The effect of self-, cross-, and no pollination on ovule, embryo, seed, and cone development in western red cedar (Thujaplicata)

1990 ◽  
Vol 20 (1) ◽  
pp. 66-75 ◽  
Author(s):  
John N. Owens ◽  
Anna M. Colangeli ◽  
Sheila J. Morris
Keyword(s):  
Seed Set ◽  
Ovule Development ◽  
Embryo Abortion ◽  
Red Cedar ◽  
Developing Seed ◽  
Stage Of Development ◽  
Cone Development ◽  
History Of ◽  
Nuclear Stage ◽  
Western Red Cedar

The effects of self-, cross-, and no pollination on cone size, filled seed, pollination efficiency, ovule development, and seed efficiency were tested on rooted ramets of six western red cedar (Thujaplicata Donn) clones. To fully develop, ovules must be pollinated with viable pollen and cones must have a minimum of one developing seed. The seed potential was constant among clones and not affected by pollination. The greatest loss of potential seed resulted from a failure of ovules to be pollinated, followed closely by the low percent viability of pollen. Unpollinated ovules aborted at the megaspore or free-nuclear stages. Pollinated ovules may abort at any stage of development, but it was most common during the long free nuclear stage. Selfing had a limited effect on postzygotic loss owing to embryo abortion or on seed set. Western red cedar is well adapted for a high degree of selfing. Clonal differences occurred in seed efficiency and stages at wich seed losses were most commun. Seed set in western red cedar may be increased if cones on female parents having a history of high seed efficiency are pollinated several times within a 1 week peak pollination period with abundant pollen of known high percent viability. Potential seed losses are discussed with reference to pollination and ovule development.

The relationship between time of pollination, pollination efficiency, and cone size in western red cedar (Thuja plicata)

1990 ◽  
Vol 68 (2) ◽  
pp. 439-443 ◽  
Author(s):  
Anna M. Colangeli ◽  
John N. Owens
Keyword(s):  
Developmental Stage ◽  
Positive Relationship ◽  
Mature Seed ◽  
Thuja Plicata ◽  
Pollination Efficiency ◽  
Red Cedar ◽  
Cone Development ◽  
Western Red Cedar ◽  
The Relationship ◽  
Thuja Plicata Donn

The pollination mechanism in western red cedar (Thuja plicata Donn) is described for container-grown clones. The seed cones ended dormancy at the end of February 1986, opened exposing the ovules, and soon after secreted pollination drops. Unpollinated cones remained open and secreted pollination drops for 15 to 20 days, before the expansion of the bract scales completely covered the ovules. The presence of pollen hastened cone closure so that it occurred within 4 or 5 days of pollination. Pollen in the micropyle was essential for ovule maturation and subsequent cone development. The developmental stage of the seed cones at pollination influenced the proportion of ovules per cone containing pollen (pollination efficiency). Each cone bore between 13 and 16 ovules. The proportion of ovules per cone that received pollen in the micropyles was highest when pollinations were conducted after cone opening but before bract scale expansion. A positive relationship was found between pollination efficiency and the length of mature seed cones.

Factors affecting seed set in Douglas-fir (Pseudotsuga menziesii)

1991 ◽  
Vol 69 (2) ◽  
pp. 229-238 ◽  
Author(s):  
John N. Owens ◽  
Anna M. Colangeli ◽  
Sheila J. Morris
Keyword(s):  
Reproductive Success ◽  
Pseudotsuga Menziesii ◽  
Low Temperatures ◽  
Seed Set ◽  
Douglas Fir ◽  
Ovule Development ◽  
High Moisture ◽  
Embryo Abortion ◽  
Factors Affecting ◽  
Major Loss

Cone and seed development in Douglas-fir were studied from pollination until seed release in 1986. Cone abortion at, and shortly after, pollination was high, resulting from a combination of low temperatures and possibly high moisture and populations of microorganisms on cones. Seed potential averaged about 75 seeds per cone with 31 filled seed per cone, giving an average seed efficiency of 39%. The major loss of seed resulted from insufficient pollen in the ovules. Other causes were ovule and embryo abortion at various stages of development. The effects of prezygotic and postzygotic events on seed set are discussed with respect to the reproductive success of Douglas-fir. Key words: Douglas-fir, seed set, cone, ovule, development, abortion.

Aqueous Leachate from Western Red Cedar: Effects on Some Aquatic Organisms

1976 ◽  
Vol 33 (12) ◽  
pp. 2703-2709 ◽  
Author(s):  
G. B. Peters ◽  
H. J. Dawson ◽  
B. F. Hrutfiord ◽  
R. R. Whitney
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Aquatic Organisms ◽  
Field Studies ◽  
Water Soluble ◽  
Free Swimming ◽  
Red Cedar ◽  
Stage Of Development ◽  
Western Red Cedar ◽  
Aqueous Leachate

Water-soluble extractives from western red cedar heartwood, bark, and foliage were investigated for their toxicity to aquatic organisms. The heartwood lignans and bark extractives were found to be moderately toxic, but the foliage terpenes and heartwood tropolones were more toxic, causing 50% mortality to coho salmon (Oncorhynchus kisutch) fry at 0.33 and 2.7 mg/liter, respectively. Tropolones were significantly less toxic to invertebrates than to free-swimming stages of the fish tested. Fry were found to be the stage of development of coho salmon (O. kisutch) most sensitive to the tropolones, and eyed eggs the least sensitive. Sensitivity of the coho fry to tropolones was moderated by previous sublethal exposure or the presence of a chelatable cation. Results from field studies and a leaching study indicate that directly releasing cedar leachate from landfills or allowing logging debris to enter streams should be avoided.

STUDIES IN THE LIFE HISTORY OF TRACHYCHELE BLONDELI MARS. (COLEOPTERA)

1927 ◽  
Vol 59 (9) ◽  
pp. 201-204
Author(s):  
Geo. R. Hopping
Keyword(s):  
British Columbia ◽  
Life History ◽  
Egg Laying ◽  
Red Cedar ◽  
History Of ◽  
Western Red Cedar ◽  
Seasonal History

In connection with the investigative work on Trachychele damage to western red cedar, it became expedient to make a study of the life history of the species, Trachychele blondeli Mars., which has become very troublesome to pole operators on the Coast of British Columbia. Accordingly a study of the life history was started by the writer in 1925. In the fall of that year and during the spring and summer of 1926, the seasonal history was studied and observations were made on emergence, egg laying, and breeding habits. The exact length of time spent in the larval state is still uncertain.

Mass and nutrient content of woody debris and forest floor in western red cedar and western hemlock forests on northern Vancouver Island

1993 ◽  
Vol 23 (6) ◽  
pp. 1052-1059 ◽  
Author(s):  
Rodney J. Keenan ◽  
Cindy E. Prescott ◽  
J.P. Hamish Kimmins
Keyword(s):  
Forest Floor ◽  
Forest Type ◽  
Woody Debris ◽  
Nutrient Content ◽  
Vancouver Island ◽  
Western Hemlock ◽  
N Availability ◽  
Red Cedar ◽  
The Mean ◽  
Western Red Cedar

Biomass and C, N, P, and K contents of woody debris and the forest floor were surveyed in adjacent stands of old-growth western red cedar (Thujaplicata Donn)–western hemlock (Tsugaheterophylla (Raf.) Sarg.) (CH type), and 85-year-old, windstorm-derived, second-growth western hemlock–amabilis fir (Abiesamabilis (Dougl.) Forbes) (HA type) at three sites on northern Vancouver Island. Carbon concentrations were relatively constant across all detrital categories (mean = 556.8 mg/g); concentrations of N and P generally increased, and K generally decreased, with increasing degree of decomposition. The mean mass of woody debris was 363 Mg/ha in the CH and 226 Mg/ha in the HA type. The mean forest floor mass was 280 Mg/ha in the CH and 211 Mg/ha in the HA stands. Approximately 60% of the forest floor mass in each forest type was decaying wood. Dead woody material above and within the forest floor represented a significant store of biomass and nutrients in both forest types, containing 82% of the aboveground detrital biomass, 51–59% of the N, and 58–61% of the detrital P. Forest floors in the CH and HA types contained similar total quantities of N, suggesting that the lower N availability in CH forests is not caused by greater immobilization in detritus. The large accumulation of forest floor and woody debris in this region is attributed to slow decomposition in the cool, wet climate, high rates of detrital input following windstorms, and the large size and decay resistance of western red cedar boles.

Influence of nursery culture on western red cedar

New Forests ◽  
1994 ◽  
Vol 8 (3) ◽  
pp. 231-247 ◽  
Author(s):  
Raymund S. Folk ◽  
Steven C. Grossnickle ◽  
John E. Major ◽  
James T. Arnott
Keyword(s):  
Nursery Culture ◽  
Red Cedar ◽  
Western Red Cedar

CORRELATED RESPONSE IN BROWN SARSON

1970 ◽  
Vol 12 (4) ◽  
pp. 905-913 ◽  
Author(s):  
T. Swamy Rao
Keyword(s):  
Gamma Irradiation ◽  
Seed Set ◽  
Previous History ◽  
The Self ◽  
Correlated Response ◽  
History Of ◽  
Self Compatibility ◽  
Selection For ◽  
Direction Opposite ◽  
Brown Sarson

The correlated response with changes in self-compatibility in three varieties of brown sarson subjected to gamma irradiation was examined. Selection for improved seed set in the irradiated populations showed that substantial correlated response can result for a constellation of other characters in which the self-compatible and self-incompatible forms differ. The correlated response was in a direction opposite to that of the previous history of selection.

National Library of Uzbekistan: from the history of formation and the current stage of development

Infolib ◽  
2020 ◽  
Vol 24 (4) ◽  
pp. 2-8
Author(s):  
Umida Teshabaeva ◽  
Keyword(s):  
New Technologies ◽  
Public Library ◽  
National Library ◽  
Stage Of Development ◽  
The World ◽  
History Of ◽  
The Republic ◽  
Favorable Conditions ◽  
History Of Formation ◽  
Current Stage

The article is devoted to the history of the Tashkent Public Library, at the origins of which were prominent scientists of that time, to the present day of the National Library of Uzbekistan. The library fund has more than 7.5 million items in 75 languages of the world. The National Library is the main methodological center of information and library institutions of the Republic. Creation of favorable conditions for readers is one of the priority tasks of the library, which is improved every year by the introduction of new technologies for obtaining information in an operational way. Thanks to membership in the International Consortium «eIFL», users have access to 38 foreign educational databases, 12 of which are licensed. Also, library readers get access to national and world educational collections in different languages of the world.

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