Biomass allocation to vegetative and reproductive organs in Lotus glaber and L. corniculatus (Fabaceae)

Abstract

Comparative studies on reproductive and vegetative attributes between Lotus glaber Mill. and L. corniculatus L. showed that under identical growth conditions seed and pod production were higher in L. glaber than in L. corniculatus. The objective of this work was to determine whether differences in reproductive output between L. glaber and L. corniculatus are related to differences in biomass allocation and whether they can be related to the habitats of each species. We compared, in two studies, the allocation of vegetative and reproductive biomass of both species' growth in pots outdoors. The shoot to root ratio was higher in L. glaber than in L. corniculatus. Both species allocated the same biomass to stems but L. corniculatus produced fewer reproductive stems of higher specific weight. The number of pods per umbel and seeds per pod did not differ between species, but the total number of umbels, pods and seeds per plant were higher in L. glaber than in L. corniculatus. Weight per pod was higher in L. corniculatus than in L. glaber. The reproductive biomass in L. glaber was distributed in a higher number of pods and seeds that were of lower weight than in L. corniculatus. In both species, pod length and seed number per pod showed a decreasing trend during the reproductive season and both attributes were positively correlated. Some of the differences reported in reproductive and vegetative attributes are consistent with the conditions of habitat where each species grows. The results are discussed in relation to the agronomic values of these species and the factors determining their persistence and distribution in the grassland.