Variation Of The Major Ecological Factors And The Relationship With Yield Formation Of Cucumber In Sunk Solar-greenhouse

Changes of major ecological factors in sunk and ground solar-greenhouses in Shouguang were investigated from Sep. 2009 to May. 2010. The diurnal variation of photosynthetic rate (Pn), photosynthetic efficiency, fluorescence parameters, and the rules of growth and yield formation of cucumber in sund and ground solar-greenhouses studied. The results are as follows:1. The air temperature (Ta) in day and night changes from 15.3℃to 40.6℃(from Sep. to next May.), and soil temperature (Ts) was 19.0²5.0℃in sunny condition.Ta and Ts in Jan.were the lowest, and May the highest among the measurement stage. The air relative humidity (RH) in sunk solar-greenhouse was changed from 42.6 % to 97.7 %, and highest in Jan., lowest in May.. Ta changed with the similar rule to Ts in day and night. Ta came to the lowest at 5:30⁷:30, and to the highest at 12:00¹3:30.The lowest and highest value of Ts appeared at 8:30¹0:30 and 17:30²0:00 respectively. RH in day and night changed contrary to Ta, its lowest value appeared at 12:00¹5:00, and the highest one appeared at 7:00⁹:00. The photon flux density (PFD) changed from 211.0μmol·m^-2·s^-1 to 1304.7μmol·m^-2·s^-1, and CO₂ concentration was 207¹219μl/L in the measurement stage. The PFD increased in the morning, while decreased in the afternoon. But the CO₂ concentration was changed oppositely. Their peaks or valleys appeared at 11:00¹4:00. Compared with ground solar-greenhouse, the sunk one showed a increase in Ta, Ts and RH, and no significant differences in PFD and CO₂. The time of higher than 35℃in Ta, and 90 % in RH in sunk solar-greenhouse were longer than those of in ground one, whereas the time of lower than 20℃in Ta and 70 % in RH in sunk solar-greenhouse were shorter than those of ground one.2. The diurnal variation of Pn showed the same patterns between cucumber leaves in sunk and in ground solar-greenhous. They presented double-peak carves which peaks appeared at 11:00 and 13:00 in Sep., and single-peak carves which the peak appeared at 12:00 in other months. From Sep. to the next May., the peak volume of Pn were the highest in Nov. and March., the second in May. is, and the lowest in Jan. The Pn of cucumber leaves in sunk solar-greenhous were higher than that in ground solar-greenhouse in most of months.3. The carboxylation efficiency (CE) and apparent quantum yield (AQY) of cucumber leaves in solar-greenhouse were decreasing in autume-winter, and increasing in winter-spring. The CE was remarkable higher in sunk greenhouse than that in ground solar-greenhouse. No significant difference in AQY was found between cucumber leaves in sunk and in ground solar-greenhous.4. The actual photochemical efficiency (φPSâ…¡) in luminance was the lowest in May, and had no differences amoung other months. Little changes were found in the maximal photochemical efficiency of PSâ…¡in darkness (Fv/Fm) and initial fluorescence at different stage. Cucumber in sunk solar-greenhouse showed a significant increase inφPSâ…¡in Nov., Jan., and March, compared with that in ground solar-greenhouse. No distinct differeces were found inφPSâ…¡, Fv/Fm, and Fo between plants growth in sunk and ground solar-greenhouse in Sep. and May. No photoinhibition was occurred during growth and development stage of cucumber plants.5. The daily increase of plant height and leaf numbers were decreasing, friuts/ leaves ratio was increasing, as time goes on in autumn-winter. From blomming to market ripening of friuts, there need 5.7 to 8.9 days. In winter-spring, little change was observed in plant height. The daily increase in leaf number was larger in Jan., while that in other months was less. The friuts/leaves ratio was increasing as time goes on, and the friut ripenning time was about 5.8¹1.1 day. The cucumber showed an increase in growth and development rate, friut/ ratio and ripenning rate in sund solar-greenhouse, and total yield, compared with that in ground solar-greenhouse.