| With the increasing frequency of industrial and agricultural activities,heavy metal pollution has gradually entered people’s vision and received attention.Cadmium pollution is the most common type of heavy metal pollution and is more harmful to plant growth.Soybeans are an important crop,and the stable development of the soybean industry is of great significance to China’s agricultural production.Soil cadmium pollution has different degrees of influence on the growth,development and yield of soybeans.The results show that wild soybeans have good genetic diversity,especially good resistance to stress,which is of great significance for broadening the resources of soybean stress resistance breeding.In this study,wild soybeans,semi-wild soybeans and cultivated soybeans with different cadmium sensitivities were selected as test materials,and the changes and differences of morphology,physiology and yield of different types of soybeans under cadmium stress were studied,which provided a scientific basis for the development and utilization of cadmium-resistant multiplasm resources of soybeans.The main findings are as follows::1.Morphological studies at different developmental stages showed that compared with the control,cadmium stress had obvious inhibitory effects on plant height,stem thickness and root growth of LD11 at different developmental stages,while the inhibition effect on TF31 was only obvious at the seedling stage and the pod stage,and only the total root volume was inhibited in root growth;the inhibition effect on BY41 plant height was only obvious at the seedling stage,and the inhibition effect on by BY52 plant height and stem thickness at the pod stage and maturity stage.The total root volume and root surface area of the two semi-wild soybeans had obvious inhibition effects,and the total root length of BY52 was also significantly lower than that of the control;there was no obvious inhibition effect on the height and stem thickness of Y1 plant,but it had obvious promotion effects at the pod stage and maturity stage,and also had obvious promotion effects on root surface area,total root volume and total root length,and had obvious inhibitory effects on the plant height of Y18 at different developmental stages.From the morphological comprehensive resistance index,the ranking from largest to smallest is wild soybean> semi-wild soybean > cultivated soybean.2.Photosynthesis studies at different developmental stages showed that cadmium stress only increased the seedling transpiration rate of wild soybean Y1 compared with the control,and the photosynthetic parameters of other periods and other varieties at different times were inhibited or had no obvious promotion effect.There was little difference within the type of inhibition of the two cultivated soybeans,while the response to cadmium stress was even greater within the wild soybean and semi-wild soybean types.According to the composite resistance index,two wild soybeans are higher than other cultivated soybeans and semi-wild wild soybeans,BY41 is higher than two cultivated soybeans,but BY52 is lower than two cultivated soybeans,Y1 is the highest,and BY52 is the lowest.3.Antioxidant enzyme and MDA studies at different developmental stages showed that cadmium stress increased the SOD activity of wild soybeans compared with the control compared with the control,and the SOD activity of wild soybeans was still significantly higher than that of the control at the maturity stage,while the SOD activity of cultivated soybeans and semi-wild soybeans was inhibited;the activity of PODs at the seedling stage and semi-wild soybeans was higher than that of wild soybeans and semi-wild soybeans,but the POD activity of cultivated soybeans was significantly lower than that of controls at maturity.The POD activity of semi-wild soybeans was not significantly inhibited,and the wild soybeans were significantly higher than the control;the CAT activity of the two cultivated soybeans at the seedling stage was significantly higher than that of the control,while the two semi-wild soybeans were significantly lower than the control at the pod stage and the mature stage,and only Y1 in the wild soybeans was higher than the control at the seedling stage and the podbearing stage;the MDA content of the two cultivated soybeans in different periods was significantly higher than that of the control,and only BY52 and Y18 were higher than the control at the mature stage in wild soybeans and semi-wild soybeans.The comprehensive resistance index shows that the three comprehensive resistance indexes of soybeans,from largest to smallest,are wild soybeans> cultivated soybeans> semi-wild soybeans.4.The results of soybean yield traits showed that compared with the control,the single plant stem weight,single plant pod weight,single plant grain count and single plant grain weight of the two cultivated soybeans under cadmium stress were significantly lower than those of the control,and the hundred grain weight of TF31 was also significantly reduced;the stem weight of the two semi-wild soybeans was significantly reduced,and the single plant grain number and single plant grain weight of BY52 were also significantly lower than the control;the single plant stem weight and single plant grain number of Y1 under cadmium stress were significantly higher than the control,but the 100 grain weight was significantly reduced,and the single plant stem weight,single plant pod weight,and single plant grain weight of Y18 were significantly lower.According to the comprehensive resistance index,wild soybean Y1 is the highest,cultivated soybean LD11 is the lowest,and wild soybean and semi-wild soybean are higher than cultivated soybean.5.Studies on the cadmium content of soybeans show that the cadmium content of different types of soybean roots is higher than that of stems,leaves,pods and grains;from the perspective of the difference in cadmium content of different types of soybeans,the difference between the two wild soybeans is the largest,Y18 has the highest cadmium content in each part,followed by semi-wild soybeans,and the difference in cultivated soybeans is the smallest;from the perspective of the difference in cadmium content in different parts,the cadmium content of different parts of cultivated soybeans is from more to less,which is the root > leaf > pods,and the cadmium content of stems and grains is low,of which the cadmium content of TF31 grains is lower than that of the stem.LD11 grain cadmium content is higher than the stem;semi-wild soybean and wild soybean both show root > stem > leaf > grain > pod;from the perspective of different site transport coefficients under cadmium stress,the TF root-stem of soybean is lower than the transshipment coefficient between other parts;from the perspective of different types of soybeans,two semi-wild soybean TF root-stem are the highest,the TF pod-grain of the two kinds of wild soybeans is the highest,and for TF pod-leaf,both cultivated soybeans and semiwild soybeans are higher than wild soybeans. |
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