. Morphology of angiosperms (Morphology of spermatophytes. Part II). Angiosperms; Plant morphology. FERTILIZATION 153 small and oblong or lenticular on extrusion, the one passing to the polar nuclei increasing very much in size, the other very little. In Tricyrtis hirta Ikeda 58 found the male nucleus that passes to the polar nuclei showing " enormous change in size and shape " as it passes through the sac. There is usually more or less elongation of male nuclei at the time of discharge or afterward, but in Monotropa uniftora Shibata 54 has seen them elongated when entering the sac,
. Morphology of angiosperms (Morphology of spermatophytes. Part II). Angiosperms; Plant morphology. FERTILIZATION 153 small and oblong or lenticular on extrusion, the one passing to the polar nuclei increasing very much in size, the other very little. In Tricyrtis hirta Ikeda 58 found the male nucleus that passes to the polar nuclei showing " enormous change in size and shape " as it passes through the sac. There is usually more or less elongation of male nuclei at the time of discharge or afterward, but in Monotropa uniftora Shibata 54 has seen them elongated when entering the sac, but becoming more nearly spherical as fusion progresses. In the pollen-grain at the time of shedding the generative nucleus stains blue and the tube nucleus red with a combination like cyanin and erythrosin. This reaction is maintained, the male nucleus staining blue even after coming into contact with the nucleus of the egg which stains red; but as fusion proceeds the male nucleus takes less and less of the cyanin and finally stains with erythrosin like the nucleus of the egg. The fusion of the male and female nuclei may be very rapid, as observed by Guignard 4S' 53 in Zea and Itanuncula- ceae ; or the two may be long in contact without fusion, as noted by Johnson37 in Peperomia. The behavior of the chromatin during fusion has received but little attention. Mottier 28 fig- ures the chromatin when the nuclei are partly fused, and the statement is generally current that the nuclei fuse in the resting condition (Fig. 69). In view of the independence of the pater- nal and maternal chromatin dur- ing fertilization in Gynmo- sperms, as recently noted by several investigators, it would be well to reexamine the subject in Angiosperms, especially since most observers have paid little or no attention to this phase of the problem. Since it has been in connec- tion with fertilization and at- tendant phenomena that the cen- trosome problem has come into greatest prominence, it may not be i
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