The effects of light intensity and nitrogen on the physiology of the red macroalgae Gracilaria lemaneiformis
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PDF HTML阅读 XML下载 导出引用 引用提醒 光照强度和氮营养盐浓度对龙须菜生理代谢的影响 DOI: 作者: 作者单位: 汕头大学 理学院 生物系, 广东 汕头 515063 作者简介: 张清芳(1989-),女,硕士,从事植物生理研究.E-mail:zhangqingfang0629@163.com 通讯作者: 中图分类号: S968 基金项目: 广东省海洋与渔业局科技推广专项项目（A201405B06）. The effects of light intensity and nitrogen on the physiology of the red macroalgae Gracilaria lemaneiformis Author: Affiliation: Department of Biology, Shantou University, Shantou 515063, China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以龙须菜（+=2：1）为氮源配制人工海水，将在低光低氮（L-N-）条件下培养的龙须菜部分给予高光照处理（L+N-），同时另一部分在给予高光照的同时给予更充足的氮源（L+N+），通过测定3种不同处理条件下物质积累、光合色素以及碳氮代谢中的关键酶等多种生理指标，探讨光照强弱与氮源多寡对龙须菜生理代谢的影响。结果表明，在低氮培养时，高光可使藻体可溶性蛋白、含水率、藻红蛋白和叶绿素a的含量下降，而可溶性糖含量上升13.67%；高光培养时，高氮使可溶性蛋白、含水率、藻红蛋白和叶绿素a的含量上升，而可溶性糖含量下降16.3%；相对于低光低氮（L-N-），高光高氮（L+N+）条件培养使藻体中可溶性蛋白和藻红蛋白含量增加，其含水率、叶绿素a和可溶性糖含量并无显著性差异（>0.05）。从上述结果可以看出，补充氮源能够在一定程度上消除高光照对藻体产生的影响，保证藻体基本生理状态不发生变化的情况下积累蛋白（氮源）。同时补充氮源使得谷氨酰胺合成酶（GS）和天庚酮糖-1，7-二磷酸酶（SBPase）的表达均下调，也反映了光合作用所产生的三碳化合物在氮源充足的条件下主要流向了氮循环。而高光照并未对碳氮代谢关键酶的表达产生影响，可能通过直接破坏叶绿素a而影响藻体的光合作用。 Abstract:, which has rich agar, comprises the third-largest seaweed cultivation industry group in China, after . As light intensity gradually strengthens in summer, in the surface layer of cultivation areas becomes green, or even white, yet the internal part remains dark red. was cultured in artificial seawater with inorganic nitrogen (NO3-:NH4+=2:1). Three conditions:low light low nitrogen (L-N-), high light low nitrogen (L+N-) and high light high nitrogen (L+N+) were settled in this study. The impact of light intensity and nitrogen on physiology and metabolism of was studied through measured matter accumulation, photosynthetic pigment, key enzyme during carbon and nitrogen metabolism under three conditions. The results showed that, compared with the L-N-group, the L+N-group showed decrease of soluble protein, water, phycoerythrin and chlorophyll-a, but the amount of soluble sugar increased 13.67%. Compared with the L+N-group, the L+N+ group showed the increase of soluble protein, water, phycoerythrin and chlorophyll-a, but the amount of soluble sugar decreased 16.3%. Compared with the L+N+ group, the L-N-group showed the increase of soluble protein, phycoerythrin, but there is no significant difference in its amount of water content, chlorophyll-a and soluble sugar. These results confirm that a sufficient amount of nitrogen can weaken the negative effects of high-intensity light on a red macroalgae. 参考文献 相似文献 引证文献Keywords:
Phycoerythrin
Light intensity
Light intensity
Ribulose
Carbohydrate Metabolism
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The major light-harvesting complex (LHCIIb) of photosystem II can be reconstituted in vitro from its recombinant apoprotein in the presence of a mixture of carotenoids and chlorophylls a and b. By varying the chlorophyll a/b ratio in the reconstitution mixture, the relative amounts of chlorophyll a and chlorophyllb bound to LHCIIb can be changed. We have analyzed the chlorophyll stoichiometry in recombinant wild type and mutant LHCIIb reconstituted at different chlorophyll a/b ratios in order to assess relative affinities of the chlorophyll-binding sites. This approach reveals five sites that exclusively bind chlorophyllb. Another site exhibits a slight preference of chlorophyllb over chlorophyll a. The remaining six sites are filled preferentially with chlorophyll a but also tolerate chlorophyll b when this is offered at a large excess. Three of these chlorophyll a-affine sites could be assigned to distinct positions defined by the three-dimensional LHCIIb structure. Exclusive chlorophyll b sites complemented by chlorophyll a sites that are selective only to a certain extent are consistent with the observation that chlorophyllb but not chlorophyll a is essential for reconstituting stable LHCIIb. These data offer an explanation why a rather constant chlorophyll a/b ratio is observed in native LHCIIb despite the apparent promiscuity of some binding sites.
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In order to research photosynthetic capacity of main apricot cultivars in Xinjiang,taking ten main apricot cultivars in Xinjiang as materials,different photosynthetic parameters were determined by using Li-6400 portable photosynthesis system,and the light response curves were drawed.The results showed that when light intensity increased,net photosynthetic rate,stomatal conductance and transpiration rate in all varieties were increased,but intercellular CO2 concentration was decreased.The photosynthetic indexes existed significant differences among some cultivars,and Xiaobaixing cultivar had more sensitive response to light intensity,with light intensity increasing,it's net photosynthetic rate was increased rapidly.In different light intensities,the photosynthetic rate of Xiaobaixing cultivar was the highest.It's net photosynthetic rat reached the maximum value of 8.66 μmol/(m2·s) when light intensity was 1 800 μmol/(m2·s).The results indicated that Xiaobaixing cultivar was the strongest photosynthetic capacity,photosynthetic rate of Hongteke cultivar was the lowest,and the other cultivars at the middle.
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Abstract Pigment extracts (phycoerythrin and chlorophyll) and apparent photosynthetic rates under selected wavelengths for the benthic marine alga Eucheuma isiforme var denudatum are presented. Plants were sampled from March to September during vegetative growth. The study shows that (a) total pigment content exhibits a three-fold increase from young to mature plants, (b) the concentration of phycoerythrin changes from 0·36 nm/mg dry wt to 1·07 nm/mg dry wt and the chlorophyll concentration changes from 0·03 nm/mg dry wt to 0·57 nm/mg dry wt and (c) an initial phycoerythrin/chlorophyll ratio of 20 : 1 decreased to 1 : 1 during the summer months. The September ratio increased to 3 : 1. E. isiforme var denudatum exhibited strong correlations between pigment concentration and apparent photosynthetic rates. Blue and red light exhibited correlations (0·9447 and 0·7915 respectfully) to chlorophyll. Green light exhibited the strongest correlation (0·4298) to phycoerythrin. Physical environmental fluctuations during the summer are viewed with respect to the correlations between pigments and apparent photosynthetic rates. These comparisons indicate that E. isiforme var denudatum may chromatically adapt to the benthic marine environment by changes in pigment concentration.
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Photosynthetic response curves to CO 2 concentration and light intensity were determined for the soybean varieties ‘Hark’ and ‘Chippewa‐64’. At light intensities above 5,380 lux, the photosynthetic rates of both varieties were limited by the CO 2 concentration of the surrounding atmosphere within the range investigated (270 to 1670 ppm). At normal atmospheric CO 2 concentration (300 ppm), photosynthesis of both varieties was light saturated at about 21,530 lux. At a CO 2 concentration of 1670 ppm, photosynthesis was not light saturated in either variety at the highest light intensity tested (75,350 lux). The photosynthetic rate of the variety Hark was higher than that of the variety Chippewa‐64 at 45 of the 48 combinations of light intensity and CO2 concentration tested.
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A quantitative estimate was made of the interference by chlorophyll b in the fluorometric determination of chlorophyll a using an Aminco-Bowman spectrofluorometer. The undegraded (or 'living') chlorophyll a concentration was underestimated by an amount equal to the concentration of chlorophyll b present. The value for chlorophyll a uncorrected for phaeophytin was increased by 30% of the chlorophyll b concentration. The acetone to water ratio was found to affect the acidification factor only at aqueous acetone concentrations above 90%. The need for standardization of solvent and wavelengths is discussed, and the implications of chlorophyll b occurring in marine samples are considered.
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The relation of photosynthesis to light condition was investigated with soybean plant population. Diurnal changes of photosynthesis, horizontal light intensity both total and diffuse were recorded on 3 or 4 successive days of various weather conditions. From these data, light-photosynthesis relation was investigated with refernce to the proportion of diffuse light component to the total light. On the other hand, the manner of light distribution on photosynthetic system was investigated under various light conditions by measuring the illumination intensity on individual leaves. The results obtained were as follows: (1) Photosynthetic rate of soybean plant population depended not only on total amount of light but also on its proportion of diffuse light. When the total light intensity was same, the photosynthetic rate varied with the proportion of diffuse light, that is, the photosynthetic rate increased with increase in the proportion of diffuse light. (2) Under fine or clear condition the proportion of diffuse light was very low and many sun flecks were formed on photosynthetic system of the population. A major part of light was concentrated to these limited regions, resulting in a uneven distribution of light on photosynthetic system. On the contrary, under hazy or clowdy condition, the proportion of diffuse light was higher and distribution of light on photosynthetic system was relatively even horizontally as well as vertically. (3) Rates of the photosynthesis under various light conditions were calculated from illumination intensity at surface of leaves and light-photosynthesis curve of single leaf. Then, the photosynthetic rates so obtained were compared with each other. Under same total light intensity, the calculated rate was consistently higher when the proportion of diffuse light was higher, Further, the ratio of the two rates, calculated under higher as well as lower proportion of diffuse light, was fairly coincided with the same kind ratio of the two rates obtained by direct measurment of photosynthesis of population. From this, it was concluded that a higher photosynthetic rate under a higher proportion of diffuse light based mainly on more favorable distribution of light on photosynthetic system-even distribution of light.
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