Studies On The Characteristics Of Growth Development And Physiology Of Seedling Raising With Soilless-Substrate And Root-Naked Transplanting Cotton (Gossypium Hirsutum L.)

The purpose of experiment was to study the effects of SRSRT, the new technique of cotton (Gossypium hirsutum L.) planting. Field experiments were located in Dongchang test station of Cotton Reasearch Institute, Chinese Academy of Agricultural Sciences in Anyang city, Henan province (N36°07', E114°22') in 2006, with loam soil of moderate fertlities in experimental field. The test was repeated 3 times by designing 3 treatments including SRSRT, SRTNS and DS, in which randomized block design was used and two hybrid anti-bollworn cotton varieties ('CRI46' and 'CRI29' ) were presented to study the characteristics of growth development, lint yield, fibre quality and physiology of SRSRT cotton planted in single cropping system and double cropping system of wheat-cotton with "3-2" row planting pattern, contrasted with SRTNS cotton and DS cotton. The results were as follows:1. The total growth period of SRSRT cotton was longer than SRTNS cotton and DS cotton. The time of SRSRT cotton from transplantation to squaring stage and from squaring stage to boll opening stage was about 5 to 6 days and 3 to 4 days longer than that of SRTNS cotton respectively. The time from squaring stage to boll opening stage was approximate between SRSRT cotton and DS cotton.2. The growth of main stem of SRSRT cotton was faster at the period from squaring stage to full-bloom and boll-forming stage than that of SRTNS cotton and DS cotton. The increased dry weight per day per plant of SRSRT cotton from flowering stage to boll opening stage was more than that of SRTNS cotton and DS cotton. In single cropping system, the development of leaf area per plant of SRSRT cotton from squaring stage to boll opening stage was faster than that of SRTNS cotton and DS cotton, and the RM/OM of SRSRT cotton at early-blooming stage and full-bloom stage was higher, too.3. In single cropping system, the seed cotton yield of SRSRT cotton was higher than that of SRTNS cotton and DS cotton with significant difference between SRSRT cotton and DS cotton, while there were no difference between SRSRT cotton and SRTNS cotton., the lint yield of SRSRT cotton was lower than that of SRTNS cotton and higher than that of DS cotton with significant difference between SRSRT cotton and DS cotton, while there were no difference between SRSRT cotton and SRTNS cotton. In wheat-coton double cropping system, the seed cotton yield and lint yield of SRSRT cotton were higher than that of SRTNS cotton and lower than that of DS cotton with significant difference between SRSRT cotton and SRTNS cotton, while there were no difference between SRSRT cotton and DS cotton.4. Root Growth Promoting Agent (RGPA) had apparent effects in the regulation of rooting in seedling beds of substrate and lateral root development after transplanting. Lateral roots of SRSRT cotton grew actinomorphicly to all sides like the surface of an umbrella, in which there were about 6 to 8 dominant strong lateral roots with diameter width wider than others. Lateral roots of SRTNS cotton spread anisomerously to one side like the paw of a chicken, in which there were about 1 to 2 or 2 to 3 dominant lateral roots. The root system of DS cotton was representative taproot system.5. The photosynthetic rate, stomatal conductance and transpiration of SRSRT cotton functional leaves were higher than those of SRTNS cotton and DS cotton at squaring stage as well as blooming stage in single cropping system and squaring stage as well as peak boll period in double cropping system of wheat-cotton.6. SOD, POD and CAT activity in functional leaves of SRSRT cotton varied similar to those of SRTNS cotton and DS cotton during whole growth period. SOD activity in functional leaves of SRSRT cotton was higher at preceding periods as well as latter periods and lower at middle periods, while POD activity was lower at preceding periods as well as steady at middle periods and higher at latter periods, CAT activity was lower at preceding periods as well as latter periods and higher at middle periods. MDA contents in functional leaves of SRSRT cotton varied approximately similar to that of SRTNS cotton and DS cotton. MDA content of functional leaves of SRSRT cotton was higher than that of SRTNS cotton and DS cotton before and after growing alive.7. Total nitrogen contents and total phosphorus contents in functional leaves of SRSRT cotton were approximately equal to those of SRTNS cotton and DS cotton at different periods and varied similar to those of SRTNS cotton and DS cotton during whole growth period. Total potassium contents in functional leaves of SRSRT cotton were significant higher than that of SRTNS cotton and DS cotton from July to August.