Research On Photosynthetic Characteristics Of Osmanthus Fragrans

Sweet osmanthus(Osmanthus fragrans) is one of the Top Ten Traditional Flowers in China. Sweet osmanthus is a both ornamental and practical tree. Studying the photosynthetic characteristics of Osmanthus fragrans, was using for the high yield varieties selection and management of scientific evidence.Studies on photosynthetic characteristics of Osmanthus fragrans'Zaoyingui'lasted half of a year. The experiments were carried out by using the portable photosynthetic meraurement CIRAS-2. Diurnal and month varitey of photosynthesisi factors were studied. Also, the effects of leaf age, leaf opposition, leaf cholrophyll content, LMA, leaf direction, and PAR to Pn were studied. Furthermore, the relationship between photosynthetic factors and environment factors were analysised. The photosynthetic characters of three Osmanthus fragrans cultivars were compared. The results showed that:1. Diurnal changes in Pn of Osmanthus fragrans'Zaoyingui'were different in different months. It presented single peak curve in June, October, and November, while there were double peak curve in July, August, and September. The midday depressions of Pn were mainly due to stomatal factors and non-stomatal factors. Seasonal change of Pn was a single peak curve, and peak was in July. The light use efficiency presented V curve, but the water use efficiency didn't have obviouse change. Pn had singificant and positivelv correalation with Tr, Cond, and had negatively correlated with Ci. But the changes of WUE and Pn had no significant relationship.2. The relationship among age, leaf opposition, leaf chlorophyll content and Pn was manifest. The Pn of middle and southern leaves were higher than the other directions. The contents of Chla were much more than Chlb, the content of Chll(a+b) were changed with months. Chlla/b had no significant different changes. SLW was highest in July.3. LCP of Osmanthus fragrans'Zaoyingui'are within 37⁴1μmol·m^-2·s^-1, and LSP are within 1000¹685μmol·m^-2·s^-1 in different months. The AQY are within 0.0376⁰.041. These evidences clearly proved that Osmanthus fragrans'Zaoyingui'is heliophile plant.4. The photosynthetic characteristics of different Osmanthus fragrans cultivars were obvious different. The highest Pn, Tr, WUE, QUE was Osmanthus fragrans'Zaoyingui'; Osmanthus fragrans'Sijigui'was the second, Osmanthus fragrans'Qiugui'was the third. Osmanthus fragrans'Sijigui'was peticular than others.