成熟时含油量不同的向日葵品种的瘦果结构、发育及脂质积累
Achene structure, development and lipid accumulation in sunflower cultivars differing in oil content at maturity.
作者信息
Mantese Anita I, Medan Diego, Hall Antonio J
机构信息
Departamento de Recursos Naturales y Ambiente, Universidad de Buenos Aires, Av. San Martin 4453, 1417, Buenos Aires, Argentina.
出版信息
Ann Bot. 2006 Jun;97(6):999-1010. doi: 10.1093/aob/mcl046. Epub 2006 May 4.
BACKGROUND AND AIMS
Sunflower cultivars exhibit a wide range of oil content in the mature achene, but the relationship between this and the dynamics of oil deposition in the achene during grain filling is not known. Information on the progress, during the whole achene growth period, of the formation of oil bodies in the components of the achene and its relationship with variations in final oil content is also lacking.
METHODS
The biomass dynamics of achene components (pericarp, embryo, oil) in three cultivars of very different final oil concentration (30-56 % oil) were studied. In parallel, anatomical sections were used to follow the formation of oil and protein bodies in the embryo, and to observe pericarp anatomy.
KEY RESULTS
In all cultivars, oil bodies were first observed in the embryo 6-7 daa after anthesis (daa). The per-cell number of oil bodies increased rapidly from 10-12 daa until 25-30 daa. Oil bodies were absent from the outer cell layers of young fruit and from mature pericarps. In mature embryos, the proportion of cell cross-sectional area occupied by protein bodies increased with decreasing embryo oil concentration. The sclerenchymatic layer of the mature pericarp decreased in thickness and number of cell layers from the low-oil cultivar to the high-oil cultivar. Different patterns of oil accumulation in the embryo across cultivars were also found, leading to variations in ripe embryo oil concentration. In the high-oil cultivar, the end of oil deposition coincided with cessation of embryo growth, while in the other two cultivars oil ceased to accumulate before the embryo achieved maximum weight.
CONCLUSIONS
Cultivar differences in mature achene oil concentration reflect variations in pericarp proportion and thickness and mature embryo oil concentration. Cultivar differences in protein body proportion and embryo and oil mass dynamics during achene growth underlie variations in embryo oil concentration.
背景与目的
向日葵品种成熟瘦果的含油量差异很大，但这与灌浆期瘦果中油脂沉积动态之间的关系尚不清楚。关于整个瘦果生长期间瘦果各组成部分油体形成过程及其与最终含油量变化关系的信息也很缺乏。
方法
研究了三个最终含油浓度差异很大（含油率30%-56%）的品种瘦果各组成部分（果皮、胚、油脂）的生物量动态。同时，通过解剖切片观察胚中油体和蛋白体的形成，并观察果皮解剖结构。
主要结果
在所有品种中，花后6-7天（daa）在胚中首次观察到油体。每个细胞中的油体数量从花后10-12天到25-30天迅速增加。幼果外层细胞层和成熟果皮中没有油体。在成熟胚中，蛋白体所占细胞横截面积比例随着胚含油浓度的降低而增加。成熟果皮的厚壁组织层厚度和细胞层数从低油品种到高油品种逐渐减少。不同品种胚中油脂积累模式也不同，导致成熟胚含油浓度存在差异。在高油品种中，油脂沉积结束与胚生长停止同时发生，而在其他两个品种中，油脂在胚达到最大重量之前就停止积累。
结论
成熟瘦果含油浓度的品种差异反映了果皮比例、厚度以及成熟胚含油浓度的变化。瘦果生长期间品种在蛋白体比例、胚和油脂质量动态方面的差异是胚含油浓度变化的基础。
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