Effects Of Artificial Aging And Seed Priming On Seed Physiological Characteristic Of Pyrus Betulaefolia Bge.

Pyrus betulaefolia Bge,was a pioneer species for desertification in northwest China and it was widely used in the northern region as a good stock for cultivated pear and landscaped trees,which had high utilization value and prospect.It mainly relied on seeding to breed which accompanied by low germination rate and there was little research on its seeds.In order to obtain the methods for promoting seeds germination and improving seed vigor,the effects of artificial aging and seed priming on the seed vigor and physiological and biochemical characteristics of seeds were studied.The results were as follows:(1)With the increase of aging time,The tendency of the germination rate and germination potential of seeds increased and then decreased,and the germination rate of the two days was the highest,reaching 46.67 ± 1.96%.It was showed that a short period of high hot and humid conditions could improve seed vigor;The activity of SOD,POD,CAT and APX decreased after initial a slight increase.The activity of APX was the most sensitive to aging.The relative electric conductivity,the content of soluble sugar and MDA increased,and the content of soluble protein decreased continuously.The intensified membrane peroxidation was the importance reason of aging.(2)The effects of treatments were different,and were affected by itself.The same aging Pyrus betulaefolia Bge seeds with the concentration of PEG or salicylic acid increased,the germination rate and vigor index increased first and then decreased,but with the concentration of calcium chloride increased,the germination rate and vigor index increased.Seed priming in this study had different effect on the germination rate with different aging seeds.The effects of treatments significantly on aging 3～4 days of seeds,for seeds aging 0～2 days had no significant effect.(3)The effect of 30%calcium chloride concentration was the best.The treatment with calcium chloride could promote the germination of Pyrus betulaefolia Bge seeds.the aging 4 days of seed was most significant,germination rate increased from 11.33±0.54%to 33.33±1.09%,increased by 194.17%.(4)The treatments with PEG and calcium chloride could effectively improve the activity of POD,APX and SOD,and with salicylic acid could increase the activity of POD and APX in seeds.With treatments in this study,the content of MDA and relative conductivity decreased,the content of soluble sugar and soluble protein significantly increased.It showed that with the treatments of seeds priming,the membrane lipid peroxidation could be effectively slowed down and a certain degree of seed vigor restoration could be achieved.(5)The seeds with aging two days had a significant effect on seed germination rate,reached 46.67±1.96%,however the seeds with seeds priming had no significant difference with same aging seeds on germination rate,vigor index.For the newly harvested Pyrus betulaefolia Bge seeds,aging treatment may play a decisive role.Short term artificial aging could effectively improve seed vigor and achieve better germination effect for new mining seeds.