THE utility of interspecific and other remote crosses in breeding improved types is
well recognized. Extensive research aimed at increasing the degree of success in
such wide crosses has been undertaken in many countries. Investigations along
these lines in the Soviet Union have brought out the favourable influence on plant
growth of using a mixture of pollen, the influence of the amount of pollen in the
process of fertilization and the important role played by the carotin, carotinoids,
enzymes and other biologically active substances present in considerable quantities in
the pollen. It has also been shown that egg cells which have been fertilized by a
sperm and have begun to divide can be affected by other male gametes. Thus, by
successive pollination, first with unlabelled and subsequently with p32 and SS!!
labelled pollen, Polyakov and Dmitrieva (1955) were able to show, in tobacco,
makhorka and corn, that the labelled pollen also took part in the process of fertilization by influencing some metabolic processes. Pollen from an alien species was
also shown to have a definite influence. The technique of radioisotope labelling is
of interest to us here in that it enables us to determine the number of pollen tubes
which discharge their contents into one ovule during the process of fertilization.
Preliminary experiments indicate that the number is about 3-8 per ovule. The
results of these authors agree with our empirical conclusion reached on the basis of
several years' experience as to the influence of the application of varying quantities of
pollen in hybridization work.
Article DOI: NA
Print ISSN: 0019-5200
Online ISSN: 0975-6906
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