SEEDLESS PLANTS Prof. Ms. Vrushali S. Dighe Department Of Botany S. M. Joshi College, Hadapsar, Pune.

Continuing Trends in Plant Evolution Reduction of water-dependent gametophyte Vascular tissue – improved water/food transport More efficient roots, stems, leaves Tissues Stomates Green: all these are in sporophyte

Reduction of gametophyte Specialization in sporophyte

Vascular tissue In sporophyte Interconnects all plant organs Xylem - water Phloem - sugar

Complex leaves Tissues Stomates http://www.fairchildgarden.org/EduProfDev/Images/leaf_cross_section_labled.jpg http://remf.dartmouth.edu/images/ArabidopsisSEM/source/arabidopsis_m1_stomate_1.html

Plant classification review Bryophytes – no seeds, no roots, no vascular Mosses, liverworts, hornworts Seedless, vascular plants – no seeds Ferns, horsetails, club mosses, whisk ferns Gymnosperms - seeds & cones Conifers, cycads, ginkgo, gnetophytes Flowering plants – seeds, flowers & fruits Primitive, Monocots, Dicots

Seedless Vascular Plants Ferns, horsetails, club mosses, whisk ferns Sporophyte dominant Gametophyte small but still tied to water Dominant plants from late Devonian through early Permian Equatorial coal forests Today somewhat marginal, but successful Heterospory in some (next time)

Fern Life Cycle Meiosis Gametophyte Fertilization Sporophyte You do not need to know the details of this life cycle. Just, Where is the gametophyte and sporophyte? Sporophyte

Fern gametophytes … Mature fern sporophyte … … with young sporophytes … with clusters of sporangia

Whisk Fern, Psilotum Psilotum is subtropical Exhibits several very primitive characters No leaves (outgrowths of stem are not vascularized) Dichotomous (equal “Y” shaped) branching of parts Simple sporangia (in 3s) “Roots” and stems similar morphology and vascular tissue simple

Club moss, Lycopodium

Horsetail, Equisetum

Carboniferous (-300 my) coal forest model Lycophyta – Club mosses Sphenophyta – Horse tails Not seen: Tree ferns (Pterophyta) and seed ferns Many giant, tree-sized versions of modern genera Carboniferous (-300 my) coal forest model