The Comparative Research On Four Feijoa Sellowiana Bergs In Photosynthetic Characteristics

Feijoa sellowiana Berg was introduced from abroad in recent years, a coll ection of food, view, green is located in one of three new types of fruit tree. In order to explore it to the introduction environment factor compatibility,In thi s paper, using the Li-6400 portable photosynthesis system,which made by Ll-C OR of Ameircan, to the introduction in the Changsha area cultivation four Feij oa sellowiana such as Poa species'Unique', mid-maturing species'Coolidge'and 'Mammoth', late-maturing species'Triumph', has conducted the system research. net photosynthetic rate(Pn), stomatal conductance(Cond), intercellar CO2 conce ntration(Ci),water pressure deficit(Vpd), tanrspiration rate(Tr), temperature(T), relative humidity of atmosphere(RH)and luminous strength(PAR) were measured Furthemrore, response of Pn to light, response of Pn to CO2 and chlorophyll content of 4 Feijoa sellowiana Berg species were measured. An analysis of net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, trans piration rate, water use efficiency, relative humidity of atmosphere, air temperat ure, photosynthetic active radiation of the diurnal variations and the net photos ynthetic rate of annual variations, in net photosynthetic rate of ecological factor s and physiological relationship between. The main findings are as follows.1. Under net natural state,in different months of a year the diurnal variation in the photosynthetic rate of 4 Feijoa sellowiana Berg observation species we re divided into two kind of types. In April,May,June,September,October,Novemb er species on four kinds of diurnal variation in the photosynthetic rate was sin gle-peak curve; the diurnal variation in July and August were double-peak curv e, there is a clear depression at noon, the reasons for depression in July of no n-stomatal factors, the depression break in August due to stomatal factors.2. The four kinds of Feijoa sellowiana Berg species in the annual variation s of net photosynthetic rate were double-peak curve, the peak appear in the Ju ne and October. In June the net photosynthetic rate in the order from hight to low are as follows:Mammoth 9.95μmolm-2s-1>Coolidge 9.76μmolm-2s-1>Unique 9.46μmolm-2s-1>Triumph 8.47μmolm-2s-1; In October the net photosynthetic rate in the order from hight to low are as follows:Mammoth 9.18μmolm-2s-1>Triu mph 8.97μmolm-2s-1>Unique 8.91μmolm-2s-1>Coolidge 8.88μmolm-2s-1. The four species of net photosynthetic rate in descending order of annual average were: Coolidge 8.337μmolm-2s-1,Mammoth 8.333μmolm-2s-1,Unique 8.236μmolm-2s-1, Triumph7.61μmolm-2s-1.3. The light saturation points of the Feijoa sellowiana Berg were 1307-1 640μmolm-2s-1,the light compensation points was bewteen 17.75 and 33.97μmol m-2s-1, the apparent quantum efficiency were 0.0308-0.0455.Data therefore sho wed that the leaves of Feijoa sellowiana Berg. had the higher utilization effici ency on weak light and strong light. Four species were sun plants. The CO2 s aturation points and compensation points of the Feijoa sellowiana Berg. were 1 032.5-1111μmolmol-1 and 42.82-73.8μmolmol-1, Carboxylating efficiency was between 0.0354 and 0.0446, which indicated that Feijoa sellowiana Berg. speci es had obvious character of C3 type plant. Among four species, Coolidge and Mammoth had the character of liking sun light.,Triumph was tolerant.Mammoth had the stronger utilization efficiency on higher CO2 concentration and Triump h with weekly utilization efficiency of lower CO2 concentration.4. Among the physiological factors, transpiration rate(Tr), stomatal conducta nce (Cond) and intercellular CO2 concentration(Ci) were the major factors that influenced the variations of net photosynthetic rate(Pn),and luminous strength(P AR) was one key ecological factors that influenced the variations of Pn.5. The total chlorophyl content of mature leaf in Feijoa sellowiana Berg i n the order from hight to low are as follows:Unique2.115mgg-1,Coolidge 1.9 74mgg-1,Mammoth 2.458mgg-1,Triumph 2.107mgg-1 There were positive relat ionship between net photosynthetic rate and the total chlorophyl content.