Final grain weight is not limited by the activity of key starch-synthesising enzymes during grain filling in wheat

Since starch is by far the major component of the mature wheat grain, it has been assumed that variation in the capacity for starch synthesis during grain filling can influence final grain weight. We investigated this assumption by studying a total of 54 wheat genotypes including elite varieties and landraces that were grown in two successive years in fields in the east of England. The weight, water content, sugars, starch, and maximum catalytic activities of two enzymes of starch biosynthesis, ADP-glucose pyrophosphorylase and soluble starch synthase, were measured during grain filling. The relationships between these variables and the weights and starch contents of mature grains were analysed. Final grain weight showed few or no significant correlations with enzyme activities, sugar levels, or starch content during grain filling, or with starch content at maturity. We conclude that neither sugar availability nor enzymatic capacity for starch synthesis during grain filling significantly influenced final grain weight in our field conditions. We suggest that final grain weight may be largely determined by developmental processes prior to grain filling. Starch accumulation then fills the grain to a physical limit set by developmental processes. This conclusion is in accord with those from previous studies in which source or sink strength has been artificially manipulated.

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Author Fahy, Brendan
Last Updated August 7, 2019, 10:53 (UTC)
Created July 31, 2019, 16:29 (UTC)
Article Host Type publisher
Article Is Open Access true
Article License Type implied-oa
Article Version Type publishedVersion
Citation Report
DFW Organisation JIC
DFW Work Package 2
DOI 10.1093/jxb/ery314
Date Last Updated 2019-04-06T02:49:31.835804
Evidence open (via page says Open Access)
Journal Is Open Access false
Open Access Status hybrid
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