Study On Photosynthetic Characteristics In Different Pench Varities

Peach (Prunuspersica (L.) Batsch) is native to China where are rich germplasm. Inthis paper photosynthesis characters of 10 peach varieties were studied. According tobotanical classification with Zhuhua Wang, these varieties can be divided into four types,Prunuspersica (L.) Batsch, P. persica var. nectarine Maxim, P. persica vat. platycarpaBailey and P. persica var. yelloa fleshed. Photosynthetic characteristics of those peachvarieties were comparatively investigated by Li-6400 photosynthesis portable in field fromMay, 2005 to November, 2005, such as diurnal variation in net photosynthetic rate, theeffects of the environmental factors such as light, temperature, concentration of carbondioxide on diurnal variation in net photosynthetic rate, the net photosynthetic rate ofdifferent leaf's location, locations of canopy, leaf's orientations, the pigments content ofChla, Chlb, TChl and Car were also studied. At last, the stomatal density and the ratio oforganize and sponge organize of leaves were discussed in this article. The results werebriefly summarized as follows:1. Diurnal variation in net photosynthetic rate (Pn) in peach leaves was a typical"none-drop" bimodal curve which was determinately regulated by nonstomatal conductance.The environmental factors were very important factors which influenced photosynthesis ofpeach, high temperature of midday straightway made the water in vivo vaporize largely andmaladjusted metabolism, so that influenced photosynthesis enzyme activities, leading todescend of Pn, spraying in farm and other agricultural measures could been used toalleviate noon break2. The annual variation of peach net photosynthetic rate behaved bimodal curvebasically, the first peak occurred August, the second peak occurred October, managementshould been strengthened to improve the nutrient amassment in this period of time.3. For the peach varieties researched, the light compensation points were at32.5-87.7μmol·m^-2·s^-1, light saturation points at l158.3-2888.μmol·m^-2·s^-1. The differentvarieties need different irradiance, available light intensity of Prunus persica var.compressaBean varieties was narrowcorresponding, apparent photosynthetic quantum yield ofPrunus persica (L.) Batsch varieties was higher than other varieties; most of peach varietiesaptly been cultured in the regions where solar radiant intensity was higher possibly,separate varieties which had both low light saturation point and low light compensationpoint aptly been cultured in the regions where solar radiant intensity was not higher or protected cultivation farm possibly.4. Leaves of different peach varieties at different positions had different photosyntheticactivity, the trend primarily presented "low-high-low", the most Pn present to southeast ofthe incident radiation direction, the trend presented "high-low-high" from top to bottom onthe canopy distribution; From fully-expanded leaf of new shoots' terminal to basal of newshoots, from the third to the sixth leaf position, the Pn of new shoot correspondinglyexhibited upper and stably as a whole, the leaves from the third to the sixth leaf positionwere aptly to be used in the determination of peach photosynthesis.5. Different peach varieties had different photosynthetic pigments content, the Chlacontent was from 1.60 to 2.27 mg·g^-1, Chib content was from 0.43 to 0.66 mg·g^-1, Tchlcontent was from 2.16 to 2.80 mg·g^-1, the ratio of Chla/b was from 2.42 to 4.3, Car contentwas from 0.65 to 0.96 mg·g^-1; because both the Tchl content and the ratio of Chla/b of'Xiahui5hao' were highest, 'XiahuiShao' had the more powerful ability of making use oflight; The Tchl of 'Yuhua2hao' was lower and the ration of Chla/b was also lower, whichdemonstrated that the Chlb of 'Yuhua2hao' was higher so as to had more powerful ability ofmaking use of weak light.6. The results obtained by combining the characters of needed light and contents ofphotosynthetic pigment demonstrated that 'Yuhua2hao' should been spread and cultured inthe regions where solar radiant intensity was lower and 'Xiahui5hao' should been spreadand cultured in the regions where solar radiant intensity was higher.