摘要
薇甘菊因为其在新生境的强入侵能力而臭名昭著,有关其入侵的光合生理原因主要集中在叶片光合速率研究,而对非同化器官光合特性少见报道。以叶片为对照,对非同化器官花、果、茎、根的光合电子传递速率、PSII光化效率以及不同器官光合碳固定对群落碳平衡的影响进行了研究,发现尽管非同化器官光合电子传导速率均低于叶片,但是其色素利用效率(叶绿素和类胡萝卜素)显著高于叶片。在生殖生长季节,叶片光合能力明显下降的时期内,非同化器官的光合碳固定对薇甘菊生长起到积极作用。把不同器官的光合碳固定量尺度放大到群体水平发现,基于使用红外线CO2分析法和叶绿素荧光方法计算结果表明,单位土地面积上分布的薇甘菊非同化器官(生殖器官、茎和根等)分别占群体总光合能力的19%和49%,说明非同化器官光合在薇甘菊生长和入侵中可能具有的重要作用。尽管薇甘菊叶片为典型C3植物特征,结果发现了茎以及主叶脉内存在类似C4途径的、具有丰富叶绿体的维管束鞘结构。C4途径的光合效率远比C3植物高可能是薇甘菊非同化器官光合叶绿素效率高于叶片的一个原因,尚需要更多的直接生化证据支持。
Mikania micrantha is notorious for its strong ability to colonize in new habitats.Existing photosynthetic studies have mainly focused on leaves,and less on non-photosynthetic organs such as stems,roots, and reproductive organs.The aim of this study was to clarify the photosynthetic characteristics of each such organ and its possible contribution to total carbon sequestration of the population.By taking the leaf as control,the photosynthetic electron transportation rate（ETR）,PSII photochemical efficiency（ΔF/Fm） and photosynthetic rate（P） under saturation light,chlorophyll content（Chl.a＋b） and carotenoid（Car.） content of the flower,fruit,stem and green root were measured.Although the ETR and ΔF/Fm of these non-photosynthetic organs were lower than those of the leaf,the ETR/Chl.a＋b and ETR/Car.were much higher,indicating that the photosynthetic pigments are more efficiently utilized in non-photosynthetic organs than in leaves.In the reproductive season,the scaling-up of photosynthetic capacity from the organ level to the community level showed that all non-photosynthetic organs took up 19% and 49% of the total carbon sequestration by the IRGA method and the chlorophyll fluorescence method,respectively.Although leaf photosynthesis of this weed is of the C3 type,a C4-like vascular bundle full of chlorophyll was observed in the main vein of the leaf and young stems.In conclusion,the high efficiency of the C4 pathway compared to the C3 pathway might be devoted the high photosynthetic chlorophyll utilization efficiency（ETR/Chl.a＋b） in stems,although more direct evidence is necessary to test this hypothesis.
出处
《生态学报》
CAS
CSCD
北大核心
2009年第1期28-36,共9页
Acta Ecologica Sinica
基金
国家自然科学基金资助项目(30771698)
国家林业局林业有害植物调查专项资助项目
关键词
薇甘菊
非同化器官
光合碳固定
光合电子传导速率
PSII光化效率
饱和光合速率
维管束鞘结构
Mikania micrantha
non-photosynthetic organs
photosynthetic carbon sequestration
photosynthetic electron transportation rate（ETR）
PSII photochemical efficiency（ΔF/Fm）
Saturated photosynthetic rate
C4-like vascular bundle
作者简介
通讯作者Correspondingauthor．E-mail：zygorl@rip．hl．cn
