不同浓度亚硒酸钠溶液对水杉种子萌发的影响

Influences of different sodium selenite concentrations on seed germination of Metasequoia glyptostroboides

关键词:  水杉种子, 亚硒酸钠浓度, 萌发

Key words:  Metasequoia glyptostroboides seed, sodium selenite concentration, germination

摘要:

硒元素是植物生长所需的微量元素。在水杉母树主要生长所在地恩施境内形成立体的硒资源环境,而该区的水杉群落天然更新困难,林下鲜见更新幼苗或幼树。因此,结合硒资源,研究硒元素与水杉种子萌发的相互关系对水杉的天然更新繁育具有重要意义。为了揭示硒元素对水杉种子发芽的影响,该研究通过测定不同环境条件(温度:20、25、30 ℃; 光照:12 h光照/12 h黑暗、24 h全黑暗; 是否浸种)下原生水杉种子的萌发率,筛选出最适萌发条件,并在此条件下采用不同浓度(0、0.25、0.5、1.0、2.0、4.0、8.0、16.0 mg·L^-1)的亚硒酸钠对水杉种子进行处理,观察其萌发的变化。结果表明:当使用浓度为0.25 mg·L^-1的亚硒酸钠溶液处理水杉种子时,种子的发芽率、发芽势和发芽指数都为最高,分别为34.0%、29.0%、13.9; 当亚硒酸钠浓度大于0.25 mg·L^-1时,水杉种子的发芽率、发芽势和发芽指数开始随着浓度的增加而降低,在亚硒酸钠浓度为16.0 mg·L^-1时,三个指标都达到最低值,分别为0.5%、0%、0.025。由此可知,低浓度(0～0.25 mg·L^-1)的亚硒酸钠处理对水杉种子的萌发有一定的促进作用,而高浓度(>0.25 mg·L^-1)的亚硒酸钠处理对水杉种子的萌发则有一定的抑制作用。

Abstract:

Selenium is a trace element needed for plant growth. Enshi in which the stereoscopic natural selenium resources have been formed is the main growing place for the seed trees of Metasequoia glyptostroboides. M. glyptostroboides communities in this area are difficult to regenerate naturally, and seedlings or saplings are rarely seen under the forest. Therefore, studying the relationship between selenium and M. glyptostroboides seed germination under this environment will have great significance to explore the effects of selenium on seed germination of M. glyptostroboides combining selenium resources in Enshi. According to this ecological significance, the germination rate of M. glyptostroboides seeds was determined under different environmental conditions(20, 25, 30 ℃; 12 h Light/12 h dark cycle; pre-soaking or no-soaking), and the optimum germination conditions were selected. Under this selected conditions, different concentrations of sodium selenite(0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0 mg·L^-1)were used to soak the seeds of M. glyptostroboides and their germination changes were observed. The results showed that the highest value of the average germination rate(34.0%), average germination energy(29.0%)and average germination index(13.9)of M. glyptostroboides seeds were appeared at the sodium selenite concentration of 0.25 mg·L^-1. The germination rate, germination energy and germination index of M. glyptostroboides seeds were decreased with the increase of sodium selenite concentration when the concentration higher than 0.25 mg·L^-1, and the values got the lowest at 16.0 mg·L^-1, which were 0.5%, 0% and 0.025, respectively. It can be proved that the low concentration of sodium selenite(0-0.25 mg·L^-1)can promote the germination of M. glyptostroboides seeds, while the treatment with high concentration of sodium selenite(>0.25 mg·L^-1)has some certain inhibitory effects on the germination of M. glyptostroboides seeds. The findings will prove some theoretical support for field nursery and natural regeneration of M. glyptostroboides.