2021年10月22日 星期五
假俭草花序发育的形态学观察及其与物候期和积温的对应关系
Morphological observation on inflorescence development of Eremochloa ophiuroides and its corresponding relationships with phenophase and accumulated temperature
2021年 第30卷 第5期 页码[50-57]    下载全文[7.2MB]  
摘要

采用连续取样法对假俭草品种‘渝西’(Eremochloa ophiuroides ‘Yuxi’)花序发育的形态特征变化进行了观察,并对花序发育各时期对应的物候期和≥5 ℃积温进行了分析。结果显示:假俭草的花序发育是一个连续变化的过程,可依次划分为8个时期:生长锥初生期、生长锥伸长期、苞叶原基分化期、小穗原基分化期、小穗分化期、小花分化期、雌雄蕊形成期和开花期;其中,生长锥初生期对应返青期,生长锥伸长期对应孕穗初期,苞叶原基分化期至小花分化期4个时期对应孕穗期,雌雄蕊形成期对应抽穗期,开花期对应始花期。生长锥初生期的生长锥呈半球状突起,进入生殖生长后,生长锥伸长发育成半透明的圆柱状穗轴原基,表面连续形成并排排列的苞叶原基,随后在苞叶原基基部产生半透明球状小穗原基,进而在小穗原基基部形成碗状颖片原基;穗轴外侧的2列小穗为有柄小穗并最终退化,而中间2列小穗为无柄小穗,每个小穗发育出1个雄性花原基和1个两性花原基;而后雄蕊原基由半球状逐渐发育成四棱柱状花药,雌蕊原基由小突起逐渐发育成柱头、花柱和子房,最后花药和柱头伸出颖外,小花开放。花序中上部小穗分化最早,后依次向上、向下进行,花序基部小穗分化最晚,每个小穗分化出1朵雄性花和1朵两性花,其开花顺序是自中上部小穗上的小花向花序两端开放。生长锥初生期、生长锥伸长期、苞叶原基分化期、小穗原基分化期、小穗分化期、小花分化期、雌雄蕊形成期和开花期的假俭草生长锥平均长度分别为201、415、1 065、2 169、3 024、8 534、28 148和155 097 μm,单个生殖枝的平均叶片数分别为4.2、4.4、4.3、4.5、4.4、4.5、4.5和4.5枚。生长锥初生期持续时间约55 d,其他时期持续时间约4或5 d,对应的≥5 ℃积温为1 217.5 ℃~1 888.5 ℃; 当≥5 ℃积温达到1 217.5 ℃时,假俭草进入生长锥伸长期,该时期是假俭草从营养生长转向生殖生长的转折点。根据观察结果,建议将≥5 ℃积温作为判断假俭草花序发育的指标之一。

Abstract

 The variations of morphological characteristics of inflorescence development of Eremochloa ophiuroides ‘Yuxi’ were observed by using a continuous sampling method, and the phenophase and accumulated temperature of ≥5 ℃ corresponding to each stage of inflorescence development were analyzed. The results show that the inflorescence development of E. ophiuroides is a process of continuous variation, which is successively divided into eight stages: cone primary stage, cone extension stage, bract primordium differentiation stage, spikelet primordium differentiation stage, spikelet differentiation stage, floret differentiation stage, pistil and stamen formation stage and flowering stage; in which, the cone primary stage corresponds to the re-greening stage, the cone extension stage corresponds to the initial booting stage, the four stages from bract primordium differentiation stage to floret differentiation stage correspond to the booting stage, the pistil and stamen formation stage corresponds to the heading stage, and the flowering stage corresponds to the initial flowering stage. The cone has hemispherical protuberance at the cone primary stage, after entering reproductive growth, the cone elongates and develops into a translucent cylindrical spike stalk primordium, and the surface continuously forms bract primordium arranged side by side, and then translucent globular spikelet primordium is produced at the base of bract primordium, and bowlshaped glume primordium is formed at the base of spikelet primordium; the two lines of spikelets on the outer side of the spike stalk are petiolate spikelets and finally degenerated, while the two lines of spikelets in the middle are sessile spikelets, and each spikelet develops a male flower primordium and a bisexual flower primordium; after that the stamen primordium gradually develops from hemispherical to quadrilateral anther, the pistil primordium gradually develops from small protuberance into stigma, style. and ovary, and finally the anther and stigma extend out of the glume, and the floret opens. The middle and upper spikelets of the inflorescence differentiate the earliest, and then proceed upward and downward in turn, the spikelets at the base of the inflorescence differentiate the latest, and each spikelet differentiates into a male flower and a bisexual flower, and its flowering order is from the florets in the middle and upper spikelets to both ends of the inflorescence. The average length of cone of E. ophiuroides in cone primary stage, cone extension stage, bract primordium differentiation stage, spikelet primordium differentiation stage, spikelet differentiation stage, floret differentiation stage, pistil and stamen formation stage and flowering stage is 201, 415, 1 065, 2 169, 3 024, 8 534, 28 148 and 155 097 μm, respectively, and the average number of leaf per reproductive branch is 4.2, 4.4, 4.3, 4.5, 4.4, 4.5, 4.5 and 4.5, respectively. The duration of the cone primary stage is about 55 d, while that of other stages is about 4 or 5 days, and the corresponding accumulated temperature of ≥5 ℃ is 1 217.5 ℃-1 888.5 ℃; when the accumulated temperature of ≥5 ℃ reaches 1 217.5 ℃, E. ophiuroides will turn into the cone extension stage, and this stage is the turning point of E. ophiuroides from vegetative growth to reproductive growth. According to the observation results, it is suggested that the accumulated temperature of ≥5 ℃ can be used as one of indexes to judge the inflorescence development of E. ophiuroides.

关键词假俭草; 花序发育; 形态特征; 物候期; ≥5 ℃积温
Key wordsEremochloa ophiuroides (Munro) Hack.; inflorescence development; morphological characteristics; phenophase; accumulated temperature of ≥5 ℃
作者宗俊勤, 牛佳伟, 徐芳, 陈静波, 郭爱桂, 郭海林, 刘建秀
所在单位江苏省中国科学院植物研究所(南京中山植物园) 国家林业和草原局暖季型草坪草种质创新与利用工程技术研究中心, 江苏 南京 210014
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基金项目科技基础资源调查专项(SQ2016FY326000402); 省属公益类科研院所自主科研项目(JSPKLB202049); 江苏省水利科技项目(2019061)