Comparison of Root Morphological and Activity of Representative Soybean Cultivars (MG III) Developed in the USA and China
Objective]The research was compared on the root morphological and activity of soybeans [Glycinemax (L.) Merr.] developed in different years from the different breeding programs of Ohio, USA, and Liaoning, China, which were at the same latitude. The purpose of this study was to reveal the evolutionary trend of root traits, and the response to the fertilizer rate with the improvement of seed yield.[Method] The pot experiment was conducted in 2012 and 2013, and used a completely randomized design with three replications, and all used cultivars had the same ancestors (Williams and Amsoy). The diammonium phosphate was applied at the seedling stage (V2) with a solution condition, and had three levels (0, 150, and 300 mg·kg-1dry soil). The plants were cut at the cotyledonary node at the stages of V4, R2, R6, and R7, and the root bleeding sap weight was measured by a weight difference method with absorbent cotton suction. The plant root was scanned by an Epson Expression 10000XL, and then WinRhizo2012 software analyzed the scanning images to determine root length, root surface area, and number of root hairs, and the root activity was measured by a triphenyl tetrazolium chloride method (TTC). The root samples were dried in the oven at 105?C for 30 minutes and at 80℃ at least for 72 hours to achieve a constant weight, and the seed yield per plant was measured at the mature stage.[Result] The root length, root surface area, number of root hairs, root dry weight, root bleeding sap weight, and root activity of Ohio and Liaoning cultivars had the same improvement trend, and all of those were increased with the yield improvement, especially at the stage of R6 and R7, and the value of root morphological and activity was increased greatly by years. Compared with the cultivars of different regions, the root length, the improvement progress of root surface area, the number of root hairs, the root bleeding sap weight, and the root activity of Ohio cultivars was better than the Liaoning cultivars. With the increasing of fertilization rates, the root traits value of the current cultivars of Ohio and Liaoning showed very well at both the medium (150 mg·kg-1dry soil) and high (300 mg·kg-1dry soil) fertilization levels, and those of the middle cultivars of two regions were best at the medium fertilization rate. Under the same fertilizer rate, the root traits value of current cultivars was greater than the ancestor and middle cultivars. The results of correlation and path-coefficient showed that root length, root surface area, root dry weight, root bleeding sap weight, and root activity had significant positive correction with the seed yield per plant at the stages of V4, R2, R6, and R7, and that the correction between root activity and seed yield per plant was the best.[Conclusion]During the improvement of the soybean yield of the Ohio and Liaoning cultivars, the root morphological and activity had the same improvement trend, and the root length, root surface area, root bleeding sap weight, and root activity were increased with the yield improvement, but the improvement progress of Ohio cultivars was greater than that of Liaoning cultivars. Fertilizer tolerance was enhanced in both Ohio and Liaoning cultivars, the root traits values of current cultivars of two regions showed very well at both the medium (150 mg·kg-1dry soil) and high (300 mg·kg-1dry soil) fertilization levels, and that of the middle cultivars were best at the medium fertilization rate.
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万方数据
维普
