 1986, 60–160 mm in 1998, and 41–80 mm and 111–170 mm in 2010. During summer, the dominant body length was 80–180 mm and 130–169 mm in 2000 and 2007, respectively. During autumn, the dominant body length was 60–160 mm, 100–180 mm, and 90–149 mm in 1985, 2000, and 2009, respectively. During winter, the dominant body length was 80–200 mm, 120–220 mm, and 100–200 mm in 1985, 1999, and 2010, respectively. The dominant body length decreased gradually from 1985 to 2010 (excluding spring, 2010), illustrating the “miniaturization” of the C. herzensteini population. Growth was significantly different between male and female individuals, with male individuals forming a “smaller-size type”. The sex ratio of C. herzensteini was relatively stable during spring and summer, but significantly different during autumn and winter. The diet of C. herzensteini also changed significantly from 1985 to 2010. During 1985–1986, the diet consisted primarily of Crangon affinis, Eualus sinensis and Gammaridae species. C. affinis, Engraulis japonicus, and Ammodytes personatus were dominant during 1998–2000, whereas C. affinis was the dominant prey species during 2009–2010. Thus, there was a clear decrease in dietary diversity, with a shift to benthos shrimp, particularly C. affinis, which accounted for 82.58% of the total diet (by weight) in 2010. The gastric vacuous rate also decreased in every season and the gonad developmental stage changed with each season. The distribution of C. herzensteini shifted northward and offshore and became more concentrated. The average catch per haul of C. herzensteini decreased in spring and autumn. The average catch per haul ranged from 1.44 kg h-1 to 0.14 kg h-1 in spring and the percentage by weight ranged from 6.53% to 1.28%. The average catch per haul ranged from 3.03 kg h-1 to 0.26 kg h-1 in autumn and the percentage by weight ranged from 8.00% to 0.60%. The average catch per haul increased significantly during summer, ranging from 0.18 kg h-1 to 0.58 kg h-1, with a percentage by weight of 0.03–0.80%. The average catch per haul was relatively stable in winter (around 1.00 kg h-1), but the percentage by weight gradually increased during 1985–2010. Taken together, our results suggested that the population structure, diet composition, and distribution of C. herzensteini had been altered during the last three decades. To address this, it is essential to initiate measures to conserve the C. herzensteini resource.  相似文献   

12.
高温胁迫对不同种源希蒙得木叶片生理特性的影响   总被引:6,自引:0,他引:6  
利用人工气候室模拟高温环境,研究了不同程度高温处理对3个不同种源(Z1:会东可河;Z2:澳大利亚肯多伯冷;Z3:美国菲尼克斯)希蒙得木叶片相对含水量(LRWC)、叶片光合特性、渗透调节、抗氧化保护酶、膜脂过氧化的影响.结果表明,3个种源希蒙得木幼苗LRWC、净光合速率(Pn)和蒸腾速率(Tr)均随高温胁迫强度的加剧呈极显著下降趋势,叶绿素含量(Chl)、可溶性糖含量显著降低;脯氨酸(Pro)含量呈极显著上升趋势;丙二醛(MDA)含量和相对电导率(REC)均随高温胁迫强度的加剧而显著增加;高温胁迫对希蒙得木幼苗叶片过氧化物酶(POD)活性和超氧化物歧化酶(SOD)活性的影响因种源不同而有所差异,Z1、Z2的POD活性随高温胁迫程度的增加而持续上升,Z3的POD活性呈先上升后降低趋势;Z1、Z3的SOD活性随高温胁迫程度的增加而持续上升,Z2的SOD活性呈先降低后上升趋势.以隶属函数法综合分析各种源希蒙得木幼苗抗高温能力的结果表明,3个种源希蒙得木幼苗的抗高温能力由强到弱依次为:Z1、Z3和Z2.结果表明,长期生长在金沙江干热河谷的Z1可能已经适应当地的生态环境,表现出较好的抵御高温的能力,不同种源耐高温能力的差异可能是通过种源所在地的气候、土壤、海拔等因子综合作用,经过漫长的系统发育,产生不同的变异结果.  相似文献   

13.
郭卫华  李波  张新时  王仁卿 《生态学报》2007,27(10):4132-4140
多年生灌木沙棘和中间锦鸡儿是黄土高原生态重建的重要物种,设计人工模拟水分胁迫实验,测量沙棘和中间锦鸡儿蒸腾作用的各种指标,研究其蒸腾特性对水分胁迫的适应方式。结果表明,同等水分处理条件下,中间锦鸡儿单叶水平上的蒸腾速率高于沙棘。沙棘和中间锦鸡儿的蒸腾速率日进程在晴天、阴雨天和生长发育的不同阶段明显不同。夜间蒸腾占全天蒸腾的比例相当大,夜间蒸腾在不同物种之间、不同供水量之间存在明显差异,而且越干旱的环境比例越大。两种植物气孔阻力的季节变化格局在不同水分处理间大体相似。沙棘的昼夜蒸腾节律在各种水分处理条件下都表现出明显的气孔振荡现象,而中间锦鸡儿没有。叶片温度、光合有效辐射和气孔阻力是各种水分条件下沙棘和中间锦鸡儿蒸腾作用的共同的限制因子,相对于沙棘,中间锦鸡儿还更多地受到空气相对湿度的影响。  相似文献   

14.
Enhanced ultraviolet-B (UVB) radiation and water deficit affect plant growth and development. We determined the effects of UVB and drought stress on growth parameters and chemical attributes of two ecotypes (alpine and prairie) of Stellaria longipes under controlled-environment conditions. Clonal ramets of these ecotypes were grown under three UVB levels (0, 5, and 10 kJ m−2 d−1) and exposed to two watering regimes (well watered and drought stressed) for 21 days. Compared to the alpine, the prairie ecotype was taller, had higher number of nodes, and greater leaf area and specific leaf weight (leaf dry weight: leaf area), which resulted in increased dry matter in this ecotype. Overall, ‘prairie’ was higher in total chlorophyll (Chl), but lower in Chla:b ratio, flavonoids, and ethylene, than ‘alpine’. In both ecotypes, UVB and drought stress reduced growth and dry matter, whereas UVB increased carotenoids and flavonoids. Drought stress decreased ethylene evolution. These characteristics were also determined in plants growing in the field. In the field-growing plants, ‘prairie’ had higher growth and dry matter, but lower Chla:b ratio and flavonoids, than ‘alpine’. The two ecotypes responded differentially to UVB and watering regime, as ‘prairie’ appeared to be more sensitive to UVB and drought stress than ‘alpine’.  相似文献   

15.
The effect of an arbuscular mycorrhizal fungus “AMF” (Glomus constrictum Trappe) on growth, pigments, and phosphorous content of marigold (Tagetes erecta) plant grown under different levels of drought stress was investigated. The applied drought stress levels reduced growth vigor (i.e. plant height, shoot dry weight, flower diameter as well as its fresh and dry weights) of mycorrhizal and non-mycorrhizal plant as compared to control plant (non-drought stressed plant). The presence of mycorrhizal fungus, however, stimulated all growth parameters of the treated plant comparing to non-mycorrhizal treated plant. The photosynthetic pigments (carotene in flowers and chlorophylls a and b in leaves) were also stimulated by the mycorrhizal fungi of well-watered as well as of water-stressed plants. The total pigments of mycorrhizal plants grown under well-watered conditions were higher than those of non-mycorrhizal ones by 60%. In most cases, drought-stressed mycorrhizal plants were significantly better than those of the non-mycorrhizal plants. So, the overall results suggest that mycorrhizal fungal colonization affects host plant positively on growth, pigments, and phosphorous content, flower quality and thereby alleviates the stress imposed by water with holding.  相似文献   

16.
李茜  刘增文  米彩红 《生态学报》2012,32(19):6067-6075
通过采集树木枯落叶与土壤进行室内混合分解培养试验,研究了黄土高原常见的樟子松和落叶松与其他树种枯落叶混合分解对土壤性质的影响及存在的相互作用,从而为不同树木种间关系的探索和该地区人工纯林的混交改造提供科学指导。结果表明:12种枯落叶单一分解均明显提高了土壤脲酶(54%—110%)、脱氢酶(85%—288%)和磷酸酶(81%—301%)活性以及有机质(29%—55%)和碱解N(12%—49%)含量,但对土壤速效P含量和CEC的影响存在较大差异。综合而言,樟子松分别与白桦、刺槐、白榆、柠条和落叶松枯落叶混合分解在对土壤性质的影响中存在相互促进作用,而分别与小叶杨、沙棘、紫穗槐、侧柏和辽东栎枯落叶混合分解在对土壤性质的影响中存在相互抑制作用;落叶松分别与刺槐、白桦、小叶杨和紫穗槐枯落叶混合分解在对土壤性质的影响中存在相互促进作用,而分别与柠条、侧柏、辽东栎、沙棘、油松和白榆枯落叶混合分解在对土壤性质的影响中存在相互抑制作用。  相似文献   

17.
Outdoor pot experiments were conducted in California to quantify differences in rice and Schoenoplectus mucronatus susceptibility to drought and to identify morphological and physiological traits that would favor rice over S. mucronatus under drought. Plants were grown in flooded soil for approximately 5 weeks, and then subjected to different drought periods after which pots were re-flooded. Chlorophyll fluorescence assays revealed that rice and S. mucronatus Fv/Fm first became <0.8 after leaf water potential (Ψleaf) had decreased to approximately −4 MPa and −2 MPa, respectively. Thus, by suffering less photosynthetic damage from drought, rice had better recovery after re-flooding than S. mucronatus. When drought reduced Ψleaf to −3 MPa, S. mucronatus re-growth was nearly suppressed but that of rice was unaffected. Rice plants depleted soil moisture 1.6 faster than S. mucronatus due to larger and deeper roots and a high water-spending strategy (when Ψleaf decreased from approximately −0.5 MPa to −2.5 MPa, 13δ increased from −27.8 to −27.4 and from −28.1 to −26.0 for rice and S. mucronatus, respectively). Rice under interspecific competition sustained its Ψleaf by extracting more water from greater depths, while causing severe moisture stress and photosynthetic damage to S. mucronatus. Thus temporary drought enhanced rice competitiveness over S. mucronatus, supporting the concept of using brief drought as a tool for S. mucronatus suppression in rice. The Ψleaf developed by the end of the drought period predicted rice yields (R2 = 0.77, P < 0.0001) and the capacity of S. mucronatus to recover from drought upon irrigation resumption (R2 = 0.62, P < 0.001). Brief (8-10 d) drought imposed on 5-week-old rice did not significantly depress late-season rice biomass growth or grain yields, while S. mucronatus never fully recovered from drought. Rice yields were only reduced after Ψleaf reached values below approximately −2.5 MPa. Longer drought (∼20 d) delayed maturity and reduced rice yields by approximately 60-80%. The dry-down approach could help suppress weeds similar to S. mucronatus in organic rice where premium prices can compensate for lower grain yield.  相似文献   

18.
全球变暖背景下,亚热带地区极端气候热浪事件发生频率持续增加。高频热浪及其伴随的高温和干旱复合胁迫将严重影响植物的光合特性,抑制植物的生长,甚至造成死亡。然而,目前亚热带树木光合特性及生长对高频热浪及复合胁迫的响应仍不明确。以亚热带阔叶树种闽楠苗木为研究对象进行了热浪模拟实验,关注了补水和控水处理不同水分环境下连续热浪对闽楠光合特性及生长速率的影响。结果表明,补水处理下闽楠净光合速率(Pn)在单次热浪影响下显著下降了34%,同时水分利用效率显著(WUE)下降,但蒸腾速率(Tr)、气孔导度(Gs)和叶片水汽压亏缺(Leafvpd)显著上升(P<0.05)。表明水分充沛的高温环境中闽楠可通过增加蒸腾耗水加速水分蒸散来调节叶片的温度,增强植株光合特性对热浪的抗性。而控水处理下单次热浪处理组Tr和Gs未显著上升,以及Tr与Leafvpd在干湿环境下线性拟合的不同斜率,说明水分胁迫会降低叶片降温的效率,加剧热浪对闽楠光合特性的影响。水分和高温的复合胁迫还延长了闽楠光合特性在热浪后的恢复过程,高温胁迫下闽楠Pn在15 d后恢复至未干扰水平,但复合胁迫...  相似文献   

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