Interrelations Between Seeds and Associated Fruiting Structures During Their Development in Trifolium subterraneum L.

Developing burrs of T. subterraneum (cv. Daliak) were subjectedto dark and light treatments in experiments conducted in a controlledtemperature glasshouse with day/night air temperatures of 18/13°C. Post fertilization development of burr components wasfollowed and the effect of removal of seeds or sterile calyoeson the development of the remaining burr components studied. Peduncle elongation took place mainly between days 0 (anthesis)and 7, when the burr would normally have buried. Seed developmentwas completed by day 42. Pod walls attained near maximum weightat about day 22. The perianth increasd in weight between days12 and 22 due to enlargement of the calyx. Sterile calyces wereprduced continuously until day 42. The pattern of burr develompentwas similar in both dark and light, but the weight of the maincomponents were considerably reduced in the light treatment. Normal peduncle development depended on the presence of at leastone seed in the inflorescence. Pod walls did not develop, neitherdid the perianth enlarge unless these structures were associatedwith a developing seed. In the absence of seeds fewer sterilecalyces were produced in the dark treatment and fewer stillwere produced in the light, indicating a direct inhibitory effectof light on the production of sterile calyces. Within matureburrs the weight of pod walls and sterile calyces was closelyrelated to the weight of seeds. Removal of sterile calyces reducedseed production but interpretation of this effect is not clear. Trifolium subterraneum L., fruit development, seed production