伞形科植物芫荽果实发育过程中的解剖结构变化

Change of fruit anatomical structure of Coriandrum sativum(Apiaceae) during fruit development process

采用常规石蜡切片法对伞形科(Apiaceae)芹亚科(Apioideae Drude)芫荽属(Coriandrum Linn.)种类芫荽(Coriandrum sativum Linn.)花后幼果发育阶段和果熟发育阶段的果实横切面解剖结构及其变化进行了观察和比较。观察结果表明:芫荽果实的幼果和果熟发育阶段均分为前期、中期和后期3个时期,不同时期果实横切面的形状和大小、果壁厚度和结构以及合生面、果棱、维管束、油管、胚乳和结晶等特征均有明显变化。在芫荽果实发育过程中,果实横切面由近椭圆形逐渐变为近圆形,且分生果长度从1 630μm增加至3 290μm、宽度从860μm增加至1 580μm。合生面长度与分生果长度相等,但合生面逐渐分离,成熟的2个分生果仅由心皮柄维管束和合生面两端的外果壁及中果壁最外侧数层细胞相连,从外形看2个分生果不分离。果壁由薄变厚、再由厚变薄,明显分为4个层次;成熟果实的中果壁大部分由木化细胞构成。果棱可分为主棱和次棱2种,且均不发达;次棱呈角状突起、主棱呈波状弯曲,次棱较主棱明显。维管束包括果壁维管束、心皮柄维管束和种脊维管束3类,其中,果壁维管束不发达且散布于中果壁木化细胞层中。油管仅存在于合生面并被逐渐压扁,而果壁油管消失并转变成大空腔。胚乳逐渐膨大,其形状由元宝形逐渐转变为船形或肾形。此外,在幼果发育阶段,中果壁薄壁细胞、合生面和胚乳细胞中或多或少都含有结晶,胚乳细胞中还含有大量糊粉粒结晶;但在果熟发育阶段结晶消失,仅胚乳细胞中存有糊粉粒结晶。分析结果显示:芫荽果实属隐性双悬果类型且果棱属微果棱型,其部分解剖结构与伞形科芹亚科多数种类的果实有差异。

The anatomical structures and their changes in fruit transection of Coriandrum sativum Linn. in Coriandrum Linn. belonging to Apioideae Drude of Apiaceae during development periods of young and mature fruits after flower falling were observed and compared by normal paraffin section method. The observation results show that development periods of young and mature fruits can be divided into three stages of early, middle and late, and at different stages, there are obvious changes in shape and size of fruit transection, thickness and structure of carpodermis, and characteristics of commissure, rib, vascular bundle, vittae, endosperm and crystal. During fruit development process, shape of fruit transection changes from sub-ellipse to subround, and mericarp length enlarges from 1 630μm to 3 290μm and its width from 860μm to 1 580μm. Length of commissure is equal to that of mericarp, but the commissure separates gradually and two matural mericarps are combined only by mean of vascular bundle of earpophore and epicarp and some cell layers out of mesocarp at the ends of commissure, so two mericarps seem not separated on external from thick to thin, it can be morphology. Thickness of carpodermis changes from thin to thick and then obviously divided into four layers; most of mesocarp in mature fruit are composed with lignified cells. Fruit ribs can be divided into two types of main rib and secondary rib and both are not developed; secondary rib appears coruiculate and main rib seems wavy bending, the former （secondary rib） is more obvious than the latter. Vascular bundles include three types of earpodermis, carpophore and raphe, in which, vascular bundles of earpodermis are not developed and scatter in lignified cell layer of mesocarp. Vittaes only exist in commissure and are squashed gradually, while vittaes of carpodermis vanish and change into big cavities. Endosperm enlarges gradually and its shape changes gradually from sellaeform to ship-form or reniform. Moreover, there are more or less crystals in mesocarp parenchyma cells, in commissure and endosperm cells during development period of young fruit, and there are a lot of aleurone grain crystals in endosperm cells, but during development period of mature fruit, crystals disappear while there are aleurone grain crystals only in endosperm cells. It is indicated that fruit of C. sativum belongs to recessive cremocarp type and its rib belongs to micro-rib type, and its some anatomical structures differ from those of most species in Apioideae of Apiaceae.