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Title: Studies on the reproductive biology of downy brome (Bromus tectorum)

Abstract

The ability of downy brome to successfully infest crop lands is partially due to its prolific nature. To better understand its reproductive biology, studies investigating (1) effects of temperature and photoperiod on flowering, (2) prevention of downy brome seed information with herbicides, and (3) effects of drought on reproduction, were conducted. Seedling vernalization was more effective than seed vernalization in promoting downy brome flowering. Vernalizing imbibed downy brome caryopses at 3 C for 0 to 30 days did not induce rapid flowering. Downy brome seedlings were exposed to six photoperiod/temperature treatments. After transfer to long days, plants from the short da/3 C treatment flowered within 30 days. DPX-Y6202 and fluazifop-butyl were tested for their ability to prevent seed formation in downy brome. Fluazifop-butyl prevented seed formation over a wider range of application rates and growth stages than did DPX-Y6202. Seed production was prevented most readily by herbicide applications made early in the reproductive cycle. Translocation of radiolabel was greater with /sup 14/C-fluazifop-butyl than with /sup 14/C-DPX-Y6202, particularly into developing spikelets. Microautoradiographic techniques were used to identify mechanisms involved in the prevention of downy brome seed formation by these herbicides. Tissue localization of both herbicides was similar. The highest concentration ofmore » radiolabel was found in developing pollen grains, suggesting that the herbicides prevented seed formation by interrupting pollen development or function. Water stress reduced apparent photosynthesis and increased diffusive resistance of flag leaves.« less

Authors:
Publication Date:
Research Org.:
Washington State Univ., Pullman (USA)
OSTI Identifier:
5117764
Alternate Identifier(s):
OSTI ID: 5117764
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; 59 BASIC BIOLOGICAL SCIENCES; GRASS; REPRODUCTION; TEMPERATURE EFFECTS; HERBICIDES; BIOLOGICAL EFFECTS; AUTORADIOGRAPHY; BIOLOGICAL STRESS; CARBON 14 COMPOUNDS; FLOWERS; MOISTURE; PLANT GROWTH; POLLEN; SEEDS; VISIBLE RADIATION; ELECTROMAGNETIC RADIATION; GAMETES; GERM CELLS; GROWTH; LABELLED COMPOUNDS; PESTICIDES; PLANTS; RADIATIONS 560203* -- Thermal Effects-- Plants-- (-1987); 560303 -- Chemicals Metabolism & Toxicology-- Plants-- (-1987); 551001 -- Physiological Systems-- Tracer Techniques

Citation Formats

Richardson, J.M. Studies on the reproductive biology of downy brome (Bromus tectorum). United States: N. p., 1986. Web.
Richardson, J.M. Studies on the reproductive biology of downy brome (Bromus tectorum). United States.
Richardson, J.M. Wed . "Studies on the reproductive biology of downy brome (Bromus tectorum)". United States. doi:.
@article{osti_5117764,
title = {Studies on the reproductive biology of downy brome (Bromus tectorum)},
author = {Richardson, J.M.},
abstractNote = {The ability of downy brome to successfully infest crop lands is partially due to its prolific nature. To better understand its reproductive biology, studies investigating (1) effects of temperature and photoperiod on flowering, (2) prevention of downy brome seed information with herbicides, and (3) effects of drought on reproduction, were conducted. Seedling vernalization was more effective than seed vernalization in promoting downy brome flowering. Vernalizing imbibed downy brome caryopses at 3 C for 0 to 30 days did not induce rapid flowering. Downy brome seedlings were exposed to six photoperiod/temperature treatments. After transfer to long days, plants from the short da/3 C treatment flowered within 30 days. DPX-Y6202 and fluazifop-butyl were tested for their ability to prevent seed formation in downy brome. Fluazifop-butyl prevented seed formation over a wider range of application rates and growth stages than did DPX-Y6202. Seed production was prevented most readily by herbicide applications made early in the reproductive cycle. Translocation of radiolabel was greater with /sup 14/C-fluazifop-butyl than with /sup 14/C-DPX-Y6202, particularly into developing spikelets. Microautoradiographic techniques were used to identify mechanisms involved in the prevention of downy brome seed formation by these herbicides. Tissue localization of both herbicides was similar. The highest concentration of radiolabel was found in developing pollen grains, suggesting that the herbicides prevented seed formation by interrupting pollen development or function. Water stress reduced apparent photosynthesis and increased diffusive resistance of flag leaves.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 1986},
month = {Wed Jan 01 00:00:00 EST 1986}
}

Thesis/Dissertation:
Other availability
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  • Developing and mature leaves of winter wheat (Triticum aestivum L. var. Daws) and the weed species downy brome (Bromus tectorum L.) were subjected to 10 mM (foliar application) and 1 mM (root application) herbicide solutions. Glyphosate (N-(phosphonomethyl) glycine) and atrazine (2-chloro-4-(ethyl-amino)-6-(isopropylamino)-s-triazine) were prepared in a carrier composed of 5% soybean oil concentrate, 35% acetone and 60% water. Penetration experiments with /sup 3/H-labelled herbicides assessed what percentage of herbicide entered leaves, and microautoradiography was used to determine qualitatively how much herbicide was present in the sections viewed with TEM. Tissue was excised at 4, 18, 62 and 200 hours, and thenmore » either freeze-substituted or fixed chemically. Ultrastructural effects of each herbicide on chloroplasts from leaves of newly-germinated seedlings and of well-tillered plants are depicted and discussed. Temporal differences in response of chloroplasts to each herbicide are noted.« less
  • Studies were conducted to investigate the metabolism of selenium (Se), and the influences of Se on the metabolism of cadmium (Cd) and inorganic mercury (Hg) in rats, and in ram semen in vitro. Se-deficient (-Se) or Se-adequate (+Se) rats were injected intraperitoneally with either /sup 109/CdCl/sub 2/ or /sup 203/HgNO/sub 3/. Semen ejaculates from yearling Suffolk rams were used for the in vitro studies. Whole-body retention of Cd and Hg in rats was significantly increased by Se. However, regardless of the Se status, the predominant route of Cd and Hg excretion was feces. Data on whole tissue Cd retention formore » both -Se and +Se rats gave the following order of decreasing tissue Cd levels: liver > kidney > testis > epididymis > seminal vesicles > prostate > brain. Cd and Hg concentrations ranging from 10/sup -6/ to 10/sup -2/ M were shown to be injurious to ram sperm in vitro as indicated by the depressed motility and reduced oxygen uptake.« less
  • A Micromonospora isolate, RV-101, obtained from the Red V Coconut Company in the Philippines, produces a new complex of antibiotics, the crisamicins. Using standard taxonomic methods for the genus Micromonospora, including micromorphology, growth characteristics on select media, whole cell analysis of chemical composition, and carbohydrate utilization patterns, the organism was classified as Micromonospora purpureochromogenes subsp. celinoensis. The chief character used in this classification was the production of a dark-brown diffusible pigment on media containing complex sources of nitrogen. The biosynthesis of crisamicin A was investigated by the technique of /sup 13/C acetate feeding and /sup 13/C NMR spectroscopy. Crisamicin Amore » was found to be synthesized from acetate via the polyketide biosynthetic pathway. In addition, the assignment of one of two possible structures, differing in the position of phenolic hydroxyl groups, and in the point of linkage between the two monomers of the molecule, was made using the labeling data. The structure determined demonstrates that crisamicin A is unique among the benzoisochromanequinone antibiotics, in that it lacks an oxygen atom at position C-8.« less