Photosynthetic and carbon sequestration characteristics of three rare and endangered species of Magnoliaceae

Objective  To illuminate the photosynthetic and carbon sequestration characteristics of rare and endangered species of Magnoliaceae, and provide theory and technology bases for their conservation and utilization.

Method  Manglietia aromatica, M. lucida and M. kaifui were studied with LI-6400 portable photosynthetic system measuring photosynthetic characteristics. Their carbon sequestration and oxygen release amounts were estimated to evaluate comprehensively their adaptabilities and ecological effects.

Result  The diurnal variations of net photosynthetic rates of three species displayed bimodal curves with obvious midday depression in July and unimodal curves in October. The daily mean values of net photosynthetic rates of three species in July were 5.35 μmol·m^–2·s^–1 (M. kaifui), 2.87 μmol·m^–2·s^–1 (M. lucida) and 2.78 μmol·m^–2·s^–1 (M. aromatica) successively, and the values in October were 6.46 μmol·m^–2·s^–1 (M. kaifui), 6.24 μmol·m^–2·s^–1 (M. aromatica) and 5.74 μmol·m^–2·s^–1 (M. lucida) respectively. The carbon sequestration and oxygen release amount of three species was in order of M. kaifui>M. aromatica>M. lucida.

Conclusion  The test plants display more vigorous growth in October than July. M. kaifui has the best capacity of utilizing strong light while M. aromatica has the best capacity of utilizing weak light. M. kaifui has the best carbon sequesteration and oxygen release abilities among three species.