| Cultivation of prunus persica in heliogreenhouse is developing in the previous years.but because of lacking understanding of the major environmental factors in heliogreenhouse , only depending on the experience obtained through clean cultivation or blindly learning the experience from other places, fruit farmers have not profited from cultivating prunus persica.. The variation law of major environmental factors and their effects to the photosynthesis of prunus persica. The results demeostrate that : 1) In the first 10-day-period in January, when the mean temperature is 2.2C, the temperature inside the heliogreenhouse can be as high as 10.3C, and this temperature can meet the needs of prunus persica for germinating and blossoming. But during this period, the earth temperature inside the heliogreenhouse is rather low, which is from 5.7C-7.6C.and cannot meet the growth and development of the roots. So plastic film will be used to cover the top of greenhouse after being spread on and warming up the floor first. 2) From the second 10-day-period of January to the second 10-day-period of March, the mean temperature inside heliogreeenhouse is 10.3C to 29.5C, and this temperature can nicely meet the needs of prunus persica for its germination ,florescence , bud bursting, fruit's enlargement and growth of young shoots. 3) The fruit of prunus persica is enlarging and its core is hardening from the third 10-day-period of march to the second 10-day-period of April, and the mean temperature inside the heliogreenhouse is between 20.7-23.2C. The maximum temperature is as high as 27.7C. 4) the fruit of prunus persica ripens and get colors from the second 10-day-period of April to the first 10-day-period of May. The mean temperature inside heliogreenhouse is between 22.3-23.2C,and the maximum temperature could be as high as 22.7-31.0C, so attention should be paid to aeration and transparency. 5) It is low intensity of illumination period all the way from the first 10-day-period of January to the third 10-day-period of March in Yangling shaanxi. Although the intensity of illumination gets stronger after the first 10-day-period of April, the intensity of illumination inside heliogreenhouse is 59-86% the one outside the heliogreenhouse on average. 6) The relative humidity inside heliogreenhouse is lower than that outside heliofreenhouse, usually 65.4%-94.7%. In the day time, with the increase of temperature, the relative humidity is reduced gradually. In a fair day, the relative humidity inside heliogreenhouse can be as low as 26%. 7) Prunus persica cultivated in heliogreenhouse has a higher net photosynthetic rate at 10am and 14pm in a clear day, while a lower rate at 12.00, and demonstrates as bimodal distribution curve. In a overcast day, a monomodal distribution curve , which shows maximum net photosynthetic rate at 12pm, is obtained. And the reason why prunus persica cultivated in heliogreenhouse gives lower net photosynthetic rate in a fine day at 12.00pm is the shortage of CO2.the major environmental factors are favorable when the concentration of CO2is no less than 310.1ul/L, the temperature is 21.0C-32.5C and the relative humidity is no lower than 45.3%. In accordance with the variation law of major meteorological factrors and their effects to the photosynthesis of prutus cultivated in heliogreenhouse, the technical measures for cultivating prunus persica in heliogreenhouse have been suggested... |
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