Characteristics of photosynthesis in four rare ornamental bamboo species

Abstract

The gas exchange, chlorophyll fluorescence properties and absorbed light allocation were investigated in four bamboo species: Phyllostachys aurea cv. luteosulcata, Phyllostachys aurea cv. viridisulcata, Phyllostachys aureosulcata f. spectabilis, Phyllostachys nigra. The results show that the leaves of these bamboo species demonstrated different photosynthetic characteristics in net photosynthetic rate (Pn), absorbed light allocation and the electron transport. However, these differences are not due to the stomatal factor. The highest Pn in Phyllostachys aurea cv. luteosulcata was resulted from the higher carboxylation efficiency and the lower electron transport flow through photorespiration. A higher rate of increase in efficiency of energy conversion of open PSⅡ(Fv′/Fm′), actual PSⅡ efficiency (ΦPSⅡ), photochemical quenching (qP) and electron transport rate (Jf) and a lower rate in non-photochemical quenching (NPQ) were noticed in Phyllostachys aurea cv. viridisulcata with increase in light intensity. However, the proportion of photosynthetic electron transport to photorespiration reached 50% in Phyllostachys aurea cv. viridisulcata. These results indicate that the photorespiration might become an efficienty protective mechanism of photosynthetic apparatus by dissipating excess light energy. Although Phyllostachys aureosulcata f. spectabilis and Phyllostachys nigra had higher energy dissipation capacity as is indicated by a higher NPQ and had lower Fv′/Fm′, ΦPSⅡ, qP than two other species did, their higher photorespiration suggested that the photorespiration and the non-radiative dissipation of absorbed excitation energy through NPQ were the main mechanism in protecting photosynthetic apparatus under such conditions.

Keywords

• bamboo
• photosynthesis
• chlorophyll fluorescence
• absorbed light allocation
• electron transport