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Grasses Family - Poaceae 1 AGR 4501 PASTURE MANAGEMENT Poaceae 2 family Poaceae (noun) - 1. the grasses: chiefly herbaceous but some woody plants including cereals; bamboo; reeds; sugar cane Synonyms: Gramineae, family Gramineae, Graminaceae, family Graminaceae, Poaceae, grass family AGR 4501 PASTURE MANAGEMENT Link to Poaceae 3 AGR 4501 PASTURE MANAGEMENT •includes food crops, pastures, turf, and important industrial crops. •Poaceae is the most important family of food crops, including the cereals, wheat Triticum, corn Zea and rice (Oryza). •Some members of the Poaceae form the dominant vegetation in warm and temperate regions where the rainfall does not support trees. 4 AGR 4501 PASTURE MANAGEMENT Features of Poaceae either annuals or perennials. alternate leaves with extended blades and clasping sheath stems, or culms, are normally hollow and round, and enclosed by leaf sheaths. all species have parallel leaf venation. 5 AGR 4501 PASTURE MANAGEMENT 6 AGR 4501 PASTURE MANAGEMENT Features of Poaceae (2) 7 flowers form a in a spikelet with a primary axis called the rachilla sepals and petals are absent; there are two glumes or bracts at the base of the spikelet, and each flower is usually enclosed in two further bracts, the lemma and palea. normally there are three stamens and only one pistil with two stigma the ovary is superior and contains one ovule forming an achene like fruit or caryopsis AGR 4501 PASTURE MANAGEMENT 8 AGR 4501 PASTURE MANAGEMENT 9 AGR 4501 PASTURE MANAGEMENT 10 AGR 4501 PASTURE MANAGEMENT Grass Morphology 11 AGR 4501 PASTURE MANAGEMENT 12 AGR 4501 PASTURE MANAGEMENT Ligules 13 AGR 4501 PASTURE MANAGEMENT Auricles 14 AGR 4501 PASTURE MANAGEMENT How grasses grow 15 New growth in grasses occurs in three different ways, from three different meristems or zones of growth. New tillers grow from axillary buds at the base of the plant, new leaves grow from apical meristems inside the stems, and intercalary meristems are secondary zones of growth at the base of the internode, sheath and blade. These are growth regions inserted between mature tissues. AGR 4501 PASTURE MANAGEMENT 16 AGR 4501 PASTURE MANAGEMENT Vegetative tiller A vegetative grass tiller. Leaf 1 is oldest and leaf 8 is just being exerted. The enlarged area of the crown shows the apical meristem that produces the leaves 17 AGR 4501 PASTURE MANAGEMENT Reproductive tiller A reproductive grass tiller. This tiller has a stem (or culm) and seedhead that differs from the tiller in Figure 1. Intercalary meristematic tissue at the base of the leaf blade, near the ligule (insert), allows for leaf expansion. 18 AGR 4501 PASTURE MANAGEMENT LEGUMES Family Leguminoseae 19 AGR 4501 PASTURE MANAGEMENT LEGUME legume , common name for any plant of the family Leguminosae, which is called also the pulse, legume, pea, or bean family. Botanically, a legume is the characteristic fruit of the pulse family plants, called also leguminous plants. It is a pod which usually splits along two sides, with the seeds attached 20 along one of the sutures. AGR 4501 PASTURE MANAGEMENT Features of Leguminoseae (Fabaceae) 21 Numbering about 650 genera and 17,000 species The leaves are usually compound; the fruit is a legume (a type of pod); and the blossoms may have an irregular butterflylike (papilionaceous) shape. Typically, the flowers have 10 stamens, and the corolla and the calyx are formed of 5 petals and 5 sepals, respectively. Some species have thorny branches. AGR 4501 PASTURE MANAGEMENT 22 AGR 4501 PASTURE MANAGEMENT 23 AGR 4501 PASTURE MANAGEMENT Link to typical legume plant 24 AGR 4501 PASTURE MANAGEMENT Nitrogen fixation 25 AGR 4501 PASTURE MANAGEMENT Why are legumes important? Each year legume-Rhizobium symbiosis generates more useful nitrogen for plants than all the nitrogen fertilizers produced industrially -- and the symbiosis provides just the right amounts of nitrogen at the right time at virtually no cost to the farmer. This symbiotic nitrogen fixation is very beneficial for two reasons: •it supplies the legume with nitrogen, •it can significantly decrease spending on N-containing fertilizers for the subsequent crops. 26 AGR 4501 PASTURE MANAGEMENT Role of Legumes Supply nitrogen to grasses Increased protein for ruminants (grasses 6-12%, legumes 15-30%) Increased minerals (P & K) for animals Improved digestibility of feed 27 AGR 4501 PASTURE MANAGEMENT Dry matter production per year Grasses 20-30 tonnes/ha C4 photosynthesis Resistant to grazing Legumes 15-20 tonnes/ha C3 photosynthesis Less tolerant to grazing 28 AGR 4501 PASTURE MANAGEMENT 29 AGR 4501 PASTURE MANAGEMENT