They are greater plants due to the fact that of true root, stem, branches, flower, reproductive organs and complicated vascular system.The vegetative offal are connected in the absorb of water and minerals, to produce of food, that utilization because that growth and also development.In part reproduction.Flowers room reproductive offal which differ in size, kind and shade from species to species.The sporophyteThe angiospermic tree is diploid (2n) and also a sporophyte.It is leading phase that the life cycle.It develop two morphologically and physiologically different kind the spores, the microspores (male-spore) and megaspores (female-spore).Flowes room reproductive organs.Structure of a common flowerAs we know, every flower is composed of four types of floral leaves: the sepals, petals, stamens and also carpals, i ordered it in whorls on receptacle.The sepals and also petals collectively known as perianth.The stamens and carpals are male and also female sporophyll respectively.They are very modified reproductive floral pipeline in i m sorry spores room produced.Microsporophyll(stamens)It consists of a stalk.the filament,and a bilobed structure at the tip, known as anther.The anther lobes are linked with a tissue, the connective.Two microsporangia are existing in each anther in i m sorry microspores produced.It is surrounding by many-layered sporangium wall surface that surround the sporogenous cells. The innermost layer which is nutritive in nature and also known together taptum.The cell divide to type microspore mother sells which undergo meiosis to produce tetrads of microspores The microspores germinate to form male gametophyte.MicrosporeEach microspore is unicellular, uninucleate structure possessing 2 layered wall.The external layer is thick and also called as exine and also inner is thin and also known together intine.Germ pores are present in the thin areas of exine layer.The exine listed with spinous outgrowth or reticulation in some cases.Megasporophyll(carpel)Each megasporophyll or carpel has a basal swollen part, the ovary; a stalk is existing at the top of the ovary, the style and stigma,the different modified reminder of the style.The stigma is the receptive portion which obtain pollen grains.OvuleThe ovary has actually one or an ext rounded or oval bodies, which are dubbed ovules.The ovules are created on the wall surfaces of ovary by unique tissue, the placentae.Each ovule is attached come the placenta by a short stalk, the funicle.The hilum is the location of attachments of the funicle come the key body of the ovule.The key body is composed of sporogenous tissue, the nucellus, spanned by 2 protective great the integuments. The integuments execute not surround the whole nucellus.A tiny opening is existing at the top.The junction the the nucellus and also integument is known as chalaza.A nucellus cell enlarges in size and also actsas megaspore mom cell.It divides meiotically to create linear tetrad that megaspores. The upper three spores disintegrate and the continuing to be one enlargeto form embryo sac.The GametophyteThe gametophyte phase is haploid much reduced and also dependent upon sporophyte.The microspores and also megaspores construct into male and female gametophyte respectively.Male GametophyteThe an initial cell of the male gametophyte is microspore.It is stood for by pollen seed which is semi germinated masculine gametophyte and also pollen tube through two sperms nuclei and also a pipe nucleus.The germination of the microspore starts while the is tho in the microsporangium. The cell core divides to form a generative and a vegetative nucleus.The intine prosper up with germ spicy to form pollen tube.At semi-germinated problem the microspore now dubbed pollen grain.The pollen grains lugged to the stigma the the carpel by wind, animals, water and insects.The move of pollen seed from anther come stigma is referred to as pollination.Then the pollen grains germinates here completely.The generative cell nucleus divides into two to kind sperm nuclei and also the pollen pipe which bring the sperm come the egg cell.Female Gametophyte
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The excess food is stored in the seeds.such as in pea, bean and gram. Tese seeds are well-known as endospermic seeds.Sometimes the endosperm is totally used by occurring embryo are recognized as non-endospermis seeds.The seedThe ripened ovule is dubbed seed.Some seeds are dicot(2cotyledons) and somes room monocot(1 cotyledon)The FruitThe ripened ovary is known as fruit.In angiospermic tree the seeds are enclosed in the fruits.The seed germinates as soon as conditions come to be favourable.Alternation the GenerationThere room two type of generations sporophyte and also gametophyte are current in the life bicycle of angiosperm tree which alternate with each other in continuous sequence.The reduction department is occurs during the formation of spore i beg your pardon is restored at the moment of development of zygote.