Salinity Effects on Photosynthesis, Carbon Allocation, and Nitrogen Assimilation in the Red Alga, Gelidium coulteri.
Salinity Effects on Photosynthesis, Carbon Allocation, and Nitrogen Assimilation in the Red Alga, Gelidium coulteri.
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DOI：
10.1104/pp.88.3.690
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发表时间：
1988-11
期刊：
影响因子：
7.4
通讯作者：
B. Macler
中科院分区：
文献类型：
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作者：
B. Macler
盐度变化对潮间带红藻Gelideum coulteri Harv.生理的长期影响都进行了评估。将植物从每升30克盐度转移到盐度从0到50克每升的基质中。在适应5天和5周后，对生长速率、琼脂、光合作用、呼吸作用和各种代谢产物进行量化。5天后，所有盐度改变的植物的生长速度都较慢。经过5周的适应，生长速度从这些值恢复，但盐度在每升10克及以下时，组织漂白和死亡。在高盐度和低盐度下，光合作用O(2)释放在5d后均低于对照，且不随时间变化。改变的盐度的碳固定在5天后没有变化，但在5周后下降到每升25克以下和40克以上。盐度越低，呼吸作用越强。盐度变化5天后，藻胆蛋白和叶绿素含量均降低。这些下降持续在较低的盐度，然后稳定在5周后。在较高的盐度下，叶绿素随着时间的推移而恢复。盐度较低时蛋白质的减少在数量上可归因于藻胆蛋白的丧失。在所有测试的盐度中，总氮水平和C/N比几乎是恒定的。进入谷氨酸和天冬氨酸的碳流量随着盐度的降低和增加而减少。甘氨酸、丝氨酸和乙醇酸水平随着盐度的升高和降低而增加，表明光呼吸受到刺激。细胞壁组分琼脂随着盐度的降低而增加，但在较高和较低盐度下生物合成均受到抑制。随着盐度的增加，储藏化合物的花色苷含量增加。这些证据表明，盐度变化会直接影响光合作用、呼吸作用和氮同化，并间接影响光合作用产物的流动，从而产生胁迫反应。在低盐度下，呼吸和光呼吸超过光合作用，结果是致命的。在较高盐度下，虽然光合作用受到抑制，但呼吸作用较低，固碳足以抵消光呼吸增加的影响。
The long-term effects of altered salinities on the physiology of the intertidal red alga Gelidium coulteri Harv. were assessed. Plants were transfered from 30 grams per liter salinity to media with salinities from 0 to 50 grams per liter. Growth rate, agar, photosynthesis, respiration, and various metabolites were quantified after 5 days and 5 weeks adaptation. After 5 days, growth rates were lower for plants at all altered salinities. Growth rates recovered from these values with 5 weeks adaptation, except for salinities of 10 grams per liter and below, where tissues bleached and died. Photosynthetic O(2) evolution was lower than control values at both higher and lower salinities after 5 days and did not change over time. Carbon fixation at the altered salinities was unchanged after 5 days, but decreased below 25 grams per liter and above 40 grams per liter after 5 weeks. Respiration increased at lower salinities. Phycobili-protein and chlorophyll were lower for all altered salinities after 5 days. These decreases continued at lower salinities, then were stable after 5 weeks. Chlorophyll recovered over time at higher salinities. Decreases in protein at lower salinities were quantitatively attributable to phycobili-protein loss. Total N levels and C:N ratios were nearly constant across all salinities tested. Carbon flow into glutamate and aspartate decreased with both decreasing and increasing salinities. Glycine, serine, and glycolate levels increased with both increasing and decreasing salinity, indicating a stimulation of photorespiration. The cell wall component agar increased with decreasing salinity, although biosynthesis was inhibited at both higher and lower salinities. The storage compound floridoside increased with increasing salinity. The evidence suggests stress responses to altered salinities that directly affected photosynthesis, respiration, and nitrogen assimilation and indirectly affected photosynthate flow. At low salinities, respiration and photorespiration exceeded photosynthesis with lethal results. At higher salinities, although photosynthesis was inhibited, respiration was low and carbon fixation adequate to offset increased photorespiration.