Distribution between parts of the main shoot and the tillers of photosynthate produced before and after anthesis in the top 3 leaves of main shoots of hobbit and maris huntsman winter wheat triticum aestivum

Thorne, G.N.

Annals of Applied Biology 101(3): 553-560


ISSN/ISBN: 0003-4746
Accession: 005175863

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The top 3 leaves of main shoots in crops of 'Hobbit' and 'Maris Huntsman' winter wheat were exposed to 14CO2 at 22 and 16 days before and at 10 days after anthesis in 1978. The distribution of the 14C recovered in whole plants at anthesis and at maturity was measured. There was negligible loss of 14C between these 2 times, but some redistribution. The percentage in the tillers was negligible when the flage leaf (leaf 1) was exposed to 14CO2, and otherwise less than 12% except for 14C absorbed by the 3rd leaf at 16 days before anthesis, when it averaged 26% but was very variable. When 14C was supplied before anthesis, about 20% reached the grain whichever leaf had been supplied. The ear structures contained about 10% of that absorbed by the 3rd leaf and 35% of that absorbed by the flag or 2nd leaf. When 14C was supplied after anthesis, the amounts reaching the grain from the different leaves were: flag 82%, 2nd 68%, 3rd 56%. Most of the remainder was in the stem. The exposed leaf never retained more than 6%. The amount of 14C that moved from the stem to the grain between anthesis and maturity was about 50% greater in the semi-dwarf variety Hobbit than in Maris Huntsman. There was no significant varietal difference in the percentage of post-anthesis 14C reaching the grain. The ear structures of Hobbit contained about a third more 14C than those of Maris Huntsman. An additional 90 kg N ha-1, which increased grain yield by 46%, had negligible effects on the distribution of 14C.