【作者】 明奕；

【导师】 孔凡娜；

【作者基本信息】 中国海洋大学 ， 生物工程， 2011， 硕士

【摘要】 高等沉水植物大叶藻（Zostera marina L.）是广泛分布于我国辽宁、山东及河北沿海浅海水域中的一种海草,具有重要的生态学价值。大叶藻能够在高盐度海水中完成整个生活史,是研究高等植物耐盐机理的良好材料。本研究对青岛浅近岸海域汇泉湾大叶藻的生物量进行野外追踪调查,分析其月变化特征,揭示大叶藻生物量分配的季节规律;采用解剖学方法探究不同盐度对大叶藻形态结构的影响;采用生理学方法研究不同盐度海水对大叶藻的生理效应,探讨大叶藻耐盐的生理机制。1.青岛汇泉湾大叶藻的生物量月动态特征于2010-2011年对青岛汇泉湾大叶藻生物量进行野外跟踪调查,结果表明,2010年5月-2011年4月,生物量的月变化经历了一个由减少到增加的过程。5月份生物量达到最大值。6月-10月是大叶藻种群特征变化最大的时期,平均株高明显下降,种群密度迅速减少,生物量出现明显下降,生物量积累速率为负值。11月份以后生物量出现小幅增加,生物量积累效率较低。初春进人快速生长期,植株高度增加,种群密度增加,生物量大量积累,生物量积累效率较高。11月-次年4月群落AGR（绝对生长速率）值为正;5-10月AGR值为负。大叶藻在11月到次年4月RGR（相对生长速率）值为正,而5-10月份RGR均为负值。2.大叶藻解剖结构的观察显微结构和超微结构观察结果显示,根表皮最外层有一层体积较大的破碎的薄壁细胞;紧接着是一层小而紧密的细胞,根的中心是维管束,表皮和维管束之间有巨大的气道。盐度对大叶藻通气组织的形成有一定影响。茎表皮是由一层小而排列紧密的细胞构成的。茎的中心是中央维管束,中央维管束和表皮之间是薄壁组织,其间规则的散布气道。不同盐度下幼苗茎部结构并没有太大差别,但52.5盐度人工海水处理的大叶藻茎外围有一层增生组织,其中分布着巨大的气道。幼苗大叶藻的茎表皮为功能细胞,推测幼茎也具有一定的吸收功能。大叶藻叶仅有一层小而致密的表皮细胞,叶肉细胞为大型薄壁组织;叶片内散布着排列十分规则的巨大气道及叶片维管束,气道是由薄壁细胞规律排列而成的花环状结构,隔4个左右的气道就有由薄壁细胞和厚角细胞紧密排列组成的叶片维管束。大叶藻叶表皮细胞壁增厚有随盐度增加而增加的趋势。正常海水盐度处理的大叶藻叶绿体结构最为完整,其受低渗影响和高渗影响都比较大。17.5及35盐度处理下叶中线粒体保持完整,52.5盐浓度可使叶中的线粒体嵴膨胀,结构破坏。3.大叶藻对盐胁迫的生理响应在实验室条件下,测定大叶藻的耐盐阈值,研究了不同盐度海水处理（17.5,35,52.5）对大叶藻的生理效应。结果表明,大叶藻存活的耐盐阈值为61.25;呼吸速率随着盐度的增加呈不显著增加趋势,光合速率随着盐度增加而略有降低;大叶藻叶片中Na⁺、Ca²⁺含量、渗透势、丙二醛含量、脯氨酸含量、自由氨基酸、可溶性糖和有机酸均随着海水盐度的增高而显著增加;K⁺含量随海水盐度的增高而降低;海水浓度变化对大叶藻含水量影响不大;Na⁺的含量为叶>根>茎,说明大部分Na⁺储存在叶片中;随着盐处理浓度的增加大叶藻植株的K⁺/Na⁺比和Ca²⁺/Na⁺比值均明显降低,盐度梯度下大叶藻根部、茎部及叶部对SK,Na （ASK, Na）的吸收呈显著上升趋势。而ASCa,Na值呈缓慢增加的趋势,差异不显著。更多还原

【Abstract】 Zostera marina L. is a kind of seagrasses that widely distribute in the sea of Liaoning Province, Shandong Province and Hebei Province. Z. marina can complete the entire life history in the high salinity of sea water, so it is considered as the perfect material to study the mechanism of salt tolerance in higher plants. In this paper, the biomass of Z. marina in Qingdao Huiquan bay was investigated to reveal the seasonal allocation rules of the Z. marina. Furthermore, the effect on the anatomical structures of Z. marina and the physiological effects of Z. marina in different salinity were studied to discuss the physiological mechanisms of salt-tolerance of Z. marina.1. The monthly dynamic characteristics of biomass of Z. marina in Qingdao Huiquan bayThe continuous investigation of biomass of the Z. marina L in Qingdao Huiquan bay has been proposed from 2010 to 2011. The analysis of the monthly variation date showed that the biomass underwent a process of reduction to an increase from May to April and the maximum of biomass appeared in May. The population characteristics has changed obviously from June to October,with the average height decreasing significantly and the population density declining rapidly. Furthermore the biomass has declined markedly and accumulation rate of biomass is negative. After November the biomass has a slight increased, biomass accumulated less efficient. The biomass entered the fast growing period in the early of spring.The plant height and the population density has increased. The biomass accumulated rapidly. The community AGR （absolute growth rate） is positive from November to April of next year; and the AGR is negative from May to October. The RGR （relative growth rate） of Z. marinaL in May to October are negative, while November to April of next year the value of RGR is positive.2. The observation of the anatomical structures of Z. marina The observation of frozen section and scanning electron microscope from Z. marina in different salinity （17.5, 35, 52.5） artificial seawater （ASW） showed that the outermost of the root epidermis is larger parenchyma cells which structure is broken. Next to the broken larger parenchyma cells is small sclerenchymatous cell which arranged closely. The center of the root is vascular bundle. There are many large aerenchymas between the epidermis and vascular bundle in root. The salinity treatment affects the formation of the aerenchyma to some extent. The outermost broken parenchyma cells are presumed that it only existing in seedlings of Z.marina, and its functions need to be studied further. The epidermis of shoot of Z. marina is a layer of small cells which closely arranged. The center of the shoot is vascular bundle, between the vascular bundle and epidermal there is parenchyma, which was distributed many aerenchymas. The scanning electron microscope of the shoot of Z. marina in 52.5‰ASW treated show that there is some hyperplasia surrounded by the shoot in which distributed large aerenchyma, and the structure of the hyperplasia are very similar to leaves. There are functional epidermal cells in shoot, suggesting that young shoot also has some absorption function. There is only a layer of small and dense epidermal cells of the leaf. The mesophyll consisted of many large parenchyma cells. There are a lot of large aerenchymas and some leaf vein in the leaf. The aerenchyma of the leaf is constituted of the regular arrangement parenchyma cells which look like a flowers ring. About every four aerenchyma there is a leaf vein which is constructed by parenchyma cells and collenchyma cells. The leaf epidermal cell wall is thickening with salinity increasing. The chloroplast structure is most complete in normal sea water salinity. It was worse impacted by hypotonic and hypertonic. The certain salinity can lead in the mitochondria’s structural damage.3. The physiological response of Z. marina to salt stress Under laboratory conditions the limiting salinity of Z. marina was measured. Thephysiological effects in different salinity gradients （17.5, 35, 52.5） were identified and the physiological mechanisms of sea halophyte were discussed. The results showed that the limiting salinity of Z. marina was 61.25. The respiration rate of Z. marina L has increased and the photosynthetic rate has decreased slightly with the increasing salinity. The content of Na⁺, Ca²⁺, organic osmoticas, such as proline, free amino acids, organic acids, soluble sugars, MDA increased with increasing salinity. The osmotic potential also increased with increasing salinity. However, the contents of K ⁺ were decreased with increasing salinity and water content was no significant difference under salinity gradients treatment. The content of Na⁺ is leaf> root> stem, and the K ⁺ / Na ⁺ ratio and Ca^{2 +} / Na ⁺ ratios were significantly lower. The ASK, Na of shoot, stems and leaves was gradually increased, but the increasing of ASCa, Na was not significant更多还原