title: Pisum sativum wild-type and mutant stipules and those induced by an auxin transport inhibitor demonstrate the entire diversity of laminated stipules observed in angiosperms.
abstract: About a quarter of angiosperm species are stipulate. They produce stipule pairs at stem nodes in association with leaves. Stipule morphology is treated as a species-specific characteristic. Many species bear stipules as laminated organs in a variety of configurations, including laterally free large foliaceous, small, or wholly leaf-like stipules, and as fused intrapetiolar, opposite, ochreate or interpetiolar stipules. In Pisum sativum, the wild-type and stipule-reduced and cochleata mutants are known to form free large, small, and leaf-like stipules, respectively. Auxin controls initiation and development of plant organs and perturbations in its availability and distribution in the meristems, caused by auxin transport inhibitor(s) (ATIs), lead to aberrations in leaf development. The effect(s) of ATI(s) on stipule development are unexplored. To study the effect of the ATI 1-N-naphthylphthalamic acid (NPA) on stipule morphogenesis, P. sativum explants were grown in vitro in presence of a sublethal concentration of NPA. The NPA-treated shoots produced fused stipules of all the different types described in angiosperms. The observations indicate that (a) the gene sets for stipule differentiation may be common in angiosperms and (b) the interspecies stipule architectural differences are due to mutations, affecting gene expression or activity that got selected in the course of evolution.
authors.affiliation: Genetical Genomics Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, Post Box 10531, New Delhi 110067, India.
authors.forename: Arvind
authors.initials: A
authors.lastname: Kumar
authors.forename: Vishakha
authors.initials: V
authors.lastname: Sharma
authors.forename: Moinuddin
authors.initials: M
authors.lastname: Khan
authors.forename: Bhumi Nath
authors.initials: BN
authors.lastname: Tripathi
authors.forename: Sushil
authors.initials: S
authors.lastname: Kumar
mesh_terms: D001692:Biological Transport; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005838:Genotype; D007210:Indoleacetic Acids / Q000037:antagonists & inhibitors* / Q000378:metabolism; D018532:Pisum sativum / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D010797:Phthalimides / Q000494:pharmacology*; D010937:Plant Growth Regulators / Q000494:pharmacology
chemical_list: D007210:Indoleacetic Acids; D010797:Phthalimides; D010937:Plant Growth Regulators; C002687:alpha-naphthylphthalamic acid