A light and electron microscope investigation of the transfer cell region of maize caryopses

Abstract

1990. A light and electron microscope investigation of the transfer cell region of maize caryopses. Can. J. Bot. 68: 471-479.The transfer cell zones from 23-day postpollination corn caryopses were examined using light and electron microscopes and X-ray elemental analysis. The transfer cells were sectioned in cross and longitudinal planes and were characterized by having numerous cell-wall extensions in the form of anastomosing lamellae. The most basal transfer cells had more cell-wall extensions than those that were successively deeper in the endosperm. Cytoplasm, rich with mitochondria, filled the interstices of cell-wall extensions, and many vesiculate areas could be found along the plasma membrane. Some transfer cells contained crystals within plastids. The crystals were composed of magnesium, phosphorus, calcium, and zinc. Other cells had large aggregations of endoplasmic reticulum that were often in close association with mitochondria or unidentified, single membrane bounded organelles. When viewed in cross section, the cell-wall extensions of contiguous cells tended to originate from common loci. Plasmodesmata were absent in the bottom parts of the basal transfer cells where they contacted the maternal tissue but were abundant in the upper parts of these cells and in the transfer cells found deeper in the endosperm. The plasmodesmata were found in clusters and alternated with the wall extension areas.

Miniature1-Encoded Cell Wall Invertase Is Essential for Assembly and Function of Wall-in-Growth in the Maize Endosperm Transfer Cell

“…1B). Davis et al (1990) observed a similar gradient in 23-DAP BETCs in a variety of field corn, TX5855.…”

“…The BETL is at the base of the endosperm adjacent to the maternal pedicel tissue, and this is the outermost filial cell layer in direct contact with the maternal pedicel. The BETL is composed of two to three strata of highly specialized transfer cells (Kiesselbach, 1949;Davis et al, 1990). The major morphological feature of the transfer cell is the labyrinth-like proliferation of their cell wall into the cytoplasm, called wall-in-growth (WIG), which serves to increase the plasma membrane area.…”

“…maize (Felker and Shannon, 1980;Davis et al, 1990;Miller and Chourey, 1992;Cheng et al, 1996;Brugiere et al, 2008;Jain et al, 2008). Additionally, many BETLspecific gene markers (i.e.…”

Maize early endosperm growth and development: From fertilization through cell type differentiation

“…Monjardino et al (2007) observed maize endosperm cellularization (also using kernels embedded in plastic resin) and described unorganized alveoli that rapidly formed cells in the central vacuole during late cellularization, which corresponds with our description of partitioning. The large, irregular cells formed during partitioning may help explain how the large and uniquely shaped maize In maize, cells that exhibit transfer cell morphology include the single basal layer directly above the chalazal pad, and the adjacent 3-4 cell layers that contain a gradient of ingrowths decreasing toward the interior of the endosperm ( Kiesselbach and Walker, 1952 ;Schel et al, 1984 ;Davis et al, 1990 ;Gao et al, 1998 ;Thompson et al, 2001 ;Monjardino et al, 2013 ). Most authors identify the single layer of transfer cells directly above the chalazal pad as being morphologically distinct, often referred to as the BETL.…”

The Maize Transcription Factor Myb-Related Protein-1 Is a Key Regulator of the Differentiation of Transfer Cells

“…Aleurone cells expressing MRP-1 acquired the features of endosperm TCs (Royo et al, 2007), forming what has here been called an EETL (Figure 2). The development of an extensive network of CWIs is among the best characterized of TC features (for an ultrastructural characterization of maize TC CWIs, see Davis et al, 1990). These ingrowths provide the increase in plasma membrane surface area needed to enhance the transport function of the TC (reviewed in Pate and Gunning, 1972;Offler et al, 2002) and are clearly observed in the EETL (Figure 2; see diagram in Supplemental Figure 2 online).…”