Nature and development of plants . from themegaspore. Because this plant produces the male cells or malegametes we call it the male gametophyte. So we see that theflower forms two kinds of spores and that these germinate andform two kind> of plants, a male and a female. 53. Fecundation or A- soon a- the develop-ment of these two plants is completed a ven remarkable change takes place which starts an entirely new growth that is quiteindependent of the development Of the male and female gameto-phyte. The end of the tube cell becomes distended through theaccumulation of materia
Nature and development of plants . from themegaspore. Because this plant produces the male cells or malegametes we call it the male gametophyte. So we see that theflower forms two kinds of spores and that these germinate andform two kind> of plants, a male and a female. 53. Fecundation or A- soon a- the develop-ment of these two plants is completed a ven remarkable change takes place which starts an entirely new growth that is quiteindependent of the development Of the male and female gameto-phyte. The end of the tube cell becomes distended through theaccumulation of material ainl finally ruptures, discharging the male gametes into the female gametophyte. The chemical com-position of the female gamete is Buch that one of the male cellsi- attracted ; it (Fig. 80) and finally the two gametes unite NATURE OF PLANTS 109 forming a single cell. This body is a sexually formed spore orgametospore and like the ordinary spore has the power to germi-nate and produce a plant. The microspores and megaspores,. Fig. So. The micropylar end of an ovule of Canada lily (sectional view),showing the process of fertilization or fecundation. The tube, t, has growninto the female gametophyte and ruptured, discharging the two malegametes. One, c?, is seen fusing with the female gamete, ?, and the otherone, <$, is uniting with the two polar cells, thus forming the endospermnucleus; s, one of the synergids; i, integuments. however, were not formed by the union of sexual cells orgametes. Therefore we may distinguish them as asexual sporesor simply as spores. It has frequently been observed thatthe endosperm nucleus also attracts the other male gamete andcauses a similar fusion with it (Fig. 80). The union of the maleand female gametes is called fertilization or fecundation. Unlessfertilization is effected the growth outlined above practically endsthe history of the flower. But if fecundation is effected thena gametospore is formed that is capable of germinating andpr
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