Developmental Morphology of Panicle in Erianthus

Bioethanol is a promising alternative to fossil fuels and a potential countermeasure to global warming. Erianthus, a perennial C4 grass, may be a useful raw material for cellulosic bioethanol, mainly because of its high biomass production potential. Little is known about the developmental morphology of the panicle in Erianthus. In this study the fundamental structure and development of panicle in Erianthus were examined. The inflorescence (panicle) of Erianthus is a raceme with conical appearance. The rachis of the panicle has the first, second and third order rachis branches. The spikelets are formed on every order rachis branch. A pedicellate spikelet and a sessile spiketet are usually formed in pairs, while only a petiolate spikelet is formed at the tip of the rachis and each order rachis branch. Each spikelet has one floret covered by a pair of glumes and the floret consists of a lemma, a palea and floral organs, namely two lodicules, three stamens and a pistil. The developmental process of panicle formation excluding the vegetative stage was classified into five stages: formation of bract primordia (Stage 1), formation of primary rachis branches (Stage 2), formation of high order rachis branches (Stage 3). formation of spikelets (Stage 4) and formation of florets (Stagee 5). These developmental stages proceeded acropetally and not simultaneously. The developmental morphology of panicle obtained in this study should be useful to understand tiller formation with reference to canopy development.