Effects Of Sub-Low Temperature On Growth And Products Of Cucumber In Greenhouse

As the tremendous energy pressure of optimal temperature in greenhouse's production from the 1990s, the world vegetable's production of greenhouse are introduced sub-low temperature (sub-optimal temperature regime) planting new strategy to save energy. In this paper, cucumber (Cucumis sativus L.), one of the main vegetables grown in the modern greenhouse was used as the experimental material. The test was given optimal and sub- low temperature regimes, and source-sink regulation was made under sub-low temperature. Changes in plant height, leaf area, photosynthesis and chlorophyll content, and on fresh and dry weight of root, stem, leaf and fruit and production, and on total dry matter accumulation and root, stem, leaf and fruit dry matter distribution rate, and on content of total soluble sugar, sucrose, fructose and glucose of cucumber in greenhouse were investigated both in sub- low temperature and optimal temperature. The results showed as follows:â… Plant height, leaf area, dry and fresh weight of stem and leaf of cucumber were lower under sub- low temperature than that under optimal temperature. The number and fresh and dry weights of fruits of Dai Duoxin,22-51 and 22-39 at 128 d showed higher under sub-low temperature regime.â…¡Total dry matter accumulation and root, stem, leaf and fruit dry matter distribution rate of cucumber under two temperature treatments increased with the planting days but root, stem, leaf and fruit dry matter distribution rate decreased. The difference of total dry matter accumulation and root dry matter distribution rate of cucumber weren't evident. Dry stem matter distribution rate was lower under sub- low temperature. While the numbers and products of fruit were on the contrary.â…¢Total sugar content, and sucrose, fructose and glucose content of the five varieties under two temperature treatments, reached to the highest at 94 d. Contents of total soluble sugar, and sucrose, fructose and glucose content were higher under sub- low temperature than that of optimal temperature treatment or had no significant differences under two temperature regimes. This suggested that cucumber grow normally under sub-low temperature.â…£In the test of remaining different fruit numbers with five treatments, fruit numbers and dry fruit matter partitioning rate ascended with the reduction of remaining fruits. However, chlorophyll content, leaf area, plant height, total sugar content, dry root matter distribution rate, dry stem matter distribution rate and leaf dry matter distribution rate of cucumber increased gradually.â…¤In the test of remaining different leaf numbers with four treatments , leaf area, fruit numbers, total sugar content, dry leaf matter distribution rate and dry root matter distribution rate of cucumber ascended, but dry fruit matter distribution rate and dry stem matter distribution rate increased gradually with the reduction of remaining leaves.â…¥In the test of remaining different fruit numbers of five treatments , the difference on content of total soluble sugar of five treatments was not obvious. The results showed that there was no significant effect of sub-low temperature on total sugar content but had some effects on sucrose, fructose and glucose content when there was less numbers of fruits remaining on plants. In the test of different leaf numbers, contents of various sugars measured were higher when 80â„… numbers of leaves remaining.