Studies On Photosynthetic Characteristics Of Dongkui And Biqi Red Bayberry

Myrica rubra has high economic, ecological and social benefits. Study on photosynthetic and physiological characteristics of dongkui and biqi red bayberry, the aim is providing scientific basis for superior variety selection and the efficient cultivation and management. In this paper, dongkui and biqi red bayberry are selected as test materials. The experiments are carried out during 2008.04^-12 by using the portable photosynthetic measurement LI-6400. The anatomical characteristics of leaves, specific leaf weight, the contents of chlorophyll and sugar etc. of dongkui and biqi are studied. The results are as follows:1. Diurnal changes of Pn of dongkui and biqi presents two peaks in April, July and September, while there is only one peak in December. The midday depressions of Pn in April and July are mainly due to stomatal factors, and non-stomatal factor has great influence on midday depression in September. Seasonal change of Pn of dongkui and biqi is a single peak curve, and the highest in July, the lowest in December.2. LCP of dongkui and biqi are within 25-53μmol·m-2·s^-1, and LSP are within 335.05-700.09μmol·m-2·s^-1, therefore dongkui and biqi have the characteristics of heliophyte. CCP of dongkui and biqi are respectively 39.764μmol·m-2·s^-1 and 33.941μmol·m-2·s^-1, and CSP are respectively 1030μmol·m-2·s^-1 and 1173.333μmol·m-2·s^-1. Dongkui has higher AQY, CE, Pm and larger range of available PAR than biqi.3. The Pn of young leaves (leaf expansion 10 d), half-year-old leaves, one-year-old leaves, and two-year-old leaves of dongkui are higher than biqi. There are different Pn in different location canopy leaves of dongkui and biqi red bayberry, there also existed some differences in different orientations leaves of dongkui and biqi.4. SLW of biqi red bayberry is higher than dongkui. There are some correlations between SLW and daily average values of Pn. Contents of Chlorophyll a, b and total of biqi slightly higher than dongkui, while there is no significant difference in Chlorophyll a/b of dongkui and biqi. These differences are not mainly reasons that cause difference in Pn of dongkui and biqi. The contents of soluble sugar, reducing sugar and starch of biqi red bayberry are higher than dongkui. There are some correlations among contents of soluble sugar, reducing sugar, starch and daily average values of Pn of dongkui and biqi.5. The stomatal densities of dongkui red bayberry leaves are less than biqi, while its stomatal length and width are larger than biqi. There are no significant differences in length/width ratio of stomata of dongkui and biqi. The differences of stomatal densities, stomatal length and width may cause the difference of Pn of dongkui and biqi. There are no significant difference among the thickness of leaf palisade tissue and spongy tissue, and the rate between palisade and spongy tissue of dongkui and biqi. These indicate that the anatomical structure of dongkui and biqi red bayberry leaves may have no obvious influence on their photosynthesis.