【作者】 廖宝文；

【导师】 徐大平；

【作者基本信息】 中国林业科学研究院 ， 森林培育， 2010， 博士

【摘要】 由于长期不合理的开发和乱砍滥伐,我国红树林面积急剧减少,林分质量和防护效能不断下降。为了促进红树林恢复与发展,亟需加强红树林人工营造工作。而大量造林实践表明,淹水时间和海水盐度是红树林造林成功与否的主要限制因子。开展红树植物对淹水时间及对盐度耐受程度的研究,将为今后的红树林造林的立地选择提供理论依据和技术支撑。本研究于2005-2009年,建立室内潮汐模拟湿地系统,以红树林常见造林树种尖瓣海莲（Bruguiera sexangula（Lour.） Poir. var. rhynchopetala Ko）、秋茄（Kandelia candel （L.） Druce）和白骨壤（Avicennia marina Vierh）为研究对象,人工控制不同淹水时间(即2、4、6、8、10、12、14、16、18、20、22、24 h·d^-1)和水体盐度（即0、5、10、15、20、25、30、35、40‰）,通过分析比较幼苗生长与生理生化指标、矿质元素含量等的变化,对比分析3种红树植物对潮水淹浸与盐度的适应能力。主要研究结果如下:（1）尖瓣海莲幼苗在淹浸时间超过14 h·d^-1后尖瓣海莲幼苗部分死亡,超过16 h·d^-1后其胚轴发芽率下降,淹浸24 h·d^-1苗木全部死亡;随淹浸时间的延长,叶片叶绿素含量、根系活力和硝酸还原酶活性先升后降,而游离脯氨酸含量、丙二醛含量和相对电导率则先降后升,并在12 h·d^-1处出现骤变分界点。尖瓣海莲的单株总生物量在淹浸6 h·d^-1处理下最大,当淹浸时间超过12 h·d^-1后,总生物量骤降。综合分析各项指标后得出:在水体盐度为10的处理下,尖瓣海莲幼苗的最适淹浸时间为6～8 h·d^-1,临界淹浸值为12 h·d^-1。（2）淹水逆境对秋茄幼苗生长有显著影响,具体表现如下:秋茄幼苗的总生物量、茎及根干重均在淹浸12 h·d^-1的处理最大,当淹水超过16 h·d^-1后,秋茄幼苗总生物量骤降;淹水逆境对秋茄幼苗叶片的月均增长量影响最大,淹水2 h·d^-1的比淹水24 h·d^-1的增加了80%;随淹浸时间的延长,秋茄幼苗的叶绿素含量、过氧化物酶活性和根系活力先升后降,而SOD、游离脯氨酸、丙二醛和相对电导率则先降后升,并在淹水16 h·d^-1处理下出现骤变分界点。综合分析以上指标,结合适应度分析得出:在水体盐度为10的处理下,秋茄幼苗的最适淹水时间为8～12 h·d^-1,临界值为16 h·d^-1。（3）随淹水时间的延长,白骨壤幼苗的月均苗高、地茎及叶片数增量均呈先増后减趋势,在8～12 h·d^-1的淹水处理下保持较高数值,淹水时间≥16 h·d^-1后,生长变弱;随着淹水时间的延长,苗木生物量先増后减,在10 h·d^-1的淹水处理下值最大,当淹水时间≥16 h·d^-1后,生物量显著下降;通过对不同时间淹水处理下白骨壤小苗的单株叶干重、单株茎干重、单株根干重、总生物量、月均苗高增量、月均地茎增量、叶面积、净光合速率、叶绿素总量和根活力等10项生长信息指标的主成分分析,在水体盐度为10的处理下,白骨壤苗在淹水<16 h·d^-1下均能正常生长,在淹水8～12h·d^-1下较适宜生长,当淹水时间超过16 h·d^-1后生长受到明显抑制,即临界值为16h·d^-1。（4）水体盐度梯度对尖瓣海莲苗影响的实验表明,随着盐度的升高,尖瓣海莲幼苗叶片内的SOD活性、游离脯氨酸含量、丙二醛含量及质膜透性均呈先减小后增大趋势;幼苗的生长量、各器官生物量及总生物量均呈现“高抑低促”的现象;盐度为5的处理下,幼苗生长最旺盛,盐度超过25后生长受抑制,盐度为5的总生物量比盐度为40的大25倍;主成分综合分析表明,尖瓣海莲幼苗适合生长的盐度为25以下,盐度5最适生长,当盐度超过25后,生长明显受抑。（5）水体盐度梯度对秋茄的实验表明,随着盐度的升高,秋茄幼苗的叶片SOD活性、游离脯氨酸含量、丙二醛含量及质膜透性均不断增大;秋茄幼苗的生长量、生物量、净光合速率、根系活力、叶片叶绿素含量均以盐度为5的处理最大,盐度高于10后,则随着盐度的升高而数值下降。秋茄幼苗的最适生长盐度为5,在盐度10～30处理下,随着盐度的升高,秋茄幼苗生长逐渐减慢;在淡水和盐度30的处理下,秋茄幼苗生长明显受抑。（6）以尖瓣海莲幼苗为对象,研究了不同淹水时间(4、8和12 h·d^-1)和不同水体盐度（5、15、25）的组合下的交互作用。结果表明,淹水与盐度各自对尖瓣海莲幼苗的绝大多数生长指标（叶片数除外）均有显著影响,但两者的交互作用不显著,仅对叶片宽度有显著影响。10项生长信息指标的主成分分析结果表明:在淹水4～8h h·d^-1和盐度5～15的组合处理下,较适合尖瓣海莲幼苗生长。（7）以秋茄幼苗为对象,研究了淹水时间(4、8和12 h·d^-1 )与水体盐度（5、15、25）组合下的交互作用。结果表明,淹水与盐度对秋茄幼苗的绝大多数生长指标均有不同程度的影响,但两者的交互作用影响不显著,仅对主根条数有显著作用。主成分分析结果显示:在淹水12h.d^-1与盐度5的组合处理下,秋茄苗生长最好。（8）测定了以上实验幼苗的元素含量,包括N、P、K、Ca、Cl、Mg、Na、Al、Fe、Mn、B等,结果表明:淹水和盐度对尖瓣海莲、秋茄和白骨壤幼苗各器官矿质元素均有影响,其中以叶片的元素含量变化最明显。在淹水试验中,秋茄幼苗叶片内元素Ca、Cl、Na、Fe、B含量随淹水时间的延长而显著上升,K却是较有规律的随着淹水时间的延长而减少,Al、Zn和Cu元素随淹水时间的延长呈现先降低再上升的趋势。尖瓣海莲幼苗叶片中元素N、Mg、Al、P和Fe含量随着淹水时间的延长而上升,且Mg、Al和Fe含量在淹水时间超过12h.d^-1后明显上升。白骨壤小苗叶片中P、Ca、Al、Fe、Mn、Ni和B元素均为有规律的随着淹浸时间的延长而上升,元素K较有规律的随着淹水时间的延长而减少,Zn含量随淹水时间的延长先升后降。在潮水盐度实验中,秋茄幼苗叶片中元素Na、Cl和Cu随盐度梯度增加呈增长,但元素K、Ca、Mg和Zn随着盐度的增加而减少;根部的P、Na、Cl、Fe和Mn随盐度增大而增大,但元素K和Ca随着盐度的增加而减少。（9）从植株矿质元素的分析结果可知:秋茄、尖瓣海莲和白骨壤幼苗在长时间的淹水胁迫下,植株缺氧处于还原状态使一些离子的溶解度降低,导致Fe、Al等金属元素的含量过高而逐渐中毒,可能是造成这3种红树植物幼苗在长时间淹水胁迫下生长不良或死亡的主要原因。秋茄幼苗在高盐度胁迫下体内Na、Cl含量过高和K、Ca、Mg、Zn含量的下降影响了幼苗的生理平衡,引起幼苗根部的Fe、Mn等金属离子毒害的产生,可能是秋茄幼苗在过高盐度胁迫下生长不良或死亡的主要原因。更多还原

【Abstract】 Due to the long time deforestation, mangrove forest area in China dropped sharply, and forest quality and protective efficacy has been declined. In order to promote mangrove rehabilitation and sustainable development, strengthening the work of artificial mangrove reforestaion was urgent. Lots of forest practices showed that the tide-flooding time and salinity are the major limiting factor for mangrove forestation success. Therefore, Carrying out the study on adaption and tolerance of mangrove to tide-flooding and water salinity would provide theoretical basis and technical support to mangrove restoration. In this study, indoor tide simulated wetland system was establishment from 2005 to 2009, and the common mangrove species Bruguiera sexangula, Kandelia candel and Avicennia marina were the studied. Manual controlled the tide-flooding time was twelve gradients (2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24 h.d^-1) and the water salinity was eight gradients （0, 5, 10, 15, 20, 25, 30, 35, 40‰）. Through analyzing and comparing the growth indexes, physiological indexes and mineral elements of mangrove seedlings, the adaptability of mangrove species to tide-flooding and water salinity was studied. The major results are as follow:（1） B. sexangula seedlings died partly when the tide-flooding time was more than14 h·d^-1,and hypocotyl germination rate decreased when the tide-flooding time was more than16 h·d^-1, but seedlings all died when the tide-flooding time was 24h·d^-1. As increasing of the tide-flooding time, chlorophyll, root activity and nitrate reductase activity increased fist and then decreased, but free proline, malonaldehyde and relative conductivity decreased first and then increased. The physiological indexes changed suddenly at the tide-flooding treatment of 12h·d^-1. The largest total biomass was occurred at the treatment of 6h·d^-1, and total biomass decreased suddenly when the tide-flooding time was more than12 h·d^-1. Comprehensive analysis of indicators shows that the optimal flooding time of B. sexangula is 6⁸h.d^-1, and the critical flooding time is 12h.d^-1 in the water salinity treatment of 10‰.（2） Water-logging stress has a significant effect on the growth of K. candel seedlings, specific performance is as follows: total biomass, stem dry weight, root dry weight are highest at the treatment of 12h·d^-1, and total biomass decreased suddenly when the tide-flooding time was more than 16h·d^-1. Water-logging stress has greatest impact on the leaf increment per month of the K. candel seedlings, and the leaf increment per month with the treatment of 2h·d^-1 is 0.8 times more than the value with the treatment of 24h·d^-1. As increasing of the tide-flooding time, chlorophyll, nitrate reductase activity and root activity increased fist and then decreased, but SOD, free proline, malonaldehyde and relative conductivity decreased first and then increased. The physiological indexes changed suddenly at the tide-flooding treatment of 16h·d^-1. Comprehensive analysis of indicators shows that the optimal flooding time of K. candel is 8¹2h.d^-1, and the critical flooding time is 16h.d^-1 in the water salinity treatment of 10‰.（3） As increasing of the tide-flooding time, the height increment, stem increment and leaf increment per month of A. marina seedlings all increased fist and than decreased. The values of growth keep high at the treatment of 8¹2 h.d^-1, and grow changed bad when the tide-flooding time was more than 16 h.d^-1. As increasing of the tide-flooding time, biomass of A. marina seedlings increased fist and than decreased, the largest value is at the treatment of 10h.d^-1, and biomass decreased significantly when the tide-flooding time was more than 16h.d^-1. Principal component analysis of ten growth information indexes including leaf dry weight, stem dry weight, root dry weight, total biomass, height increment per month, stem increment per month, leaf area, net photosynthesis rate, chlorophyll and root activity shows that A. marina seedlings grows normally when the tide-flooding time was less than 16 h.d^-1, the optimal flooding time is 8¹2h.d^-1, and the critical flooding time is 16 h.d^-1 in the water salinity treatment of 10‰.（4）The water salinity experiment of B. sexangula seedlings indicated that SOD, free proline, malonaldehyde and membrane permeability decreased first and than increased with rising of salinity. The growth, biomass of every organs and total biomass of seedlings are promoted with the low salinity treatment, and are inhibited with the high salt treatment. B. sexangula seedlings grow best at the salinity treatment of 5‰, and growth inhibited when the treatment salinity was more than 25‰. The maximum value of total biomass is 25 times more than the minimum value. Principal component synthesized analysis shows that B. sexangula seedlings can grow normally with the treatment salinity less than 25‰, and grows best with the treatment salinity of 5‰, but the growth inhibited obviously when the treatment salinity was more than 25‰.（5） The water salinity experiment of K. candel seedlings indicated that SOD, free proline, malonaldehyde and membrane permeability increased constantly with rising of salinity. The maximum value of growth, biomass, net photosynthesis rate, root activity and chlorophyll are all at the salinity treatment of 5‰, and decreased as increasing of salinity when the treatment salinity was more than 10‰. The optimum salinity to K. candel seedlings is 5‰, and the growth slow down gradually as increasing of salinity when the treatment salinity was 10 to 30‰. The growth of K. candel seedlings inhibited obviously when the salinity was 0 or 30.（6） Interaction of different flooding time and water salinity on B. sexangula seedlings was studied. Dealt the flooding time with three gradients of 4, 8, 12 h.d^-1and water salinity with three gradients of 5, 15, 20‰. The result shows that flooding time and water salinity have significant effect at the most of the growth indexes excepting leaf number, but their interaction is not significant excepting leaf width. Principal component analysis of ten growth information indexes with the interaction of different flooding time and water salinity shows that the optimum treatment combination is flooding with 4 to 8 h.d^-1and salting with 5-15‰.（7） Interaction of different flooding time and water salinity on K. candel seedlings was studied. Dealt the flooding time with three gradients of 4, 8, 12 h.d^-1and water salinity with three gradients of 5, 15, 20‰. The result shows that flooding time and water salinity have varying degrees effect at the most of the growth indexes. The impact of salinity is greater than flooding time. Principal component analysis of ten growth information indexes with the interaction of different flooding time and water salinity shows that the optimum treatment combination is flooding with 12h.d^-1and salting with 5‰.（8） Mineral elements which including N, P, K, Ca, Cl, Mg, Na, Al, Fe, Mn and B of experiment seedlings were measured. The result shows that flooding time and water salinity all have effect on the organs of B. sexangula, K. candel and A. marina seedlings. Leaf elements changed most obviously. In the flooding experiment, as rising of the flooding time, Ca, Cl, Na, Fe and B in the leaf of K. candel seedlings increased obviously, and K contend decreased, but Al, Zn, Cu decreased first and then increased. N, Mg, Al, P and Fe contend in the leaf of B. sexangula seedlings increased, and Mg, Al and Fe increased obviously when the flooding time was more than 12h.d^-1. P, Ca, Al, Fe, Mn, Ni and B in the leaf of A. marina seedlings increased, but K contend decreased, and Zn increased first and then decreased. In the water salinity experiment of K. candel seedling, as rising of the water salinity, Na, Cl, and Cu in the leaf increased, K, Ca, Mg and Zn decreased, P, Na, Cl, Fe and Mn in the root increased, but K and Ca decreased.（9） Analysis of mineral element shows that, the long-time flooding lead B. sexangula, K. candel and A. marina seedlings to plant hypoxia. Plant hypoxia cause some ion in a state of lower solubility, and this can result in accumulation of metal elements such as Fe, Al and so on. Excessive accumulation of mental elements can cause poisoning. This may be the major factor cause the die of three mangrove species in the long-time flooding. Excessive accumulation Na, Cl and lower contend of K, Ca, Mg, Zn of K. candel seedlings in the high-salinity treatments can affect physiological balance, and this will cause metal poisoning such as Fe, Mn poisoning. This may be the major reason of poor growth of K. candel seedlings in the high-salinity treatments.更多还原