【作者】 方煜；

【导师】 郑文教；

【作者基本信息】 厦门大学 ， 植物学， 2008， 硕士

【摘要】 采用砂基栽培,研究重金属Cr（Ⅲ）在不同浓度梯度和不同胁迫处理阶段（种苗期和幼苗期）及胁迫处理时间条件下对红树植物白骨壤（Avicenniamarina）幼苗的生长及生理生态效应的影响。设置Cr（Ⅲ）胁迫浓度系列为100、200、300、400、500、600、800 mg·L^-1,以不加Cr（Ⅲ）为对照,培养基海水盐度均为15‰,培养期分为45d和150d。实验期间全程记录及观测各胁迫组白骨壤种苗萌发及幼苗生长状况,定期记录幼苗的高度生长、叶片大小,并分别在胁迫栽培45d和150d采样测定幼苗根系生长、各组分生物量生长,以及幼苗含水量、叶绿素含量、可溶性蛋白含量、抗氧化酶活性、膜脂过氧化作用、盐分代谢、Cr的累积分布等指标参数。研究结果表明:1.种苗期进行Cr（Ⅲ）胁迫处理25d,白骨壤种苗初期萌发率没有受到明显的影响;随着胁迫时间的延长和胁迫强度的提高,白骨壤幼苗幼叶萌生和幼苗成活率均受到抑制。2.种苗期进行Cr（Ⅲ）胁迫处理（45d或150d）对白骨壤幼苗根数影响不大,但对根长、苗高、叶片大小、生物量均有不利影响。3.种苗期进行Cr（Ⅲ）胁迫（45d或150d）对幼苗各组分含水量均有一定的影响,其中对叶片含水量有较明显的降低作用。4.种苗期进行Cr（Ⅲ）胁迫处理45d或150d,对白骨壤幼苗叶片叶绿素含量有一定的促进作用;幼苗期进行胁迫处理45d对叶片叶绿素含量则有抑制作用。5.种苗期进行Cr（Ⅲ）胁迫处理（45d或150d）,对白骨壤幼苗根尖和叶片可溶性蛋白质含量有促进作用;幼苗期胁迫45d,根尖可溶性蛋白含量变化不显著,叶片可溶性蛋白含量则随Cr（Ⅲ）浓度的提高而提高,但提高幅度小于种苗期。6.种苗期进行Cr（Ⅲ）胁迫45d,随着生长基Cr（Ⅲ）浓度的提高,白骨壤幼苗根尖和叶片SOD活性均表现为随之逐渐上升,胁迫时间延长达150d时各胁迫组根尖SOD活性均低于对照组,叶片SOD活性则先下降后上升;幼苗期进行Cr（Ⅲ）胁迫45d,随着Cr浓度的提高根尖SOD活性缓慢升高,叶片SOD活性表现为中低浓度下影响不大,高浓度(＞600 mg·L^-1)则明显下降。7.种苗期进行Cr（Ⅲ）胁迫处理（45d或150d）,对白骨壤幼苗根尖和叶片POD活性均有明显的促进作用;幼苗期胁迫45d,各组根尖POD活性均显著下降,叶片POD活性则随培养基Cr（Ⅲ）浓度的增加而逐渐提高,但提高幅度较种苗期小。8.种苗期进行Cr（Ⅲ）胁迫处理（45d或150d）,对白骨壤幼苗根尖CAT活性有促进作用,而对叶片CAT活性则起一定的抑制作用;幼苗期进行Cr（Ⅲ）胁迫栽培45d,各胁迫组幼苗根尖CAT活性变化不大,叶片CAT活性在100mg·L^-1Cr（Ⅲ）浓度下达到最大,而后随着生长基Cr（Ⅲ）浓度的增加而下降,但下降幅度小于种苗期。9.种苗期进行Cr（Ⅲ）胁迫处理（45d或150d）白骨壤幼苗根尖和叶片AsA含量均有明显的促进作用;幼苗期进行胁迫处理45d,白骨壤幼苗根尖AsA含量均低于对照,叶片AsA含量则没有明显变化。10.Cr（Ⅲ）胁迫对白骨壤幼苗根尖和叶片膜脂过氧化作用没有明显负效应。11.种苗期进行Cr（Ⅲ）胁迫处理45d,重金属Cr（Ⅲ）对白骨壤幼苗原胚轴、茎、叶片中Cl的累积有负效应,而对根系而言则表现出“低促高抑”的规律,当胁迫时间延长到150d时,白骨壤幼苗各组分Cl含量均表现为先升高后降低的趋势;幼苗期进行Cr（Ⅲ）胁迫处理45d对各组分对Cl的吸收没有明显影响。12.白骨壤幼苗各组分对Cr的吸收均表现出先升后降的趋势。白骨壤幼苗根系对培养基Cr的富集系数最大,即根系表现为Cr的最大累积器官。13.随着Cr（Ⅲ）胁迫强度的提高,白骨壤幼苗叶片的泌盐速率逐渐提高。更多还原

【Abstract】 In this paper,mangrove Avicennia marina hypocotyls were cultivated in sand with 15‰seawater.Some were treated with Cr（Ⅲ） once planted,and some were treated when growing 6 months.The influence of increasing concentrations of Cr （Ⅲ）(0,100,200,300,400,500,600,800 mg·L^-1) on hypocotyls germination and growth,photosynethesis metabolism,water metabolism,salt contents and membrance protection system were observed to inquire into the ecophysiological responses of mangrove A.gymnorrhiza to Cr phytotoxicity.The results showed:1.The germination of A.marina seedlings was not obviously influenced by Cr （Ⅲ） pollution during the early germination period.But with the stress time extending and the stress concentrations increasing,the shooting rate and the survival rate were restrained.2.The number of roots was not influenced remarkable by Cr（Ⅲ） whenever stressed 45 days or 150 days,and there were negative effects on the length of roots, the height of stems,the size of leaves and the biomass.3.When hypocotyls were stressed（45 days or 150 days）,Cr（Ⅲ） had effect on the water content of some parts,especially that of leaves dropped obviously.4.When hypocotyls were stressed 45 days or 150 days,the contents of chlorophyll a,chlorophyll b,and total chlorophyll of leaves were higher than CK; Treated 45 days when seedlings growthing 6 months,the contents were below CK remarkably.5.The content of soluble protein in roots and leaves were above CK whenever 45 days or 150 days hypocotyls treated;Stressed 45 days when seedlings growthing 6 months,the content of leaves climbed with the increasing of Cr（Ⅲ） concentration, and that in roots was changed unconspicuously.6.When hypocotyls were stressed 45 days,the SOD activity of roots and leaves all presented rose,when stress time reached 150 days,the SOD activity of roots was below CK,but that of leaves showed the dropped first and then rosing;Stressed 45 days when seedlings growthing 6 months,SOD in roots rose slowly,and the activity in leaves decreased above 600 mg·L^-1Cr（Ⅲ）.7.When hypocotyls were stressed（45 days or 150 days）,the POD activity of roots and leaves all rising with the Cr（Ⅲ） concentration increasing;Stressed 45 days when seedlings growthing 6 months,the activity of roots was decreasing gradually and that of leaves was opposite.8.When hypocotyls were stressed（45 days or 150 days）,the CAT activity of roots rose but the activity of leaves was decreasing with the Cr（Ⅲ） concentration increasing;Stressed 45 days when seedlings growthing 6 months,the change of CAT of roots was not clear,and CAT activity in leaves reached the peak at 100mg·L^-1Cr （Ⅲ） concentration,and then dropped.9.The content of AsA in roots and leaves was rising whenever stressed 45 days or 150 days;Stressed 45 days when seedlings growthing 6 months,the content of AsA in roots was lower than CK,but the content of AsA in leaves was not influenced obviously.10.The effect of Cr（Ⅲ） on the MDA concentration in the roots and leaves was not abvious.11.When hypocotyls were stressed 45 days,the C1 contents of hypocotyls,stems and leaves were decreased with increasing Cr（Ⅲ） concentrations,otherwise the C1 content of roots rose first and then dropped,with the stress time prolonged to 150 days,the C1 contents of each part all rose first and then dropped;Stressed 45 days when seedlings growthing 6 months,the contents were not changed obviously.12.The tendency of Cr absorption in each parts of A.marina seedlings rose first and then dropped,and the content of Cr in roots was the highest.13.The rate of excreting salt on leaves was increasing with the Cr（Ⅲ） concentration rising.更多还原