ICAR-National Institute for Plant Biotechnology, LBS Centre, Indian Agricultural Research Institute, New Delhi, 110012, India.
Division of Plant Physiology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India.
Plant Sci. 2021 Jul;308:110878. doi: 10.1016/j.plantsci.2021.110878. Epub 2021 Mar 15.
Oryza coarctata is an obligate halophyte of wild species of rice which thrives well under high saline as well as submerged conditions. We report here for the first time that O. coarctata is triploid (2n = 3x = 36), though it was previously known as tetraploid (2n = 4x = 48). The chromosome number of O. coarctata was determined from mitotic plates of root tips and ploidy level was determined by flow cytometer, where it was found to be triploid (2n = 3x = 36). In addition, this species was found to possess several unique anatomical features in leaves such as presence of Kranz-anatomy, increased vein density and higher ratio of bundle sheath to mesophyll cell area as compared to rice variety (IR-29). Ultra-structure of leaf showed the presence of bundle sheath cells with significant number of chloroplasts and mitochondria which were arranged centrifugally. Chloroplasts lack grana in bundle sheath cell whereas, mesophyll cell contain well-developed grana. These anatomical and ultra structural characteristics indicate that this plant is in initial stage of evolving towards C4 photosynthesis due to high selection pressure which might help it to survive in wide range of ecological conditions i.e. from submerged saline to non-saline terrestrial condition.
籼稻(coarctata)是一种野生稻的必需盐生植物，在高盐和淹没条件下生长良好。我们首次报道，籼稻(coarctata)是三倍体(2n = 3x = 36)，尽管它以前被认为是四倍体(2n = 4x = 48)。籼稻(coarctata)的染色体数目是从根尖的有丝分裂板中确定的，而倍性水平是通过流式细胞仪确定的，结果发现它是三倍体(2n = 3x = 36)。此外，与水稻品种(IR-29)相比，该物种的叶片还具有一些独特的解剖特征，如存在 Kranz 解剖结构、叶脉密度增加和束鞘细胞与叶肉细胞面积的比例较高。叶片的超微结构显示，束鞘细胞中存在大量的叶绿体和线粒体，这些细胞器呈离心排列。在束鞘细胞中，叶绿体缺乏基粒，而叶肉细胞中含有发育良好的基粒。这些解剖学和超微结构特征表明，由于高选择压力，该植物正处于向 C4 光合作用进化的初始阶段，这可能有助于它在广泛的生态条件下生存，即从淹没的盐生环境到非盐生陆地环境。
