Provenance D ifferences of Photosynthetic Characters of Taxus chinensisvar. mairei Seedlings and Effect of L ight Environment

The provenance d ifference for pho tosynthet ic characters ofTaxus ch inensis var. mairer seedlingw as stud iedby use of provenance tria l under d ifferent shading cond ition located at Chun’ an of Zhe jiang. The resu lt ind icatedthat there w ere obv ious provenance d ifferences for height grow th, dry matter accumu lation, ch lo rophy ll a, b and thetota l conten,t photosynthesis rate w ith d ifferent geograph ica l genetic variation pa ttern. Seedling he ightw as found tobe positively and sign ificantly re lated to the altitude and long itude of its seed source. Con trast ing to seedling he igh,tdry matter appeared to be certainly and negatively re lated to the a ltitude and long itude of its seed source. Therew ereno obv ious geograph ica l variat ion pattern for ch lo rophy ll content and photosynthesis rate. The provenancesw ithmorech lorophy ll had h igher pho tosynthesis rate and greater dry matter accumulation. Ana lysis demonstrated that there existed great effect o f light env ironm ent on photosynthetic character o f seedling. A t September, the chlorophyll a, band to tal content o f the seed lings under light transm ittance 10% w ere 12. 0%, 16. 1% and 13. 7% more than theones under light transm ittance 25% respect ively. A t O ctober, the chlorophyll a, b and tota l conten t o f the mostprovenances w ere declined under light transm ittance 10% , and average pho tosynthesis rate of the provenances testedw as 13. 7% less than the one under light transm ittance 25%. The change o f ch lorophy ll con tent o f provenance seedling at various grow th stages varied w ith light condition. Under light transm ittance 25% , the content of chlorophy llw as low er atAugus,t h ighest at September, and decreased o r increased slightly at October. Under light transm ittance 10%, the content o f chlorophyll at Octoberw as descended above 20% than one at September.