新疆阿魏雄性不育的细胞形态学研究

Morphological and cytological studies on male sterility in Ferula sinkiangensis

关键词:  濒危植物, 新疆阿魏, 雄性不育, 形态学, 细胞学

Key words:  endangered plant, Ferula sinkiangensis, male sterility, morphology, cytology

摘要:

新疆阿魏是特产于我国新疆的伞形科阿魏属多年生一次结实草本植物,属于国家二级保护的濒危植物。其种群中除了该科植物典型的雄全同株个体以外,还具有一定数量雄性不育的雌株。为了探究新疆阿魏的雄性不育现象及其影响因素,该文从细胞形态学角度对种群中的雌株以及雌花的形态特征进行了观测,采用石蜡切片技术对功能性雌花雄蕊的花药败育过程进行了观察。结果表明:(1)雌株3月底萌动,4月中旬进入花期,5月底果实成熟; 物候期与雄全同株个体相同。(2)植株高度(71.00±10.92)cm和直径(71.67±17.64)cm、一级分支(23.83±2.04); 基生叶长(33.41±11.63)cm、宽(24.47±8.60)cm; 在植株大小、基生叶大小等方面雌株与雄全同株个体无差异。(3)在雌株上,一级分支和二级分支均为雌花序,均可结实; 雌花序的伞幅数/每复伞花序(13.22±4.70)、花数/每花序(12.03±2.30)、总花数/每复伞花序(159.08)均高于两性花序; 雌株比雄全同株个体产生更多可结实的花,形成更多具有杂种优势的异交后代。(4)雌花序中,花排列紧密,花间距小于两性花序和雄花序; 开花时,雌花花瓣微微张开,与两性花、雄花花瓣向下反折的形态明显不同。(5)功能性雌花的花瓣形态、雌蕊形态及大小与两性花/雄花无差异,但是花瓣大小[长(1.79±0.39)mm、宽(1.10±0.21)mm]、雄蕊长度(0.6～1.3)mm最小,花药退化,无花粉。(6)在雌花退化雄蕊的花药发育过程中,出现了花药壁和雄配子体的异常发育; 花药败育发生在造孢细胞时期至小孢子四分体时期。综上所述,新疆阿魏雄性不育植株的营养供给与雄全同株个体相同,但是资源分配模式不同; 功能性雌花在形态和功能上明显区别于两性花和雄花; 其雄蕊败育的主要影响因素是药壁结构的异常发育,尤其是绒毡层的缺失导致了小孢子败育。

Abstract:

Ferula sinkiangensis is a perennial herb, producing fruits only once through its life history, and exclusively habitated in Xinjiang being in the list of state rare and endangered plants Level 2. Besides andromonoecy, usually found in Umbelliferae, plants of male sterility were observed in their populations. Aimed to male sterility and the factors inducing it, comparative observation on morphology of male sterility individuals and functional female flowers were executed through field investigation, and study on cytology of the process of the anther degeneration in female flowers were made from paraffin sections. The results were as follows:(1)Female plants germinated at the end of March and blossomed in the middle of April, and their fruits matured at the end of May; Phenological phases of them were the same as those of andromonoecy.(2)The average height and diameter of plant, and number of the first level branch of female individuals were(71.00±10.92)cm,(71.67±17.64)cm, and(23.83±2.04), separately; The average length and width of basal leaves were(33.41±11.63)cm and(24.47±8.60)cm; The female and the andromonoecy were the same in size of both the plant and the leaf.(3)On female plants, inflorescences on the first and the second level branches were all female, which could bear fruits wholly; The number of umbels in the inflorescence(13.22±4.70)and number of flowers in the umbel(12.03±2.30)and number of total flowers in the inflorescence(159.08)were higher than those in individuals of hermaphrodite; Female plants produced more flowers which could set fruits and bore out-crossing seeds of heterosis.(4)In female umbels flowers located tightly and the distance among flowers were shorter than those in both hermaphrodite and male umbels; Female flowers opened slightly in the whole flowering stage, while petals of both hermaphrodite and male flowers folded reversely.(5)There were no differences in morphological characteristics of petals and pistils among different sexual flowers. But the length(1.79±0.39 mm)and width(1.10±0.21 mm)of petals, and the length of stamens(0.6-1.3 mm)in the functional female flower were the smallest, where anthers degenerated and no pollen stain well developed.(6)Abnormal development of the anther on the degenerated stamen appeared in both of parietal cells and male gametophytes from sporogenous cell stage to microspore tetrad stage. In conclusion, the nutrients productivity in plants of male sterility is similar as andromonoecy, but patterns of resource distribution are quite different; there are significant differences between female and hermaphrodite/male flowers in both the morphology and the function; abnormal development of parietal cells, especially because of the lack of tapetum, caused abortion of microspores in the functional female flower.