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

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:
OSTI Identifier:
5117764
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: Thesis (Ph. D.)
Publisher:
Washington State Univ.,Pullman, WA
Research Org:
Washington State Univ., Pullman (USA)
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