Scanning electron microscopy of mature grains of rye, wheat and triticale with emphasis on grain shrivelling

Abstract

Heneen, W. K. and Brismar, K. 1987. Scanning electron microscopy of mature grains of rye, wheat and triticale with emphasis on grain shrivelling. —Hereditas 107:147–162. Lund, Sweden. ISSN 0018–0661. Received December 12,1986 Mature grains from a wheat variety, a rye variety and four triticale lines were studied using scanning electron microscopy. Grain shrivelling was pronounced in two of the tnticale lines. Analysis of entire and transver‐sally cleaved kernels revealed textural features that were common or specific for wheat, rye and/or triticale. Grain shrivelling in triticale was associated with the presence of cavities, primarily in the pericarp, central endosperm, crease and aleurone/subaleurone regions. Microorganisms were often found in the pericarp cavities and sometimes in endosperm cavities as well. The aleurone cells were occasionally shrunken, not completely filled and contained heterogeneous aleurone grains. The endosperm cells, specially those in the vicinity of cavities, often contained empty spaces, less matrix proteins, and the small starch granules were reduced in number or lacked completely. Large starch granules showing typical a‐amylase degrading effects were found, mainly in endosperm cells bordering kernel cavities. Also cell walls in these areas were hard to differentiate. The various features observed in the tnticale lines with shrivelled grains denote the relevance of the following factors in connection with the shrivelling problem: (1) The degrading effects of amylolytic, proteolytic and cell wall breaking enzymes. (2) The decrease in starch synthesis and accumulation of dry matter. (3) The devolopmental imbalance between kernel size determinants and grain filling potential. Further developmental and cytological aspects must be considered in this context.

Effects of salinity stress on starch morphology, composition and thermal properties during grain development in triticale

“…We found that pits are developed from the mid grain-filling stage and proportionally increased with the increase of salinity stress levels. Such a pitting phenomenon was also observed in wheat grains in response to high temperature (Hurkman and Wood 2011) as well as in shriveled cereal grains (Heneen and Brismar 1987). Starch synthesis machinery fosters appropriate interactions with its components to synthesize starch and deposit the glucose polymers in an ordered manner to form granules (Hannah and James 2008).…”

Water stress during grain development affects starch synthesis, composition and physicochemical properties in triticale

“…Another effect of water stress on starch morphology is the pits on the granule surfaces, which begin to appear at the mid grain filling stage and are proportional to the different levels of water stress. Such a pitting phenomenon was also observed in wheat seeds in response to high temperature (Hurkman and Wood, 2011) and triticale starch under germination or enzymatic hydrolysis , as well as in cereal shrivelled grains (Heneen and Brismar, 1987). The disruption or changes in gene expression under water stress may have contributed to such deformities on the granule surface (Szucs et al, 2010).…”

Development of Hexaploid (AABBJJ) Tritipyrums with rearranged Thinopyrum distichum (Thunb.) Á Löve‐derived Genomes

“…The starch granule surfaces are normal and do not show any holes typical of α‐amylase attack. The endosperm cells do not harbor cavities indicative of the degradation of previously laid down matrix proteins as is typically seen in triticale (Heneen and Brismar, 1987).…”