IOCAS-IR  > 海洋生态与环境科学重点实验室
山东沿海典型海草床鳗草种子生态学研究
徐少春
学位类型硕士
导师周毅
2017
学位授予单位中国科学院大学
学位授予地点北京
学位专业环境工程
摘要鳗草(Zostera marina L.),又名大叶藻,广布于北半球温带浅海海域,其中荣成天鹅湖和青岛汇泉湾两地鳗草种群是我国北方沿海鳗草自然种群的典型代表。本文以天鹅湖和汇泉湾两个地理区域的鳗草种子生活史特征为研究重点,分析两个区域鳗草种群种子生活史差异,并结合室内实验研究温度和盐度对鳗草种子萌发、幼苗建成及生长的影响,初步研究了鳗草种子生态学,研究结果对鳗草的保护和恢复具有指导意义。主要结果如下:
1. 天鹅湖和汇泉湾两个海域的鳗草种群有性生殖努力(Reproductive effort)存在差异。汇泉湾种群开花出现在4月中旬,较天鹅湖种群早半个月;两个种群生殖枝密度均在6月份达到最大值(天鹅湖517.27±504.29 茎枝/m2,汇泉湾203.04±116.50茎枝/m2);7月底生殖枝迅速衰败,8月初生殖枝完全消失。汇泉湾种群每个生殖枝的佛焰苞数(21.5±5.32 个/茎枝)显著高于天鹅湖种群(10.83±3.31 个/茎枝),而天鹅湖种群每个佛焰苞的种子数(9.57±3.44 粒/个)显著高于汇泉湾种群(7.98±3.73粒/个)。天鹅湖种群每平方米的种子产量(53623.66±19628.11粒/m2)显著高于汇泉湾种群(29000.88±10657.89粒/m2)。此外,还发现汇泉湾种群种子的重量和几何大小(长度、直径和体积)显著高于天鹅湖种群。两个种群的种子库大小从7月开始逐渐增大,在10月达到峰值(天鹅湖386.55±247.19粒/m2,汇泉湾254.35±613.34粒/m2),随后种子库大小逐渐降低。
2. 天鹅湖种群种子的萌发集中在春季,而汇泉湾种群种子主要在秋季萌发。随着种子的萌发,天鹅湖种群幼苗的密度最大值出现在4月(377.60±260.09苗/m2),种子的萌发率高达68.38%。幼苗从5月开始进行克隆生长,每个幼苗的茎枝数在5月和6月分别为1.16±0.41茎枝/苗和1.57±0.53茎枝/苗。在6月幼苗密度和幼苗茎枝密度分别为156.25±71.32苗/m2和245.54±112.07茎枝/m2,因此幼苗存活率为41.38%。汇泉湾种群种子的萌发集中在10月和11月,幼苗的密度低于10苗/m2。幼苗从3月底开始进行克隆生长,至6月底每个幼苗茎枝数约2茎枝/苗。采用固定样方方法跟踪调查汇泉湾种群幼苗生长动态,从3月23日到6月26日,幼苗高度由12.49cm迅速生长到33.05cm。
3. 种质来源(天鹅湖和汇泉湾)和温度(10℃和15℃)对鳗草种子萌发率(GP)和萌发速率(GR)具有重要影响。研究发现,温度可显著影响两个种群种子的萌发指标(GP和GR),并且两个种群间种子的萌发指标也存在显著差异。在不同温度条件下,汇泉湾种群种子的萌发指标均显著高于天鹅湖种群。
4. 根据鳗草种子颜色(乳白色、青绿色和黑色)可将种子成熟度分为未成熟、中等成熟和成熟三级。经测定和统计发现,不同成熟度的种子之间其湿重和含水率均具有显著性差异。结果表明,随着种子的成熟,种子湿重显著增加,其含水率显著降低。因此,鳗草种子的颜色、湿重和含水率可作为预测种子成熟度的指标。成熟的鳗草种子湿重为12.50±0.04 mg/粒,其含水率为37.41±0.74%。
5. 盐度和温度对鳗草种子的萌发具有重要影响。研究结果表明,温度升高可以显著提高种子的萌发率,而增加盐度会降低种子的萌发率。鳗草种子在淡水中萌发率最高(80.67~88.67%),温度为15℃的淡水条件下,种子萌发率达到最高(88.67±5.77%)。在盐度为30、35和40ppt条件下,种子的萌发率均低于16%,但是当盐度降低至20ppt以下,种子的萌发率急剧升高。因此,在一定温度范围内鳗草种子的萌发率会随着温度升高而增高。在盐度高于10ppt的条件下,15℃和20℃处理组种子的萌发率显著高于5℃处理组。
6. 盐度对鳗草幼苗建成和生长也具有重要影响。研究发现较高盐度处理组(20和30ppt)和较低盐度处理组(0和10ppt)的幼苗在茎枝高度、重量、叶片数和分化等方面存在显著差异。较低盐度处理组种子的萌发率较高,但其幼苗叶片数、幼苗高度和湿重较低。这一结果表明,低盐环境会减缓或抑制幼苗发展,这可能降低幼苗最终存活率。相反,在较高盐度条件下幼苗叶片数、幼苗高度和湿重相对较高,幼苗存活率相对较高。
7. 不同萌发盐度条件下萌发种子的幼苗建成率存在显著差异。在盐度0、1、5和15ppt条件下萌发的种子转移至自然海水(32ppt)中培育,其幼苗建成率分别为10.00±0.00,28.67±1.15,39.33±4.16和90.67±9.02%。在盐度15ppt条件下,幼苗的建成率显著高于其他盐度处理组;当萌芽盐度降低时,幼苗建成率也降低。因此,适当增加萌发盐度可以提高幼苗建成率。
8. 本文对鳗草种子的萌发、幼苗建成和生长的形态学变化进行了观察和阶段划分。将种子的萌发、幼苗建成和生长分成7个阶段,主要包括:成熟种子、种子萌发、子叶伸展、叶片分化、不定根分化、第二真叶出现、子叶萎缩消失。
鳗草(Zostera marina L.),又名大叶藻,广布于北半球温带浅海海域,其中荣成天鹅湖和青岛汇泉湾两地鳗草种群是我国北方沿海鳗草自然种群的典型代表。本文以天鹅湖和汇泉湾两个地理区域的鳗草种子生活史特征为研究重点,分析两个区域鳗草种群种子生活史差异,并结合室内实验研究温度和盐度对鳗草种子萌发、幼苗建成及生长的影响,初步研究了鳗草种子生态学,研究结果对鳗草的保护和恢复具有指导意义。主要结果如下:
1. 天鹅湖和汇泉湾两个海域的鳗草种群有性生殖努力(Reproductive effort)存在差异。汇泉湾种群开花出现在4月中旬,较天鹅湖种群早半个月;两个种群生殖枝密度均在6月份达到最大值(天鹅湖517.27±504.29 茎枝/m2,汇泉湾203.04±116.50茎枝/m2);7月底生殖枝迅速衰败,8月初生殖枝完全消失。汇泉湾种群每个生殖枝的佛焰苞数(21.5±5.32 个/茎枝)显著高于天鹅湖种群(10.83±3.31 个/茎枝),而天鹅湖种群每个佛焰苞的种子数(9.57±3.44 粒/个)显著高于汇泉湾种群(7.98±3.73粒/个)。天鹅湖种群每平方米的种子产量(53623.66±19628.11粒/m2)显著高于汇泉湾种群(29000.88±10657.89粒/m2)。此外,还发现汇泉湾种群种子的重量和几何大小(长度、直径和体积)显著高于天鹅湖种群。两个种群的种子库大小从7月开始逐渐增大,在10月达到峰值(天鹅湖386.55±247.19粒/m2,汇泉湾254.35±613.34粒/m2),随后种子库大小逐渐降低。
2. 天鹅湖种群种子的萌发集中在春季,而汇泉湾种群种子主要在秋季萌发。随着种子的萌发,天鹅湖种群幼苗的密度最大值出现在4月(377.60±260.09苗/m2),种子的萌发率高达68.38%。幼苗从5月开始进行克隆生长,每个幼苗的茎枝数在5月和6月分别为1.16±0.41茎枝/苗和1.57±0.53茎枝/苗。在6月幼苗密度和幼苗茎枝密度分别为156.25±71.32苗/m2和245.54±112.07茎枝/m2,因此幼苗存活率为41.38%。汇泉湾种群种子的萌发集中在10月和11月,幼苗的密度低于10苗/m2。幼苗从3月底开始进行克隆生长,至6月底每个幼苗茎枝数约2茎枝/苗。采用固定样方方法跟踪调查汇泉湾种群幼苗生长动态,从3月23日到6月26日,幼苗高度由12.49cm迅速生长到33.05cm。
3. 种质来源(天鹅湖和汇泉湾)和温度(10℃和15℃)对鳗草种子萌发率(GP)和萌发速率(GR)具有重要影响。研究发现,温度可显著影响两个种群种子的萌发指标(GP和GR),并且两个种群间种子的萌发指标也存在显著差异。在不同温度条件下,汇泉湾种群种子的萌发指标均显著高于天鹅湖种群。
4. 根据鳗草种子颜色(乳白色、青绿色和黑色)可将种子成熟度分为未成熟、中等成熟和成熟三级。经测定和统计发现,不同成熟度的种子之间其湿重和含水率均具有显著性差异。结果表明,随着种子的成熟,种子湿重显著增加,其含水率显著降低。因此,鳗草种子的颜色、湿重和含水率可作为预测种子成熟度的指标。成熟的鳗草种子湿重为12.50±0.04 mg/粒,其含水率为37.41±0.74%。
5. 盐度和温度对鳗草种子的萌发具有重要影响。研究结果表明,温度升高可以显著提高种子的萌发率,而增加盐度会降低种子的萌发率。鳗草种子在淡水中萌发率最高(80.67~88.67%),温度为15℃的淡水条件下,种子萌发率达到最高(88.67±5.77%)。在盐度为30、35和40ppt条件下,种子的萌发率均低于16%,但是当盐度降低至20ppt以下,种子的萌发率急剧升高。因此,在一定温度范围内鳗草种子的萌发率会随着温度升高而增高。在盐度高于10ppt的条件下,15℃和20℃处理组种子的萌发率显著高于5℃处理组。
6. 盐度对鳗草幼苗建成和生长也具有重要影响。研究发现较高盐度处理组(20和30ppt)和较低盐度处理组(0和10ppt)的幼苗在茎枝高度、重量、叶片数和分化等方面存在显著差异。较低盐度处理组种子的萌发率较高,但其幼苗叶片数、幼苗高度和湿重较低。这一结果表明,低盐环境会减缓或抑制幼苗发展,这可能降低幼苗最终存活率。相反,在较高盐度条件下幼苗叶片数、幼苗高度和湿重相对较高,幼苗存活率相对较高。
7. 不同萌发盐度条件下萌发种子的幼苗建成率存在显著差异。在盐度0、1、5和15ppt条件下萌发的种子转移至自然海水(32ppt)中培育,其幼苗建成率分别为10.00±0.00,28.67±1.15,39.33±4.16和90.67±9.02%。在盐度15ppt条件下,幼苗的建成率显著高于其他盐度处理组;当萌芽盐度降低时,幼苗建成率也降低。因此,适当增加萌发盐度可以提高幼苗建成率。
8. 本文对鳗草种子的萌发、幼苗建成和生长的形态学变化进行了观察和阶段划分。将种子的萌发、幼苗建成和生长分成7个阶段,主要包括:成熟种子、种子萌发、子叶伸展、叶片分化、不定根分化、第二真叶出现、子叶萎缩消失。
其他摘要The eelgrass Zostera marina L. is a dominant seagrass species circumglobally distributed in temperate coastal environments in the North Hemisphere. Two sites were selected in Swan Lake (SLL) and Huiquan Bay (HQB) for monitoring based on historical cover and previous studies in Shandong Peninsula. This study was focused on the characteristics of the seed life cycle of Z. marina in the two sites to analyze the difference in the seed life cycle between the two populations. In addition, the influence of salinity and temperature on seed germination, seedling establishment, and seedling growth of eelgrass was studied. In this study, the seed ecology of Z. marina was investigated, and the main results were as followed:
1. The difference in plant reproductive effort between SLL and HQB populations was compared. The flowering shoots in HQB were firstly observed in the middle of April; while in SLL they was firstly observed in the beginning of May, and both peaked in June (SLL: 517.27 ± 504.29 shoots m-2; HQB: 203.04 ± 116.50 shoots m-2). Flowering shoot density decreased in July and disappeared in early August and the potential seed productions were 29000.88 seeds m-2 in SLL and 53623.66 seeds m-2 in HQB, respectively. The number of spathes per flowering shoot was significantly higher in HQB (21.5 ± 5.32 spathes flowering shoot-1) than that in SLL (10.83 ± 3.31 spathes flowering shoot-1). The number of seeds per spathe was significantly higher in SLL (9.57±3.44 seeds spathe-1) than that in HQB (7.98 ± 3.73 seeds spathe -1). The potential seed production in SLL (53623.66 ± 19628.11 seeds m-2) was significantly higher than that in HQB (29000.88 ± 10657.89 seeds m-2). In addition, the values of seed weight and size (length, diameter and volume) in HQB were significantly larger than those in SLL. The seeds in HQB (8.81 ± 0.03 mg) were significantly heavier than those in SLL (5.78 ± 0.34 mg), and the seed length and diameter in HQB were also larger than those in SLL. Eelgrass seed bank increased from July and peaked in SLL and HQB with 386.55 ± 247.19 seeds m-2 and 254.35 ± 613.34 seeds m-2, respectively, Whereas seed banks both in SLL and HQB declined after October.
2. Seed germination was documented in spring in SLL, while that was documented in autumn in HQB. The seeds germination and seedling density increased dramatically and peaked in April with the maximum value 377.60 ± 260.09 seedlings m-2 in SLL, and the seed germination percentage was 68.38%. The seedling began clonal growth in May and the number of shoots per seedling was 1.16 ± 0.41 in May and 1.57 ± 0.53 in June, respectively. The density of seedling and seedling shoots were 156.25±71.32 seedlings m-2 and 245.54 ± 112.07 seedling shoots m-2 in June 2015, thus the seedling survival percentage was 41.38%. For HQB most of seeds were mainly germinated during October and November, and the seedling density in HQB is lower than 10 seedlings m-2. The clone growth of seedlings began on 23 March, and about 2 shoots per seedling occurred at 26 June. The data based on the tracing observation of the permanent quadrats showed the process of seedlings growth in HQB, and the average height of seedlings increased from 12.49 cm (April) to 33.05 cm (June).
3. Seed source (SLL and HQB) and temperature (10 °C and 15 °C) had significant influence on germination percentage (GP) and germination rate (GR). For SLL and HQB, germination percentage (GP) and germination rate (GR) differed significantly at different temperatures; GP and GR also differed significantly between the two populations. The germination percentage (GP) and germination rate (GR) for eelgrass population in HQB were significantly higher than those in SLL at each temperature.
4. Z. marina seeds were classified by seed color (white, cyan, and black), representing various degrees of seed maturity (immature, medium, and advanced maturity, respectively). The wet weight and moisture content of seeds at different degrees of maturity exhibited a significant difference. The wet weight of seeds significantly increased with increasing maturity; in contrast, the moisture content of seeds significantly decreased with increasing maturity. Therefore, moisture content, together with seed color and weight, may be a potential indicator of Z. marina seed maturity. The average wet weight of Z. marina mature seeds selected for germination was 12.50 ± 0.04 mg, and the mean moisture content was 37.41 ± 0.74%.
5. Salinity and temperature significantly influence seed germination. Seed germination percentages (GP) were significantly higher at higher temperatures and GP decreased with increasing salinities. GP (80.67–88.67%) in freshwater were significantly higher than in artificial seawater at high salinities. The highest GP (88.67±5.77%) among all treatments was recorded at 15 °C in freshwater. At higher salinities (30, 35, and 40ppt), GP were below 16%, but increased considerably when salinity decreased below 20ppt. Generally, GP increased considerably with increasing temperature. Above 10ppt, GP at 15 °C and 20 °C were significantly higher than at 5 °C.
6. Salinity significantly influences seedling growth and establishment at 5 °C. The seedling maximum length, weight, number of leaves, and differentiation of Z. marina differed significantly between the lower salinities (0 and 10ppt) and the higher salinities (20 and 30ppt) at 5 °C. In the low salinities (0 and 10ppt), a significantly higher GP was detected; however, these seedlings had a lower number of leaves, shorter seedling length, and lower wet weight. This suggested that Z. marina seedlings exposed to low salinities exhibited slower development that may reduce their eventual survival over longer exposure times than those tested in the present study. In contrast, the seedling survival percentage was greater at higher salinities.
7. Seedling establishment percentages (SEP) for seeds germinated at reduced salinities and transferred to natural seawater were compared, and there were significant difference. The SEP for seeds germinated at 0, 1, 5, and 15ppt at 15 °C and then transferred to natural seawater (32ppt) at 15 °C, were 10.00 ± 0.00, 28.67 ± 1.15, 39.33 ± 4.16, and 90.67 ± 9.02%, respectively. The SEP at 15ppt was significantly higher than the other levels of salinity and seedling establishment decreased with decreasing salinities. Elevated salinity increased seedling establishment at 15 °C.
8. The metamorphosis of Z. marina, at various growth stages during seed germination and seedling establishment, was observed in the seed germination experiment. Seed germination and seedling growth were divided into seven stages. The seven stages included pre-germination, seed germination, cotyledonary elongation, first true leaf differentiation, adventitious root differentiation, second true leaf emergence and cotyledonary wither.
文献类型学位论文
条目标识符http://ir.qdio.ac.cn/handle/337002/136652
专题海洋生态与环境科学重点实验室
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徐少春. 山东沿海典型海草床鳗草种子生态学研究[D]. 北京. 中国科学院大学,2017.
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