景天酸代谢植物仙人掌（Opuntia ficus-indica）光合有效辐射、夜间酸积累与二氧化碳吸收之间的关系

Relationships between Photosynthetically Active Radiation, Nocturnal Acid Accumulation, and CO(2) Uptake for a Crassulacean Acid Metabolism Plant, Opuntia ficus-indica.

作者信息

Nobel P S, Hartsock T L

机构信息

Department of Biology, University of California, Los Angeles, California 90024.

出版信息

Plant Physiol. 1983 Jan;71(1):71-5. doi: 10.1104/pp.71.1.71.

DOI:10.1104/pp.71.1.71

PMID:16662802

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1065988/

Abstract

The influences of photosynthetically active radiation (PAR) and water status on nocturnal Crassulacean acid metabolism (CAM) were quantitatively examined for a widely cultivated cactus, Opuntia ficus-indica (L.) Miller. When the total daily PAR was maintained at 10 moles photons per square meter per day but the instantaneous PAR level varied, the rate of nocturnal H(+) accumulation (tissue acidification) became 90% saturated near 700 micromoles per square meter per second, a PAR level typical for similar light saturation of C(3) photosynthesis. The total nocturnal H(+) accumulation and CO(2) uptake reached 90% of maximum for a total daily PAR of about 22 moles per square meter per day. Light compensation occurred near 0 moles per square meter per day for nocturnal H(+) accumulation and 4 moles per square meter per day for CO(2) uptake. Above a total daily PAR of 36 moles per square meter per day or for an instantaneous PAR of 1150 micromoles per square meter per second for more than 6 hours, the nocturnal H(+) accumulation actually decreased. This inhibition, which occurred at PAR levels just above those occurring in the field, was accompanied by a substantial decrease in chlorophyll content over a 1-week period.A minimum ratio of H(+) accumulated to CO(2) taken up of 2.5 averaged over the night occurred for a total daily PAR of 31 moles per square meter per day under wet conditions. About 2 to 6 hours into the night under such conditions, a minimum H(+)-to-CO(2) ratio of 2.0 was observed. Under progressively drier conditions, both nocturnal H(+) accumulation and CO(2) uptake decreased, but the H(+)-to-CO(2) ratio increased. A ratio of two H(+) per CO(2) is consistent with the H(+) production accompanying the conversion of starch to malic acid, and it apparently occurs for O. ficus-indica when CAM CO(2) uptake is strongly favored over respiratory activity.

摘要

对于一种广泛种植的仙人掌——印度榕仙人掌（Opuntia ficus-indica (L.) Miller），定量研究了光合有效辐射（PAR）和水分状况对夜间景天酸代谢（CAM）的影响。当每日总PAR维持在每平方米每天10摩尔光子，但瞬时PAR水平变化时，夜间H⁺积累速率（组织酸化）在接近每秒700微摩尔每平方米时达到90%饱和，这是C₃光合作用类似光饱和的典型PAR水平。对于每日总PAR约为每平方米每天22摩尔，夜间总H⁺积累和CO₂吸收达到最大值的90%。夜间H⁺积累的光补偿点在每天接近每平方米0摩尔，CO₂吸收的光补偿点在每天每平方米4摩尔。当每日总PAR高于每平方米每天36摩尔或瞬时PAR在每秒1150微摩尔每平方米以上持续超过6小时时，夜间H⁺积累实际上会下降。这种抑制在略高于田间水平的PAR下发生，同时在1周内叶绿素含量大幅下降。在潮湿条件下，对于每日总PAR为每平方米每天31摩尔，夜间积累的H⁺与吸收的CO₂的平均最小比率为2.5。在这种条件下，夜间约2至6小时，观察到最小的H⁺与CO₂比率为2.0。在逐渐干燥的条件下，夜间H⁺积累和CO₂吸收均下降，但H⁺与CO₂的比率增加。每CO₂两个H⁺的比率与淀粉转化为苹果酸过程中伴随的H⁺产生一致，当CAM CO₂吸收比呼吸活动更受青睐时，印度榕仙人掌显然会出现这种情况。