半蒴苣苔属植物染色体制片优化及染色体数目和倍性研究

染色体数目和倍性是系统与进化生物学和遗传学研究中十分重要的基础信息。为探索半蒴苣苔属染色体制片的适宜条件以及染色体数目的进化模式及其与物种的进化关系,该研究基于半蒴苣苔属染色体数目的进化历史,并根据该属植物具有叶片扦插繁殖的特性,采用叶片水培生根法获取半蒴苣苔(Hemiboea subcapitata)、弄岗半蒴苣苔(H.longgangensis)、龙州半蒴苣苔(H.longzhouensis)、江西半蒴苣苔(H.subacaulis var.jiangxiensis)、华南半蒴苣苔(H.follicularis)和永福半蒴苣苔(H.yongfuensis)6种植物的根尖材料,分析不同实验条件对染色体制片效果的影响,对染色体制片实验的条件进行优化及染色体计数,结果表明:(1)9:30—10:00取材,解离10 min以及染色15 min为半蒴苣苔属染色体制片的适宜条件。(2)上述6种半蒴苣苔属植物均为二倍体,染色体数目均为32(2n=2x=32)。(3)除个别物种染色体数目有变化以外,该属大部分物种染色体数目可能为2n=2x=32且染色体数目变化可能是非整倍化的作用,与物种进化没有明显关系。该研究结果为半蒴苣苔属以及具有类似叶片再生植株特性类群的染色体制片提供了参考,并为该类群的分类、系统进化等方面的研究提供了启示。

药用红树植物小花老鼠簕繁育研究

为实现小花老鼠簕种群恢复和药用资源开发,对小花老鼠簕繁育方法进行了研究。以小花老鼠簕成熟无病虫害叶片为水培材料,以霍格兰营养液为水培基质,以IAA和NAA的浓度梯度及浸泡时间为试验因素,设计三因素四水平正交试验,经比较诱导生根率、根系形态建成及根系活力探究最优水培条件。比较叶片水培苗和种子土培苗药用成分(生物碱)差异,评价叶片水培效果。结果表明,小花老鼠簕叶片水培易生根。水培液最优激素浓度和处理时间为:1 mg/L IAA+1.5 mg/L NAA+24 h,生根率达80%,成活率为73.3%。小花老鼠簕水培苗和土培苗生物碱成分无明显差异。通过水培进行小花老鼠簕药用资源的综合利用是经济有效的方式。

A Comparative Study on the Leaf Characteristics and Root Vigor of Bowl Lotus under Hydroponics and Soil Culture

[Objective] The experiment aimed to study the growth characteristics of hydroponic bowl lotus. [Method] The lotus variety Hongxia was chosen as the experimental material. Two treatments, hydroponics and soil culture were set to measure their photosynthetic indices, chlorophyll content and root vigor, and to observe their leaf tissue structure and stomatal characteristics. [Result] The findings indicated that there are no differences in the leaf physiological indices between bowl lotus under hydroponics and soil culture, while the leaf stomata of hydroponic bowl lotus is bigger and its amount is larger than that of soil-culture bowl lotus. At the same time, the ratio of the palisade tissue thickness to spongy tissue thickness is small,and its leaf tissue structure is loose. The root vigor of hydroponic bowl lotus reached its summit earlier, then began to drop. Whereas, the root activity of soil-culture lotus sustained increasing, with vigorous growth. [Conclusion] Therefore, it indicated that hydroponic bowl lotus can adapt to the aquatic-culture environment well and quickly, meanwhile, it also enters into its aging period quickly and its growth cycle gets shorter.

Cultivating Rice with Delaying Leaf-Senescence by P_(SAG12)-IPT Gene Transformation

P SAG12 _ IPT gene was introduced into an elite rice (Oryza sativa L. ssp. indica ) restorer line Minghui 63 through Agrobacterium _mediated transformation method. Out of 61 independent transgenic plants obtained, a few acquired a recognizable phenotype in which leave senescence was delayed to a great degree. The results of field plot test on two homozygous transgenic lines indicated: (1) the stay_green ability of transgenic plants was significantly improved; (2) both the seed_setting rate and the number of panicles per plant of transgenic plants were significantly increased compared with that of the non_transgenic plants of Minghui 63; and (3) the plant height of transgenic plants was significantly reduced.