Effects of presence or absence of stems on nitrogen compounds of xylem sap of mulberry during regrowth after pruning

anatomia anatomie anatomy composition crops cultivation cultivo cultivos dicotiledoneas dicotyledons economic plants faisceau vasculaire feed crops haces vasculares methode methods moraceae morus nitrogen content plant anatomy plant vascular system plantas plantas forrajeras plante plante de culture plants poda pratique culturale pruning sap savia sistema vascular de la planta stems taille tallo tejido vascular teneur en azote tige tissu vasculaire urticales vascular bundles vascular tissues xilema xylem