Studies Of Sweet Persimmon's Performance In The Rigion Of Baoding And Its Tissue Culture Technology

The region of Taihang mountain in HeBei is the main persimmon producting area of our country, but it had the problem that variety structure was simplistic, most of them were astringent persimmons,whose fruies need artificial astringency removal before using for food,and the storage-enduring is not good. Compare to it, the fruit of sweet persimmon coud remove astringency naturally. So developing sweet persimmon has important significance for regulating persimmon cultivation structure of Hebei.The experiment was carrid out to study the biological character photosynthetic character and tissue culture of sweet persimmon. The results showed that sweet persimmon could be successfully grown in the region of Baoding. The suitable varieties are Tuyou'and 'Cilang', 'Chansiwan' is pollenizer. The scion of younge perfectly sweet persimmon CV. 'Fuyou'whose rootstock is Junqianzi has excellent graft compatibility when it was grafted with Junqianzi, the percentage of viability could be as high as 94.8%.In the studies on photosynthesis using an American photosynthetic apparatus CI-301 PS. The result showed that the variations in photosynthetic rate were found both among the leaves at different shoot position of the same variety and different varieties, the net photosynthetic rate was 6.94-10.8 CO2 v mol ?m"2 ?s"1. The light saturatipn point of the tree species was 1051-1287 n mol ?m"2 ?s'1, and light compensation point was 23-42 n mol mm'2 ^"'.The daily variation curve of photosynthetic rate in clear day was measured as a shape with double peaks, the highest peak appeared at about 10:00, and the sub-peak at 4:00 in afternoon.In cloudy day, it was measured as a shape with one peak, which appeared at 12:00-14:00. The curve of annual variation of photosynthetic rate also has two peaks, occurring in June and in August respectivly. Transpiration rate has positive correlation with photosynthetic rate, stomatal resistance has negtive correlation with photosynthetic rate. The main factors affecting photosynthetic rate of sweet persimmon were intensity of illumination, temperature, raletive humidity and CO2 concentration. The results of multiple regression analysis showed that photosynthetic rate was closely related with environmental factors. The R2 of three cultivars were all higher than 75%.The results of studies on tissue culture were as follows: sprouting bud^obtained from dormant shoot which cultured in water and dark was the best explant. Explant browningwas related with the age and size of explant. Using young and big material could lesson the extent of explant browning. Using optimum plant growth regulators ZT and IAA could prevent explant browning effectivly and increas the rate of differentiation. The optimum growth regulators in the culture of leaves and stem section without axillary buds were also ZT and IAA, the favorit concentration for stem were ZT 2mg ?L"1-. IAA 0.05 mg ?L"1, and ZT l~2mg ?L""> IAA 0.1~0.2 mg ?L"1 for leaves.In the dark condition, the differentiation of explant and bud proliferation rate could be increased, the suittable period were 15d and lOd respectivly for stem and leaves. The results'of studies on coagulator shows that Beilining is better than agar.