scholarly journals Structure and histochemistry of sorghum caryopsis in relation to grain-filling

2020 ◽  
Vol 12 (4) ◽  
pp. 852-868
Author(s):  
S. RAVI SHANKAR ◽  
P. DAYANANDAN

Anatomical and histochemical studies of ovary and caryopsis of sorghum reveal the importance of the chalazal complex in transporting nutrients from maternal sources to the filial diploid embryo and triploid endosperm. The presence of starch, protein, lipid, Ca, K, Mg, and Fe in various tissues at different stages of development can be revealed by a variety of histochemical techniques. Vascular supply ends at the base of the ovary and transport occurs through vascular parenchyma, pigment strand and nucellar projection where symplastic continuity is broken. Nutrients unloaded into an apoplastic placental sac then enter the endosperm and embryo through the aleurone transfer cells. The later possess characteristic wall ingrowth. The single layer of aleurone surrounding the endosperm may also help in transport during later stages of grain-filling. Grain-filling in C4 sorghum is compared with other C4 and C3 grasses showing the variety of strategies evolved to transport nutrients into filial tissues. Standardization of terminologies to describe the tissues of the crease region will help in further research and communication.

2000 ◽  
Vol 27 (11) ◽  
pp. 1009 ◽  
Author(s):  
Neil Bagnall ◽  
Xin-Ding Wang ◽  
Graham N. Scofield ◽  
Robert T. Furbank ◽  
Christina E. Offler ◽  
...  

In developing wheat grains (Triticum turgidum var. durum cv. Fransawi), post-sieve element transport of phloem-imported photoassimilates (sucrose) includes membrane transport, to and from the grain apoplasm, between symplasmically-isolated maternal and filial tissues. The cellular location and mechanism of these membrane transport steps were explored during rapid grain fill. Genomic Southern analysis indicated the presence of a multigene family of sucrose/H + symporters (SUTs). One or more SUTs were highly expressed in developing grains, as were P-type H + /ATPase(s) and a sucrose binding protein (SBP). Transcripts of these genes were detected in vascular parenchyma, nucellar projection and aleurone cells. Antibodies, raised against a SUT, an H + /ATPase and a SBP, were selectively bound to plasma membranes of vascular parenchyma cells, nucellar projection transfer cells and modified aleurone/sub-aleurone transfer cells. The nucellar projection transfer cells and modified aleurone/sub-aleurone transfer cells exhibited strong proton pumping activity. In contrast, SUT transport function was restricted to filial tissues containing modified aleurone/sub-aleurone transfer cells. Based on these findings, we conclude that SUTs expressed in maternal tissues do not function as sucrose/H + symporters. Membrane exchange from nucellar projection transfer cells to the endosperm cavity occurs by an as yet unresolved mechanism. Sucrose uptake from the endosperm cavity into filial tissues is mediated by a SUT localised to plasma membranes of the modified aleurone/sub-aleurone transfer cells.


2020 ◽  
Vol 71 (16) ◽  
pp. 4617-4620 ◽  
Author(s):  
Tyler J McCubbin ◽  
David M Braun

This article comments on: Wei X, Nguyen ST, Collings DA, McCurdy DW. 2020. Sucrose regulates wall ingrowth deposition in phloem parenchyma transfer cells in Arabidopsis via affecting phloem loading activity. Journal of Experimental Botany 71, 4690–4702.


2010 ◽  
Vol 63 (4) ◽  
pp. 651-661 ◽  
Author(s):  
Joshua Edwards ◽  
Antony P. Martin ◽  
Felicity Andriunas ◽  
Christina E. Offler ◽  
John W. Patrick ◽  
...  

PROTOPLASMA ◽  
2001 ◽  
Vol 215 (1-4) ◽  
pp. 191-203 ◽  
Author(s):  
Mark J. Talbot ◽  
Vincent R. Franceschi ◽  
David W. McCurdy ◽  
Christina E. Offler

PROTOPLASMA ◽  
1994 ◽  
Vol 182 (1-2) ◽  
pp. 39-52 ◽  
Author(s):  
H. L. Wang ◽  
C. E. Offler ◽  
J. W. Patrick

PROTOPLASMA ◽  
2010 ◽  
Vol 242 (1-4) ◽  
pp. 69-80 ◽  
Author(s):  
Néziha Boughanmi ◽  
Florence Thibault ◽  
Raphael Decou ◽  
Pierrette Fleurat-Lessard ◽  
Emile Béré ◽  
...  

2021 ◽  
Vol 12 ◽  
Author(s):  
Yihao Wei ◽  
Shuping Xiong ◽  
Zhiyong Zhang ◽  
Xiaodan Meng ◽  
Lulu Wang ◽  
...  

Glutamine synthetase (GS) plays a major role in plant nitrogen metabolism, but the roles of individual GS isoforms in grains are unknown. Here, the localization and expression of individual TaGS isozymes in wheat grain were probed with TaGS isoenzyme-specific antibodies, and the nitrogen metabolism of grain during the grain filling stage were investigated. Immunofluorescence revealed that TaGS1;1, TaGS1;3, and TaGS2 were expressed in different regions of the embryo. In grain transporting tissues, TaGS1;2 was localized in vascular bundle; TaGS1;2 and TaGS1;1 were in chalaza and placentochalaza; TaGS1;1 and TaGS1;3 were in endosperm transfer cells; and TaGS1;3 and TaGS2 were in aleurone layer. GS exhibited maximum activity and expression at 8 days after flowering (DAF) with peak glutamine content in grains; from then, NH4+ increased largely from NO3- reduction, glutamate dehydrogenase (GDH) aminating activity increased continuously, and the activities of GS and glutamate synthase (GOGAT) decreased, while only TaGS1;3 kept a stable expression in different TaGS isozymes. Hence, GS-GOGAT cycle and GDH play different roles in NH4+ assimilation of grain in different stages of grain development; TaGS1;3, located in aleurone layer and endosperm transfer cells, plays a key role in Gln into endosperm for gluten synthesis. At 30 DAF, grain amino acids are mainly transported from maternal phloem.


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