碳限制背景下大型海藻光合功能响应的研究

发布时间：2018-06-22 14:50

本文选题：大型海藻 + 光合作用　；参考：《华南理工大学》2016年博士论文

【摘要】：在近海海域,大型海藻作为主要的初级生产者,对海洋生态系统的健康发挥非常重要的作用;同时,大型海藻作为海藻栽培的主要对象,为人们提供巨大的经济价值。大气中CO_2浓度升高及其导致的气候变化对近岸海洋生态系统及大型海藻的影响已受到广泛关注。然而,在现实环境条件下,由于海水中CO_2的供应过缓以及藻体群体密度过大等因素使大型海藻常处在碳限制的状态。目前,关于碳限制及与其它重要环境因素变化的相互作用如何影响大型海藻还知之甚少。本研究以我国南方海域主要栽培海藻种类坛紫菜(Pyropia haitaneisis)和龙须菜(Gracilaria lemaneiformis)、以及常见海藻种类舌状蜈蚣藻(Grateloupia livida)和石莼(Ulva lactuca)为研究对象,探讨碳限制对大型海藻的生长、光合功能及相关重要生理过程的影响。主要研究结果如下:海水中低CO_2供应(20 ppm)抑制坛紫菜和龙须菜的相对生长速率(RGR)、光合系统活性以及NO_3~-的吸收速率,并且低CO_2对龙须菜RGR的抑制作用大于对坛紫菜RGR的抑制作用。在较低的日光强度下(强度为全日光的20%),坛紫菜的RGR、光合性能(光合系统活性和光合速率)以及NO_3~-的吸收速率都增高,但龙须菜的RGR、光合系统和抗氧化酶(超氧化物歧化酶和过氧化氢酶)活性以及NO_3~-的吸收速率均降低。降低海水中CO_2供应和同时降低日光强度能够增加坛紫菜的光合色素含量(叶绿素a,类胡萝卜素,藻红蛋白和藻蓝蛋白),以及藻体利用HCO_3~-和光合系统抵抗短期温度变化的能力。经低CO_2和低光照处理后,龙须菜的叶绿素a、类胡萝卜素、抗氧化酶活性以及光合系统活性均能够在实验室条件下恢复到同一水平。另外,降低和增加海水中CO_2供应(1000 ppm)均降低舌状蜈蚣藻的RGR和光合系统活性,降低CO_2供应却提高藻体的藻红蛋白和藻蓝蛋白含量。在栽培海藻的生长过程中,其生物量密度不断增加。实验结果表明,增加坛紫菜的生长密度能够降低藻体的RGR、光合性能以及氮代谢(NO_3~-的吸收速率和硝酸还原酶活性);在高密度(5 gL~(-1))与低CO_2供应下生长的坛紫菜表现出相似的光合性能;低CO_2供应与同时的高密度条件进一步加剧对坛紫菜光合速率的抑制作用。在自然海区,高密度群体(12g/簇)生长的龙须菜相比于低密度群体(4g/簇)生长的龙须菜具有较低的RGR以及光合速率;随着海藻群体密度的增加,藻体进入深水层(1.5m),而深水层生长的龙须菜光合色素含量以及光合速率明显升高。因此,在龙须菜栽培过程中应平衡生长密度与深度对龙须菜生长和光合的影响,使海藻保持高的光合速率。潮间带不同位置的海藻种群光合作用行为对生物量密度存在差异性的响应。实验结果表明,生长在高潮位(干出时间为4h)和中潮位(干出时间2h)的石莼光合速率随着生物量密度的增大而增大,而生长在低潮位(干出时间为0 h)的石莼光合速率随着生物量密度的增加而降低。在不同的海藻生物量密度条件下,增加海水中HCO_3~-浓度明显地提高石莼的总光合速率(Pg),而增加HCO_3~-浓度不能显著提高坛紫菜的Pg。这表明,石莼群体光合的碳限制程度高于坛紫菜群体的碳限制程度。另外,在一定流速范围内("f3.5 cm s~(-1))增加海水的流速对坛紫菜和石莼的Pg均没有显著的影响。综上可知,降低CO_2供应(碳限制)能够抑制坛紫菜、龙须菜和舌状蜈蚣藻的生长和光合功能以及其它相关生理过程;高生长密度与低的CO_2供应对坛紫菜的光合作用具有相似的抑制作用;高生物量密度抑制龙须菜、坛紫菜和石莼的光合行为;在坛紫菜和石莼的生长期间群体中的藻体光合作用都处于碳限制的状态,且石莼经历的碳限制程度强于坛紫菜。本研究结果将有助于更全面地理解大型海藻与光合作用无机碳供应状态的关系,以及海藻在碳限制等现实环境条件下的生理生态功能;同时,本研究紧密联系海藻栽培实践,研究结果为高产、高效的海藻栽培措施与方法提供重要基础理论依据和技术支持。
[Abstract]:In offshore waters, large algae, as the main primary producers, play a very important role in the health of marine ecosystems. At the same time, large algae, as the main object of marine algae cultivation, provide great economic value for people. The increase of CO_2 concentration in the atmosphere and its resulting climate change to coastal marine ecosystems and large seas. The effects of algae have been widely concerned. However, under the conditions of real environment, the large algae are often in a state of carbon restriction because of the slow supply of CO_2 in sea water and the excessive density of the algae. The study was conducted on the main species of seaweed species (Pyropia haitaneisis) and Gracilaria lemaneiformis (Gracilaria lemaneiformis), and the common seaweed species, Grateloupia livida and Ulva (Ulva Lactuca), to explore the growth, photosynthetic function and related important physiological processes of carbon restriction on macroalgae. The main results are as follows: the low CO_2 supply in seawater (20 ppm) inhibits the relative growth rate (RGR), photosynthetic system activity and NO_3~- absorption rate of Porphyra haitanensis and asparagus, and the inhibition effect of low CO_2 on the RGR of asparagus gracilis is greater than that of Porphyra haitanensis RGR in low daylight intensity (20% of total sunlight), The photosynthetic performance (photosynthetic system activity and photosynthetic rate) and the absorption rate of NO_3~- increased in the RGR of Porphyra haitanensis, but the RGR, the photosynthetic system and the activity of antioxidant enzymes (superoxide dismutase and catalase) and the absorption rate of NO_3~- decreased. Reducing the supply of CO_2 in sea water and reducing the intensity of sunlight at the same time could increase the altar. The content of photosynthetic pigments (chlorophyll a, carotenoid, phycocyanin and phycocyanin) and the ability of algae to resist short-term temperature changes by using HCO_3~- and photosynthetic system. After low CO_2 and low light treatment, the chlorophyll a, carotenoid, antioxidant enzyme activity and photosynthetic system activity of asparagus gracilis can all be in laboratory conditions In addition, the decrease and increase of CO_2 supply in seawater (1000 ppm) decreased the RGR and photosynthetic system activity of the tongue like centipede algae, and reduced the CO_2 supply but increased the phycoerythrocyte and phycocyanin content of the algae. Growth density can reduce the RGR, photosynthetic performance and nitrogen metabolism (NO_3~- absorption rate and nitrate reductase activity); at high density (5 gL~ (-1)) and low CO_2 supply, Porphyra haitanensis showed similar photosynthetic performance; low CO_2 supply and simultaneous high density conditions further aggravated the inhibition effect on the photosynthetic rate of Porphyra haitanensis. In the natural sea area, the high density group (12g/ cluster) grew from the low density group (4g/ cluster) with lower RGR and photosynthetic rate; with the increase of the population density of the algae, the algae entered the deep water layer (1.5m), and the photosynthetic pigment content and photosynthetic rate of the deep water layer grew obviously. Therefore, in the Dragon The effect of balance growth density and depth on the growth and Photosynthesis of asparagus gracilis should be balanced to keep the algae high photosynthetic rate. The photosynthesis behavior of the algae population at different positions in the intertidal zone responds to the difference in biomass density. The experimental results show that the growth is at high tidal level (4h) and the middle tide level (when dried out). The photosynthetic rate of Ulva Ulva increased with the increase of biomass density, and the photosynthetic rate of Ulva Ulva, which grew at low tide level (0 h), decreased with the increase of biomass density. Under the condition of different algae biomass density, the increase of HCO_3~- concentration in sea water obviously increased the total photosynthetic rate of Ulva Ulva (Pg), and increased HCO_3~. - the concentration can not significantly increase the Pg. of Porphyra haitanensis, which indicates that the carbon limitation of the photosynthesis of the Ulva population is higher than the carbon limit of the Porphyra. In addition, the increase of sea water velocity in a certain flow rate ("f3.5 cm s~ (-1)") has no significant effect on the Pg of Porphyra haitanensis and Ulva Ulva. It is concluded that the reduction of CO_2 supply (carbon restriction) can be suppressed. The growth, photosynthetic function and other related physiological processes of Porphyra haitanensis, asparagus and tongue like centipede; high growth density and low CO_2 supply have similar inhibitory effect on the photosynthesis of Porphyra haitanensis; high biomass density inhibits the photosynthesis of alpine, Porphyra haitanensis and Ulva Ulva in the growth period of Porphyra haitanensis and Ulva Ulva The photosynthesis of algae is in a state of carbon restriction, and the carbon limit experienced by Ulva is stronger than that of Porphyra. The results of this study will help to understand the relationship between the supply of inorganic carbon in large algae and photosynthesis, as well as the physiological and ecological functions of the algae in the actual environment conditions such as carbon restriction. The results of algae cultivation provide important theoretical basis and technical support for high-yield and efficient cultivation measures and methods of seaweed.
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：Q945.11

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