| The photosynthetic characteristic of seven kiwifruit species such as Actinidia deliciosa Liang et Ferguson., Actinidia chinensis Planch., Actinidia arguta Planch., Actinidia eriantha Benth., Actinidia indochinensis Merr., Actinidia kolomikta Maxim. and Actinidia tetramera Maxim. were conducted under the field conditions. Photosynthetic characteristics of those kiwifruit species were comparatively investigated such as diurnal variation in net Photosynthetic rate,the effects of the environmental factors such as light,temperature, concentration of carbon dioxide on diurnal variation in net Photosynthetic rate,the net photosynthetic rate of different leaf's location and chlorophyll fluorescence characteristics,the pigments content of Chla,Chlb and TChl were also studied. The results were briefly summarized as follows:1.The diurnal variation curves of net photosynthesis rate (Pn), transpiration rate (Tr) and stomata conductance (Gs) of seven species of kiwifruit show double-apex, at 8:00～10:00 when the first peak occurs, the net photosynthetic rate of Actinidia deliciosa Liang et Ferguson., Actinidia chinensis Planch., Actinidia arguta Planch., Actinidia eriantha Benth., Actinidia indochinensis Merr. Actinidia kolomikta Maxim.and Actinidia tetramera Maxim. Were 16.8, 17.8, 11.2, 13.7, 11.2, 10.6 and 7.3μmol·m-2·s-1respectively, the photosynthetic midday depression was caused at 12:00~14:00 and trough occurred at 14:00, at 16:00 a second peak occurs, the net photosynthetic rate are 10.3, 11.8 ,4.8, 6.5, 6.3, 4.6 and 3.6μmol·m-2·s-1 respectively. Intercellular CO2 concentration (Ci) diurnal variation curves of the Actinidia chinensis Planch. was"V" type, and the other species were "W" type.2. Leaves of seven kiwifruit species at different positions had different photosynthetic activity,the trend primarily presented"low-high-low, the Pn of new shoot correspondingly exhibited upper and stably as a whole,the leaves from the third to the seventh leaf position were adaptly to be used in the determination of kiwifruit photosynthesis.3. Different kiwifruit species had different photosynthetic pigments content, the Chla content was from 1.05 to 1.67 mg·g-1, Chlb content was from 0.2 to 0.34 mg·g-1, the ratio of Chla/Chlb was from 4.84 to 5.44, Car content was from 0.31 to 0.43 mg·g-1.4. Chlorophyll fluorescence characteristics of different kiwifruit species were indicated that the fluorescence parameters"Fv / Fm, Fv / Fo"of different species had significant differences, Actinidia deliciosa Liang et Ferguson. and Actinidia chinensis Planch. were significantly higher than other varieties, so the photosynthetic performance of main kiwifruit species in the northern foot of Qinling Mountains such as Actinidia deliciosa Liang et Ferguson. and Actinidia chinensis Planch. were better than other species.5. The light compensation points of seven species of kiwifruit were 32, 48, 19, 43, 22, 21 and 89μmol·m-2·s-1 respectively, light saturation points were 1928, 1980, 1562, 1775, 1620, 1500 and 1250μmol·m-2·s-1.The available light intensity of Actinidia chinensis Planch. was biggest and Actinidia tetramera Maxim. was narrow corresponding; apparent photosynthetic quantum yield of Actinidia chinensis Planch. was higher than other species; the CO2 compensation points were at 32～123μmol·mol-1, CO2 saturation points at 912～1438μmol·mol-1, available CO2 intensity of Actinidia indochinensis Merr.was biggest; carboxylating efficiency of Actinidia deliciosa Liang et Ferguson. was higher than other species. The differentvarieties need different temperature,the optimal temperature of Actinidia arguta Planch. and Actinidia tetramera Maxim.were at 25℃,while the other species of the optimum temperature were around 30℃.
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