| Since the floating nursing seedling in nutrient water-bed (FNSNWB) was developed, it has achieved and applied quickly. After transplanting the cotton seedlings from FNSNWB, the cotton plant has many advantages with low cost, high efficiency, labor-saving and yield increasing. In order to elucidate the biological base for transplanting the cotton seedlings from FNSNWB with high yield and efficiency and provide theoretic foundation for spreading the technology of FNSNWB. The cultivar Jinnong 1 was used as the materials to be investigated the plant performance in the field from seedling to boll opening stages at morphological and physiological-biochemical levels in the present paper.1 Morphology of root system and yield for the FNSNWB cotton plant(1) After transplanting, the roots grew quickly and recover period of them was short. The seeding of FNSNWB need 8 days to regrow,3-5 days less than the control which were used the method of nutritive bowls nursing seedling (NBNS, control), the From the 8th day after transplanting, the fresh and dry weight of roots, root length, main root length, root/shoot ratio, root area, the first and second lateral roots were increased, but the control was later which started to grow in the 12th day after transplanting.(2) The experiments showed that the roots of seedling cultivated by FNSNWB developed greater than the control. The dry weight of roots, main root length, root/shoot ratio, radius of root, the first and second lateral roots were much more than control. Meanwhile, the fresh weight of roots, root length, root areas were also much more than control. From squaring to boll opening stage, the fresh weight of roots increased 5.24 g,6.17g,7.05g,8.21g and 7.35g, respectively. The root length increased by 28.88%,14.57%,18.64%,19.24% and 19.65%, respectively. The root area increased 78.15cm2,103.82cm2,124.89cm2,115.61cm2 and 116.86cm2, respectively.(3) Compare with NBNS, the yield enhanced significantly using FNSNWB. The fruiting branches were 20.7 in average,2 to 3 more than the control. The boll retention was 66.6 and increased by 24.02%. The squares and bolls shedding were 45.3%, it was 2.6% lower than that of the control. The yield of cotton transplants with FNSNWB in the field was 2039 kg·hm-2,144.0 kg·hm-2 more than the control.2 Analysis of physiological and biochemical characteristics of cotton transplants by FNSNWB(1) The physiological activities of the root by FNSNWB was higher in the period recovery. The experiments show that the TTC reductive intensity was reactivate in root system in the 8th days after transplanting, which was 3 days earlier than control. Meanwhile, superoxide dismutase (SOD), peroxidase (POD) activities and catalase(CAT) in cotton roots by FNSNWB were all higher than that of the NBNS, but the malondialdehyde (MDA) contents were obviously lower than that of the NBNS, which was 63.86%,37.14%,74.42%,51.85% and 43.62%, respectively. For the reason of the higher physiological activities, the root grew quickly, so the recovery period of the seeding was shorten.(2) The experiments showed that the TTC reductive intensity, the activities of SOD, POD and CAT in root system from squaring to boll opening stage were obviously higher than that of the NBNS. Among them, the TTC reductive intensity was 12.84%,12.68%,11.89%,11.58% and 87.99% higher, respectively, the activities of SOD was 37.61%,12.36%,5.55%,55.80% and 12.22% greater, respectively. The activities of POD increased by 19.12%,24.16%,11.93%,11.04% and 6.37% respectively. The activities of CAT were 18.58%,10.99%,20.98%,76.04% and 79.89% higher, respectively. (3) From seedling to boll setting stage, the contents of N, P and K in plant roots were higher than that of control. From seedling to full bloom stage, the contents of N increased by 17.74%,25.36%,40.52%,39.81%,50.69%,17.02%,24.47% and 22.72% respectively and the difference was significant. Compared with the transplants by NBNS, the contents of N and P in cotton root were higher, but the content of K was lower than the control in boll opening stage. Therefore, the higher absorption efficiency of nutrient is to provide nutritional foundation for the higher yield. s... |
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