Mutagentic effects of aerospace on Poa pratensis L.. Pt.2: Photosynthesis characters and chlorophyll contents

The dry seeds of Poa pratensis L. 'Nassau' were carried by 'Shenzhou No.3' and three mutants were screened based on presentational characters from the treated plants and asexual reproduced them as PM1, PM2 and PM3. The effects of the space environment on the photosynthesis characters and the contents of chlorophyll of the plants were investigated. Compared to CK, the contents of the chlorophyll a and b were reduced both in PM1 and PM3, and the photosynthetic ability also decreased. The content of the chlorophyll in PM2 increased greatly, but the ratio of the chlorophyll a/b was reduced, and the apparent quantum efficiency and the photosynthetic ability also decreased. The approximately CO2 saturation point of the three mutants were higher than CK, but the CO2 compensation points showed no difference between the mutants and CK. The carboxylation efficiency was PM2<CK<PM3<PM1. (authors)