ISHS Acta Horticulturae 633: XXVI International Horticultural Congress: Protected Cultivation 2002: In Search of Structures, Systems and Plant Materials for Sustainable Greenhouse Production
CO2 ENVIRONMENT IN SOLAR GREENHOUSE IN NORTHERN CHINA AND EFFECTS OF CO2 ENRICHMENT ON PHOTOSYNTHETIC RATE AND DRY MATTER PRODUCTION OF CUCUMBER |
| Authors: | M. Wei, Y. Xing, X. Wang, H. Ma |
| Keywords: | CO2 concentration, CO2 depletion, photosynthesis, dry matter weight, vigorous seedling index |
| Abstract:
The lean-to solar greenhouse is one of the main forms for protected spring-winter cultivation in northern China. Three experiments were conducted to investigate the variation of CO2 concentration and to assess the effect of CO2 enrichment on the photosynthetic rate (Pn) and on dry matter yield of cucumber (Cucumis sativus L.) in a solar greenhouse. Daily maximum concentration of CO2 decreased gradually from November to the following May, while daily minimum and mean concentrations dropped from November to January and from November to March respectively, and then both went up. Depletion of CO2 occurred 3.1 hours after unveiling in the morning and lasted for approximately 4.0 hours in December, whereas it moved up to 1.1 hours after morning unveiling and the period extended to 8.0 hours the following March. The solar greenhouse often showed severe CO2 depletion before and after ventilation during the daytime. Photosynthetic rates of cucumber at fruiting stage with CO2 enrichment were 110-175% (morning, 780-1215/280 μl L-1) and 80% (afternoon, 500-700/250 μl L-1) higher than that of non-enriched plants. Cucumbers at seedling stage with CO2 enrichment in the morning and in the afternoon at the level of 1100 ± 100 μl L-1 produced 68.08% or 259% more plant dry matter than that with CO2 enrichment in the morning only or without enrichment. Plants with CO2 enrichment in the morning also only yielded 113.85% more dry matter than that of non-enriched plants. It is concluded that CO2 enrichment in the morning and in the afternoon enhanced photosynthesis and promoted growth of solar greenhouse-grown cucumber. | |
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