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| Publication Type:
| Report |
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| Content Type: | Abstract or Summary only |
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| Author(s): | Lowe, D. B.;
Whitwell, T.;
McCarty, L. B. |
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| Author Affiliation: | Department of Horticulture, Clemson University, Clemson, SC 29634-0375 |
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| Title: | Temperature, light and nitrate influence seed germination of Green Kyllinga (Kyllinga Brevifolia), cock's comb kyllinga (K. Squamulata) and Tufted Kyllinga (K. Pumila) |
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| Section: | Weed management in turf, pastures and rangeland
Other records with the "Weed management in turf, pastures and rangeland" Section
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| Meeting Info.: | 52nd Annual Meeting, Greensboro, NC, January 25-27, 1999 |
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| Source: | Southern Weed Science Society Proceedings. Vol. 52, 1999, p. 73-74. |
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| Publishing Information: | Champaign, IL: Southern Weed Science Society. |
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| # of Pages: | 2 |
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| Keywords: | TIC Keywords: Temperatures; Light; Environmental factors; Nitrates; Seed germination; Kyllinga brevifolia; Kyllinga squamulata; Kyllinga pumila; Weed control
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| Abstract/Contents: | "Kyllinga species are becoming increasingly prevalent in turfgrass sites throughout North America. Developing effective, long-term weed management strategies requires knowledge of the weed's biology; therefore, parameters affecting weed seed germination should be studied. Three separate studies were performed to determine the effects of nitrate, temperature and light on green kyllinga, cock's-comb kyllinga and tufted kyllinga seed germination. Seeds were collected locally and surface sterilized (20% chlorox) for 10 minutes, rinsed, dried and stored at 24C. For all studies, 50 seeds of each species were placed into 50 mm petri dishes and irrigated with 2 ml of deionized water. Pads were kept moist throughout the 8-week studies. Gemination was counted weekly and seedings discarded upon radicle emergence. Experimental design for each study was a randomized complete block using 4 repetitions. ANOVA was utilized and means separated using LSD (P=0.05). Nitrate studies were performed in growth chambers maintained at constant temperature (25 C) and low light levels (12 hours/day at 12Ī¼mol mā»Ā² secā»Ā¹). Nitrate concentrations (0,50,200 and 400 mg Lā»Ā¹) were derived using potassium nitrate and deionized water. Temperature studies were performed in growth chambers maintained at 200Ī¼molā»Ā² sec ā»Ā¹ light. Temperatures alternated daily and treatments included 33/24, 25/17, 19 C day/11 C night temperatures. A subsequent temperature study was performed based upon results from the first study. The effects of constant temperature (25 C) versus diurnally alternating temperatures (25 C day/15 C night) were evaluated. The influence of light on Kyllinga seed germination was also investigated in growth chambers (12 hours/day at 12Ī¼mol ā»Ā² sec ā»Ā¹). Seed dishes were either left uncovered or covered with aluminum foil for 4 weeks. Foil was removed at 4 weeks and dishes remained in the growth chamber for an additional 2 weeks for subsequent rating. Nitrate did not influence Kyllinga seed germination but seedlings treated with nitrate were larger and greener at each rating than those placed in deionized water alone. Maximum green kyllinga germination (95%) occurred at 2 weeks but cock's-comb kyllinga seeds required 5 weeks for (95%) seed germination. Minimal (<10%) tufted kyllinga seed germination occurred throughout the study. Increasing temperature promoted Kyllinga germination percentage and rate. More than 90% green kyllinga seeds germinated in all temperatures; however, maximum germination occurred at 2, 3 and 5 weeks in 33/24, 25/17 and 19 C day/11 C night temperatures, respectively. Tufted kyllinga germination was statistically similar to green kyllinga in 33/24 C (89%) and 25/17 C (88%) but only 60% tufted kyllinga seeds germinated in 19/11 C by 8 weeks. Cock's-comb kyllinga germination was also similar to green kyllinga and tufted kyllinga in 33/24 C (87%), but was less than the other species in 25/17 C (74%) and 19/11 C (38%) by 8 weeks. Futhermore, cock's-comb kyllinga seeds did not initiate germination until 4 weeks in 19/11 C. In the second temperature study, alternating temperatures did not influence green kyllinga or cock's-comb kyllinga seed germination as >90% germination occurred for both species by 5 weeks. Tufted kyllinga, meanwhile, responded favorably to alternating temperatures as 87% seeds germinated in 25/15 C while only 7% seeds germinated in constant 25Ā° C. Temperatures fluctuate less in dense turfgrass than in weakened areas and tufted kyllinga may be a less competitive turfgrass weed than green kyllinga or cock's-comb kyllinga. Light was required for germination by each Kyllinga species. Green kyllinga, cock's-comb kyllinga and tufted kyllinga seeds in light germinated by 4 weeks (99, 97 and 35%, respectively); while those previously covered with aluminum did not germinate. Previously covered seeds resumed germination once they were placed in light so that similar germination percentages occurred for both treatments by 6 weeks. This is an important pest management strategy as a dense, uniform turf stand would minimize Kyllinga seed germination since minimum light penetration to the soil would occur". |
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| Language: | English |
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| References: | 0 |
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| Note: | This item is an abstract only! |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Lowe, D. B., T. Whitwell, and L. B. McCarty. 1999. Temperature, light and nitrate influence seed germination of Green Kyllinga (Kyllinga Brevifolia), cock's comb kyllinga (K. Squamulata) and Tufted Kyllinga (K. Pumila). South. Weed Sci. Soc. Proc. 52:p. 73-74. |
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