五种彩叶植物光合日变化研究

采用美国生产的LCI便携式植物光合测定仪测定自然生长的红龙草、黄金榕、变叶木、红背桂和鹅掌柴等5种彩叶植物的净光合速率（Pn）、气孔导度（Gs）、细胞间隙CO2浓度（Gi）、蒸腾速率（Tr）和气孔限制值（Ls）等光合特征值的日变化。结果表明：红龙草、黄金榕和变叶木的Pn、Gs和Tr日变化曲线呈“单峰”型,其Pn、Gs和0在10：00达到高峰;红背桂和鹅掌柴的Pn、Gs和Tr日变化曲线呈“双峰”型,其Pn、Gs和Tr分别在10：00和16：00达到高峰,且第1个高峰值大于第2个高峰值。5种彩叶植物的Ci日变化均先降后升,红龙草、黄金榕和变叶木的Ci在14：00出现低谷,红背桂和鹅掌柴的Ci在10：00出现低谷。5种彩叶植物的Ls日变化均先升后降,红龙草和变叶木的Ls在14：00迭最高值,黄金榕的Ls在12：00达最高值,红背桂和鹅掌柴的Ls在10：00达最高值。

Diurnal changes of photosynthetic characteristics of five colorful plant species

Diurnal changes of net photosynthetic rates, stomatal conductance, intercellular carbon dioxide concentration, transpiration rates and stomatal limits of photosynthetic characteristics of Altemanthera ficoidea cv. ruliginosa, Ficus microcarpa, Codiaeum variega- tum var. pictum , Excoecaria cochinchinensis and Schefflera octophylla were studied under natural conditions by using LCI portable pho- tosynthesis system. The results showed that, the diurnal changes of Pn, Gs and Tr of A.ficoidea cv. ruliginosa, F. microcarpa and C. variegatum var. pictum emerged a single-peak curves with the peak at 10 ： 00, whereas those of E. cochinchinensis and S. octophylla ex- hibited double-peaks curves with the first peak at 10：00 and the second peak at 16： 00, and the first peak was higher than the second peak. The diurnal changes of Cs of five colorful plants decreased followed by an increase. The minimum Ci of A.ficoidea cv. Ruligino- sa, F. microcarpa and C. variegatum var. pictum occurred at 14：00 while that of E. cochinchinensis and S. octophylla appeared at 10： 00. The diurnal changes of Ls of five colorful plants increased followed by an decrease, which reached maximum at 14：00 for A.ficoidea cv. ruliginosa and C. variegatum var. pictum, at 10：00 for E. cochinchinensis and S. octophyUa and at 12：00 for F. microcarpa, re- spectively.