| Soilless-substrate naked-seedling and transplanting(SSNST), is a main simplified increasing yield and efficiency cotton cultivation technology, adapts to the development of agriculture, and has been spread by the department of agriculture in China. Several rate and recovering stage are key factors to test transplant technology. Therefore we study the response of soilless-substrate naked-seedling and transplanted cotton growth on temperature to different seedling raising manners at seedling recovering stage. We conducted laboratory experiment and pot experiment respectively. The pot experiment was conducted to research the impact of temperature to seedling raising manners on cotton root growth. Two treatments (open cultivation and plastic tunnel) were included in this experiment, in order to surveyed survival rate of plug seedling and naked-root seedling, and determined root growth and physical indicators in recovering stage The laboratory experiment was conducted to study the effect of different temperature of15℃,27℃and37℃on antioxidant enzyme activities and other physical indicators during recovering stage. Results as follow:(1) The pot experiment showed that, the survival rates of4treatments were all100%, but they took different time to pass recovering stage. The experiment conducted in May showed that recovering stage time of open cultivation and bare-root transplant, plastic tunnel and root-naked seedling transplant and open cultivation and plug seedling transplant were respectively10d,8d,8d and7d. The experiment conducted in September showed that recovering stage time of open cultivation and bare-root transplant, plastic tunnel and root-naked seedling transplant and open cultivation and plug seedling transplant were respectively9d,9d,7d and6d. Plastic tunnel and plug seedling transplant Plug seedling took shorter time than naked-root seedling, and plastic tunnel took shorter time than open cultivation in general.(2) The pot experiment showed that chlorophyll content and root vigor of4treatments were all firstly going up, and then descending with growing process. In general, the4treatments showed that root-naked seedling was higher than plug seedling, open cultivation was higher than plastic tunnel. The laboratory experiment showed that root vigor of cotton seedling under three temperature treatments were all going up at first, and then descending with growing process. While maximum value of root vigor were different, root vigor of27℃were higher than that of37℃, and root vigor of15℃was lowest. There was no significant impact in chlorophyll content of cotton seedling under27℃and37℃conditions in laboratory experiment. However, the temperature of15℃had a huge influence on chlorophyll content of cotton seedling, and the chlorophyll content raise quickly after seedling transplanted.(3) The pot experiment showed that the change tendency of root MDA content showed firstly going up, and then descending with growing process. In general, root MDA content for4treatments showed that root-naked seedling was higher than plug seedling, open cultivation was higher than plastic tunnel. MDA content of cotton seedling leaves under three temperature treatments were all going up at first, and then descending in laboratory experiment. MDA content of cotton seedling leaves under15℃was apparently higher than that of27℃and37℃.(4) The pot experiment showed that except plastic was higher than open cultivation, POD and CAT activities showed the same variation trends with MDA, firstly going up, and then descending with growing process. The laboratory experiment showed that POD and CAT activities of three treatments showed similarity tendency, they were all going up, and then descending.(5) The pot experiment showed that plastic tunnel increased soil temperature. The surface temperature increased significantly, jet the temperature of5cm and10cm increased little. Fresh weight and dry weight per plant, root dry weight, leaf area per plant and root growing parameters (root length, root diameter and root superficial area) were all increasing with growing process. No significant difference was obtained in4treatments at early time, and they had significant difference at later time. Those index of plug seedling higher than those of naked-root seedling, and those index of plastic tunnel were greater than those of plastic tunnel open cultivation. |
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