Effects of 6-Benzylaminopurine on internal water distribution and growth state of soybean

Soybean sprout is one type of edible vegetable that is cultivated by sprouting soybeans. Taking Zhonghuang 13 as the research object, a series of treatments were carried out using the 6-BA solution with concentrations of 0, 1, 3, 5, 7, and 9 mg/L under the same environmental conditions. The water distribution in soybean was measured to determine the growth state under the different concentrations of 6-BA during soybean germination. The low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) were selected to clarify the effect of 6-BA on the germination of soybean. Three procedures included the LF-NMR, LF-NMR/MRI imaging, and the acquirement of soybean physical, chemical, and morphological indexes. The proton density (PD) image was extracted from the nuclear magnetic signals collected by the Carr-Purcell-Meiboom-Gill (CPMG) spin echo pulse sequence. The results show that the water evolution was visually determined during soybean germination using the LF-NMR PD images. The soybean germination was divided into the imbibition (0-8 h), protrusion (8-24 h), and germination stage (24-60 h). The germination cycle from the soaking to germination varied with the concentration of 6-BA solution in the treatment groups. The germination time of soybean seeds with the 0, 1, and 3 mg/L of 6-BA solution was shorter than that of the rest, where the best was the 3 mg/L concentration. The water content in various phases of soybean was quantitatively characterized by LF-NMR data. According to the relaxation time, the water content of soybean was divided into three kinds: the bound water T21, semi bound water T22, and free water T23. The sub peak was disappeared gradually on the left side of bound water (0.1 ms