Effect And Regulating Techniques Of CO₂ Enrichment On Peach Trees In Greenhouse

Based on the greenhouse cultural practice of fruit trees in north China and using3-year-old nectarine trees (Prunus persica var. nectariana cv. Shuguang) of greenhouse as materials in experiment, the research studied the physiological mechanisms and productive effects of CO2 enrichment and worked over the relatively perfect technical system of C02 fertilization which should be suitable to the characteristics the greenhouse culture of north China. Carried through in the demonstration garden of the fruit trees greenhouse culture, the fruit experiment station. College of Horticulture and the modern water-warm glass conservatory of Shandong Agricultural University, Taian, Shandong Province during 1999-2001, the subject would also establish some theory bases for opening out the physiology of fruit trees conservatory culture completely. The main results are as follows:1. CO2 fertilization in greenhouse promoted the photosynthesis of peach trees and made the diurnal curve of photosynthetic rate of peach trees prwnsent double-apex. And photosynthetic acclimation could be seen during the fertilization.2. The respiration and photorespiration rates were affected little by CO2 enrichment under the normal CO2 concentration of greenhouse, while they would descend evidently under the correspondent treatmental CO2 concentration. And the transpiration rate were restrained by CO2 enrichment to some extent.3. CCs fertilization increased the content of chloroplast pigments in the leaf of peach trees in greenhouse and made the Chi a/b value decreased a little. The stornatal density in the leaf would not be effected prominently, but the stomatal conductance would be easily relatively and presented some acclimation to CO2 concentration increase. The photochemical efficiency of Photosystem II didn't increase markedly. Increase of the content of nutrient substances and C/N value during the fertilization in the leaf would effect the floral initiation to some extent.4. The fertilization increased the specific leaf weight and the leaf area of peach trees in greenhouse, while made the water content in the leaf drop. And C02 enrichment heightened the yield and quality of the fruits of peach and the positive effect to the latter exceeded that to the former.5. The stages of shoot-growing, fruit-inflating, fruit-rendering and fruit ripeness are the key periods of CO2 fertilization of greenhouse culture of fruit trees. The manners of whole-day and single-afternoon CO2 fertilization are not proposed. The whole time of fertilization every day should be over 2 hours. The manner of continuum fertilization is proposed and during cloudy and rainy days fertilization should be stopped. The CO2 concentration of 800-900u,lT' is the moderate enrichment concentration, SOOulT1 the most economical.