title: Development of basal endosperm transfer cells in Sorghum bicolor (L.) Moench and its relationship with caryopsis growth.
abstract: During sorghum caryopsis development, endosperm epidermal cells near the basal main vascular bundle are specialized by depositing wall ingrowths, differentiating into basal endosperm transfer cells (BETCs). All the BETCs together compose the basal endosperm transfer layer (BETL). BETCs are the first cell type to become histologically differentiated during endosperm development. The initiation and subsequent development of BETCs shows the pattern of temporal and spatial gradient. The developmental process of BETL can be divided into four stages: initiation, differentiation, functional, and apoptosis stage. A placental sac full of nutrient solutions would emerge, enlarge, and eventually disappear between the outmost layer of BETL and nucellar cells during caryopsis development. BETCs have dense cytoplasm rich in mitochondria, lamellar rough endoplasmic reticulum, Golgi bodies, and their secretory vesicles. They show a series of typical characteristics of senescence such as nuclei distortion and subcellular organelle deterioration during their specialization. BETCs probably play an active role in nutrient transfer into the starchy endosperm and embryo. The occurrence, development, and apoptosis of BETCs are in close relation to the caryopsis growth and maturation especially the enrichment of endosperm and the growth of embryo. The timing when BETL is fully developed, composed of three to four layers in radial direction and 70 to 80 rows in tangential direction, consists with the timing when average daily gain of caryopsis dry weight reaches its maximum. It is conceivable that measures that delay the senescence and death of BETCs would help to increase the crop yield.
authors.affiliation: Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Crop Physiology, Ecology and Cultivation in Middle and Lower Reaches of Yangtse River of Ministry of Agriculture, Yangzhou University, Yangzhou, Jiangsu, 225009, China.
authors.forename: Hui-Hui
authors.initials: HH
authors.lastname: Wang
authors.forename: Zhong
authors.initials: Z
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Yun-Jie
authors.initials: YJ
authors.lastname: Gu
authors.forename: Zhi
authors.initials: Z
authors.lastname: Liu
mesh_terms: D017209:Apoptosis / Q000502:physiology; D056625:Endosperm / Q000166:cytology* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D010940:Plant Proteins / Q000378:metabolism; D045868:Sorghum / Q000166:cytology* / Q000254:growth & development* / Q000648:ultrastructure
chemical_list: D010940:Plant Proteins