Parallelismic homoplasy of leaf and stipule phenotypes among genetic variants of Pisum sativum and Medicago truncatula and some taxa of papilionoideae, caesalpinioideae and mimosoideae subfamilies of the leguminosae flora of Delhi

Abstract

The leguminous flora of Delhi comprises 78 Papilionoideae, 24 Caesalpinioideae and 24 Mimosoideae species; 80 of them are perennials. Five types of imparipinnate and two types of paripinnate compound leaves were observed in the species. The paripinnate leaves are bipinnate in 25 species (mostly mimosoid) and bifoliate in two species. The imparipinnate leaves were trifoliate or multifoliate in 59 papilionoid species and multifoliate in 16 caesalpinioid species; four of the papilionoid species produced leafletted and tendrilled unipinnate leaves. Leaves were bifacially simple in 22 species, simple with ectopic terminal growth in one species and simple tendril in one species. Twenty-one species (mostly mimosoid) were devoid of stipules. In 82 species stipules were small and free. Stipules were large and lobed in 17 species and large and adnate in four species. Two species of Caesalpinioideae produce compound leaf-like stipules. All four stipule phenotypes of 126 species corresponded with stipular phenotypes observed in wild type, coch, st and coch st genotypes of the model legume P. sativum. The seven leaf phenotypes observed in 126 species corresponded with phenotypes expected among combinations of uni (uni-tac), af, ins, mfp and tl mutants of P. sativum and sgl1, cfl1, slm1 and palm1 mutants of M. truncatula, also an IRL model legume. All the variation in leaf and stipule morphologies observed in the leguminous flora of Delhi could be explained in terms of the gene regulatory networks already revealed in P. sativum and M. truncatula. It is hypothesized that the ancestral gene regulatory networks for leaves and stipules produced in Leguminosae were like that prevalent in P. sativum.