Research On Photosynthesis Of Blueberry Grown In Greenhouse Plastic House And Open Field

Photosynthesis is one of most important physiological processes in fruit tree. The carbohydrate which is formed through photosynthesis is the main material base to form the output, so it is of great significance to study the fruit tree's photosynthesis in order to reveal the law of output formation. In facility cultivation conditions, the cover, the variation of environmental factors etc. affect the growth and photosynthesis of fruit tree. It has the important theoretical and practical significance in studying the blueberry photosynthesis in different cultivation pattern which is not only helpful to the establishment of good quality and high output cultivation pattern, but also meaningful to investigate the physiological reaction of blueberry in different cultivation pattern.The trials were conducted from May 2004 to November 2005 at the berry orchard of Jilin Agricultural University. 'Bluecrop' and 'St. Cloud' were selected as trial materials. The soil was composed of peat, manure and raw soil with the ratio of 1:1:1, and S powder was mixed in order to reform the soil. TPS-1photosynthesis measurement system was used to investigate the blueberry leaf's photosynthetic characteristics. At the same time, comparison was made among 17 varieties besides 'Bluecrop'. The main results were as follows:1. The curves of diurnal change of Pn in 'Bluecrop' and 'St. Cloud' were both bimodal curve, and there were obvious 'midday rest' phenomenon. Except the 'Blue crop' grown in open field ascended the highest peak at 6 a.m., all treatments of both cultivars arrived at the highest peak in whole day at 8 a.m. The highest Pn of 'Bluecrop' in three cultivation pattern (greenhouse, plastic house and open field) were9.64 μCO₂mol · m^-2 · s^-1,8.8 μCO₂mol · m^-2 ·s^-1 and 6.95 μCO₂mol · m^-2· s^-1. Pn of 'St. Cloud' were 11.38 μCO₂mol · m^-2 · s^-1, 9.03 μCO₂mol· m^-2 · s^-1 and 8.26 μCO₂mol · m^-2 · s^-1.2. Double peaks appeared in the curve of seasonal variation of leaf Pn in 'Blue crop' and 'St. cloud', with the first peak appearing in early June and the second peak in early September, and the second peak was the highest in the whole year. The annual highest Pn of 'Bluecrop' were 7.925 μCO₂mol · m^-2· s^-1, 9.6 μCO₂mol · m^-1 · s^-1, 10.62 μCO₂mol· m^-2 · s^-1 respectively; 'St. Cloud' 9.13 μCO₂mol· m^-2 · s^-1, 9.95 μCO₂ mol · m^-2 · s^-1, 10.92 μCO₂mol · m^-1 · s^-1 respectively.3. Pn-PAR curve was a hyperbold. In a certain range with the PAR increasing, the Pn increased. Facility cultivation reduced the two cultivars leaves LSP and LCP. LSP of 'Blue crop' in three cultivation pattern (greenhouse, plastic house and open field) were 802.5 μmol · m^-2 · s^-1,762.5 μmol · m^-2 · s^-1, 887.5 μmol · m^-2 · s^-1 and LCP were 53.89 μmol · m^-2 · s^-1, 80.82 μmol · m^-2 · s^-1,58.81 μmol · m^-1 · s^-1;LSP of 'St. cloud' were 672.5 μmol · m^-2· s^-1,755 μmol · m^-2· s^-1,817.5 μmol · m^-2· s^-1 and LCP were 53.66 μmol · m^-2· s^-1,62.77 μmol · m^-2· s^-1,96.59 μmol · m^-2· s^-1.4. Pn and low concentration of CO₂ were remarkable positive beeline correlation. CCP of 'Bluecrop' in three cultivation pattern (greenhouse, plastic house and open field) were 163.27 μmol · mol^-1, 100.98 μmol · mol^-1, 119.17 μmol · mol^-1, CCP of 'St. Cloud' were 95.71 μmol · mol^-1, 86.61 μmol · mol^-1,...