Abstract: Growth and photosynthetic characteristics of Flaveria bidentis were studied. The results provided scientific basis for effective controlling Flaveria bidentis. Flaveria bidentis were sown by hand in no tillage. The Flaveria bidentis indexs of seedling emergence rate,plant height growth,leaves growth and fresh weight changes per square unit were measured. Relationships between Flaveria bidentis seedling emergence rate and soil temperature and moisture were surveyed. Flaveria bidentis leaves chlorophyll content were measured using acetone direct lixiviating method at seedling stage,vegetation period and early flowering stage. Net photosynthetic rate and diurnal changes of net photosynthetic rate at different growth stage of Flaveria bidentis leaves,and photosynthesis-light response curve were measured using LI-6400 portable photosynthesis system. The results showed that,Flaveria bidentis seedling emergence peak occurred after sown 8 weeks,and the seedling emergence rate was 74. 67%. Average soil temperature was more than 10℃ Flaveria bidentis beginning emergence,and the optimal soil average temperature for Flaveria bidentis emergence was 25℃. It had little effect on Flaveria bidentis emergence when the soil temperature and moisture was at 25% to 30%. The plant height and leaf number of Flaveria bidentis had little change before sown 8 weeks,but from sown 8 to 22 weeks grown rapidly. The final plant height and leaf number was 280 cm and 44 leaves.The fresh weight of Flaveria bidentis per square unit increased rapidly from sown 8 to 22 weeks,and the average increment one week was 2 275 g. The fresh weight maxium value was 26 781 g /m2 after sown 22 weeks. Flaveria bidentis leaves chlorophyll content were 0. 392%,0. 409% and 0. 508% respectively at seedling stage,vegetation period and early flowering stage. Flaveria bidentis leaf most net photosynthetic rate were 23. 6,37. 5 and 41. 5 μmol /(m²·s) respectively at seedling stage,vegetation period and early flowering stage. Diurnal changes of net photosynthetic rate were one-peak curve at the three growth stage of Flaveria bidentis leaves. There was no photosynthesis midday depression phenomenon. The peak of net photosynthetic rate was measured at 11: 00 a. m.. The curve of durnal changes of net photosynthetic rate were different from each other which measured at the three growth stage of Flaveria bidentis. Light saturation point of photosynthesis was 1 512 μmol /(m²·s). Light compensation point of photosyntesis of Flaveria bidentis leaves was 53. 7 μmol /(m²·s).

Key words: Flaveria bidentis, Growth characteristic, Photosynthetic characteristic

CLC Number: 

• Q948