Assimilate Partitioning in Three White Clover Cultivars in the Autumn, and the Effect of Defoliation

Partitioning of recently assimilated 14 C in three cloned white clover cultivars (Aberherald, Grasslands Huia and Sandra), grown outdoors, was determined at the end of Aug., the end of Sep. and the end of Oct. to examine the relative strength of different sinks within the plant when growing conditions increasingly favour carbohydrate accumulation in relation to growth. Also, the effect of removing two out of three expanded leaves on 14 C partitioning was studied. Export of 14 C from leaves increased from late Aug. to late Oct. More 14 C was partitioned to the roots and less to the apex at the Sep. and Oct. harvests than at the harvest in Aug., irrespective of cultivar. Severe defoliation resulted in more 14 C being partitioned to the apex and less to the main stolon irrespective of cultivar and harvest occasion. Sandra (a cultivar of northern origin) generally partitioned more 14 C to the stolon and less to the apex than did the other two cultivars.