Key Cultivation Techniques And Their Physiological Basis Of Nectarine And Platycarpar In Greenhouse

The control of ambient condition(light, temperature, humidity and gas) and the regulation of fruit development, especially the coordination the balance between its vegetative and reproductive growth are crucial for high yield and high quality of fruits cultivated in greenhouse. This research were aimed to study the practical benefits of some novel methods for growth control, to highlight possible negative effects, particularly on fruit quality, growth, photosynthesis, and to improve our understanding in the effects of root confinement and Paclobutrazol(PP333) foliar spraying in canopy development control. Moreover, to study the characteristics of fruit development and the morphological and physiological acclimation in the protected cultivation, will surely be beneficial for screening improved varieties of special peach in greenhouse.This study was performed during a period of three years (2002~2004) on seedlings of Prunus Persica Var. Platycarpa , Prunus Persica var. Nectarine Zaohongbaoshi, HuYou004,018 and seven-year-old fruiting Nectarine cv. HuYou004 in Shanghai. Trees were trained to central leaders and planted at an in-row spacing of 1m with 1.5m, 2m between rows. When planting, different ways of root confinement were performed as: control-trees set in holes dug with a shovel just large enough to accommodate the root system(volume0.21m3/plant); root-restriction using nylon membranes with a mesh size of 10mm (volume 0.067m3/plant); root-confinement using bamboo basket with a mesh size of 30mm (volume 0.0567m3/plant); root-restriction using non-woven synthetic fabric(standard 0.5kg/m2, thick 0.20mm, volume 0.50m3/plant).During fruit growth, Paclobutrazol was further applied through sequential foliar spraying(0~1500mg/l at the end of Stage I, once again 30 days later). The experimental design was a randomized complete block with 10~ 30 replications, depending on the characteristic measured. The main results as following: 1 The sensitivity of different Nectarine varieties to root confinement was obviously distinct: Nectarine cv. HuYou018 > Zaohongbaoshi > HuYou004.Root-restriction using nylon membranes was revealed to be applicable for regulation of fruit growth and development in Nectarine Zaohongbaoshi and HuYou004, while root confinement using bamboo basket was suitable for Nectarine HuYou018. Besides, the effects of different root confinement ways were obviously different for the same Nectarine cv.. Take Zaohongbaoshi as an example, root-restriction significantly affected total number of all sorts of fruiting branches and the percentage of total fruiting branches in all branches, the above two parameters for plants grown in nylon membranes were larger than those in bamboo basket containers and control. Root-confinement using nylon membranes significantly reduced shoot vegetative growth both in elongation and enlargement. Also, root constriction could improvedhorizontal distribution, MFIA, TDP of leaves in canopy and reduce the loss of light in crown. Moreover, root confinement has significantly affected leaf soluble protein, dry weight of leaves in one-year shoots. The results further indicated: the seasonal variation of soluble carbohydrates content in leaf peaked twice hi plants treated with root confinement. And the temporal changes in soluble carbohydrate content peaked about one month earlier in - bamboo basket confinement than that in other treatments.2 To characterize gas exchange of young Nectarine trees hi response to root confinement was aimed to enhance our understanding of the physiological changes underlying growth repression. Pn in leaf went up as light intensity ascending, but the degree of Pn increase was significantly different among treatments. Pn of Nectarine was saturated at around 800 mol.m-2.s-1treated in control, 1200 mol.m"2.s"'inroot-restriction using nylon membranes and 1600 mol.m-2.s"1 in using bamboo basket respectively. And leaf WUE was enhanced obviously through reducing the Tleaf of plants treated with root confinement.3 PP333 foliar spraying significantly increa...