Germination of pollen of the dwarf mistletoe Arceuthobium americanum

1991 ◽  
Vol 69 (3) ◽  
pp. 685-688 ◽  
Author(s):  
Jeannie Gilbert ◽  
David Punter

Pollen of Arceuthobium americanum Nuttall ex Engelmann, a parasitic dwarf mistletoe of Pinus banksiana Lamb, in Manitoba, was germinated on media containing a range of concentrations of sucrose and salts. Highest germination levels occurred on 20% sucrose agar; addition of salts significantly depressed germination. Pollen germinability was below 5% at first but increased to near 50% as the season advanced. Mean germination differed significantly between flowers from 10 staminate plants but peaked at approximately the same times in association with increasing temperatures. Freezing night temperatures were followed by reduced germinability. The optimum temperature for in vitro pollen germination is close to 30 °C, whereas 40 °C impairs germination. Key words: parasitic angiosperms, microclimate, jack pine, reproductive biology.

2021 ◽  
Vol 35 (3) ◽  
pp. 329-332
Author(s):  
Viktor Lyakh ◽  
Anatoliy Soroka

For the first time components of the nutrient medium were identified for the successful germination of pollen in such ornamental species of the Linum genus as L. grandiflorum, L. hirsutum, L. pubescens and L. thracicum. It was shown that the media with PEG-2000 in concentrations of 20-30% in combination with boric acid and calcium chloride in the concentrations of 200 mg/l ensure germination of Linum pollen up to 40-50%. The addition of sucrose and PEG with higher molecular weight adversely affects the germination of pollen. This will allow anyone to evaluate the quality of flax pollen quickly and efficiently and more successfully implement many genetic and breeding programs.


1990 ◽  
Vol 68 (5) ◽  
pp. 1163-1165 ◽  
Author(s):  
D. Eisikowitch ◽  
M. A. Lachance ◽  
P. G. Kevan ◽  
S. Willis ◽  
D. L. Collins-Thompson

The yeast Metschnikowia reukaufii is a natural contaminant of nectar and is vectored to the flowers of the field milkweed Asclepias syriaca by insects, some of which are pollinators of the plants. In its natural habitat, the yeast inhibits the germination of the milkweed's pollen, which normally uses nectar in the stigmatic cavity for germination. This inhibition is irreversible after about 8 h of exposure to the yeasts. Two selected strains of the yeast were isolated and investigated for their effects on pollen germination in vitro. The two strains, and their mixture, affected pollen germination adversely by reducing its amount and vigour and causing any pollen tubes that were produced to burst: One strain was more virulent than the other, and the mixture seemed to have an additive effect. The strains may be more efficacious than the natural assemblage of microbes in disrupting fertilization of milkweed flowers because they cause the immediate death (bursting) of the growing microgametophyte (pollen and tube). Key words: yeasts, pollen germination, milkweed, Metschnikowia reukaufii, Asclepias syriaca.


2012 ◽  
Vol 57 (1) ◽  
pp. 9-18 ◽  
Author(s):  
Dragan Nikolic ◽  
Vera Rakonjac ◽  
Milica Fotiric-Aksic

In this paper, during a 4-year period (2003-2006) effects of six pollenizers (President, Italian Prune, Stanley, Cacanska Rodna, Agen 707, and California Blue) on the degree of fruit set in the plum cultivar Cacanska Najbolja were examined. Besides the controlled pollination of this cultivar, open pollination was investigated. Functional pollen ability in pollenizer-cultivars was established by in vitro pollen germination. Degree of fruit set was determined comparing the number of fruit set (10 days after pollination, 21 days after pollination and number of harvested fruits) against the number of pollinated flowers. The results indicated that all pollenizer cultivars, studied in this paper, possessed satisfactory in vitro pollen germination (30.1-67.4%). The number of fruit set determined 10 days after pollination was very high and did not differ among pollenizers. Highly significant differences were found between the pollenizers in the number of fruit set 21 days after pollination and significant ones in relation to the number of harvested fruits. Compared to open pollination, higher number of fruit set 21 days after pollination and higher number of harvested fruits were obtained when cultivars Stanley (17.0%; 7.6%) and Italian Prune (14.6%; 6.9%) were used as pollenizers, therefore those cultivars are recommendable as good pollenizers for the cultivar Cacanska Najbolja.


2004 ◽  
Vol 118 (4) ◽  
pp. 595 ◽  
Author(s):  
Brock Epp ◽  
Jacques C. Tardif

The Lodgepole Pine Dwarf Mistletoe (Arceuthobium americanum Nutt. ex Engelm.) is an important pathogen of Jack Pine (Pinus banksiana Lamb.). Dwarf Mistletoe alters tree form, suppresses growth, and reduces volume and overall wood quality of its host. Stem analysis and a 3-parameter logistic regression model were used to compare the growth of heavily and lightly to non infected Jack Pine trees. At the time of sampling, no significant reduction in diameter at breast height and basal area were observed in heavily infected trees. However, a significant reduction in height and volume and an increase in taper were observed in heavily infected trees. Growth models predicted a 21.1% lower basal area, 23.4% lower height and 42.1% lower volume by age 60 for the high infection group.


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