The Detection and Nature of Dominant Lethals in Lilium. I. Effects of X Rays on the Heritable Component and Functional Ability of the Pollen Grain

Differential Seed Production in Mimulus guttatus in Response to Increasing Concentrations of Copper in the Pistil by Pollen from Copper Tolerant and Sensitive Sources

“…For example, exposure to air pollutants (Dueck et al, 1987) or heavy metals (Searcy and Mulcahy, 1985a;Dueck et al, 1987) did not appear to affect pollen tube growth in vivo. In addition, studies of pollen irradiated with either gamma irradiation (Pfahler, 1967;den Nijs and Van den Boom, 1983) or X-rays (Brown and Cave, 1954) have indicated very little difference in pollen tube growth rate or fertilization ability until doses were high.…”

“…The increased copper in the pistil may have affected individual pollen tubes so although fertilization occurred, the developing seeds subsequently aborted. Studies by Brown and Cave (1954), and den Nijs and Van den Boom (1983), have indicted that irradiated pollen can initiate seed development. However, although these seeds may contain endosperm, they usually lack an embryo and subsequently abort.…”

The Induction of Embryos and Tetraploid Endosperm Nuclei With Irradiated Pollen in Lilium

“…The division of the generative nucleus was inhibited in 99 % of L. regale pollen tubes after an exposure of 22 kR and the pollen tube growth of L. superbum was stopped between 200 and 205 kR (PRICE, 1957). Nonfusion as well abnormal divisions to give lobed nuclei or micro-nuclei in the embryo sac after fertilization were described by BROWN and CAVE (1954) to occur as a consequence of the pollen irradiation.…”

The Detection and Nature of Dominant Lethals in Lilium. Ii. Cytological Abnormalities in Ovules After Pollen Irradiation

“…DEVELOPMENT OF OVULES FERTILIZED BY IRRADI-ATED SPERMS.-Mitosis of the generative nucleus in the pollen tube is characterized by many irregularities. Nevertheless, the function of the male gametophyte is not impaired (Brown and Cave, 1954) because the tube continues to grow, enters the embryo sac, and each sperm associates itself with either the egg or the haploid polar nucleus.…”

“…After a specified number of days the ovaries were fixed in CRAF, embedded in paraffin, cut at 25 p., and stained with safranin and crystal violet. The region chosen for examination in each ovary was approximately 25 to 35 per cent of the distance from the top to bottom thus excluding the terminal regions of the ovary in which some seed abortion may occur normally (Brown and Cave, 1954).…”