| In order to improve the germination rate of pecan and reduce germination time,the paper studied the effects of seed shelling treatment,water soaking time,and germination temperature on seed germination.Sowing the seeds after germinating at different temperatures,measuring the indicators of seedling growth and development,and exploring the effects of different germinating temperatures on seedling growth and photosynthetic characteristics.For produce more sexual seedlings,the author probe to produce two seedlings from one seed.The main results are as follows:(1)Seed shell breaking and shell removal treatment shows that seeds of the shell-breaking treatment reached 84% of the final water absorption rate on the 3rd day,while the complete seeds only reached 82% of the maximum water absorption rate on the8 th day,indicating that the seed shell has certain water permeability.On the 7th day,the respiration rate of the broken shell seeds was significantly higher than that of the intact seeds,indicating that the thin-shelled pecan seed shells have barriers to ventilation.(2)The effects of seed soaking time on seed germination indicated thatwithin a certain soaking time range,the longer the soaking time,the higher the seed germination potential,but the final germination rate difference was not significant(3)The results of treat seeds with 5 electro thermal germination of 20℃,25℃,30℃,35℃,40℃,showed that after 14 days of germination,the germination rate at 30℃ was the highest in the treatment room,reaching 94.29%,higher than 85.14% at 40℃,89.82%at 35 ℃,80.31% at 25℃,78.18% at 20℃,or 30℃> 35℃> 40℃> 25℃> 20℃.(4)Different germination temperatures also have different effects on seedling growth and photosynthetic characteristics.The measurement of seedling growth and photosynthesis characteristics found that when the germination temperature was 30℃,the growth and photosynthesis of seedlings were significantly improved.(5)Experimental studies on different irrigation methods show:The bottom irrigation could significantly increase the seedling’s ground diameter,seedling height and root length than the upper irrigation seedlings.The photosynthetic characteristics were the same.This showed that bottom irrigation can improve the quality of seedlings.(6)Two batches of seedlings will appear after the seedlings wererooted in the "one seed produce two seedlings" nursery pond by comparing the growth and photosynthesis indexes of the two batches of seedlings.The main root length and seedling height of the upper layer seedlings were not significantly different from those of the lower layerseedlings.The ground diameter was significantly different from that of the lower layer seedlings.The ground diameter of the lower layer seedlings was reduced by 20%compared with the upper layer seedlings.The leaf SPAD values and photosynthetic characteristics of upper and lower seedlings were not significantly different from those of root and tiller seedlings.(7)The economic benefits of the "one seed makingtwo seedlings" cukturaltechnology were analyzed.The results showed that the "one seed making two seedlings" nursery technology had a better effect of increasing income and saving expenditure.The paperprovide a basis for the promotion of the technical system. |
