Seed germination dynamics of silverleaf nightshade ( Solanum elaeagnifolium Cav.) and implications for effective weed management

Author(s):  
Nathaniel Jacob Turner ◽  
Jacobo Sanchez ◽  
Cody Vavra ◽  
Lakhvir K. Dhaliwal ◽  
Yves Emendack ◽  
...  
Weed Science ◽  
2016 ◽  
Vol 65 (1) ◽  
pp. 141-150 ◽  
Author(s):  
Wei Tang ◽  
Jie Chen ◽  
Jianping Zhang ◽  
Yongliang Lu

Triquetrous murdannia is an annual weed commonly found in rice fields in China. Laboratory and screenhouse experiments were carried out to determine the effect of light, temperature, osmotic and salt stress, seed burial depth, amount of rice residue, and depth of flooding on seed germination and seedling emergence of triquetrous murdannia and to evaluate the response of this weed to commonly available POST herbicides in China. Germination was greater than 93% under a wide day/night temperature range of 20/10 to 30/20 C in the light/dark regime. The time to onset of germination decreased as temperature increased. Germination was slightly stimulated when seeds were placed in light/dark conditions compared with seeds placed in the dark. The osmotic potential and NaCl concentration required for 50% inhibition of maximum germination were −0.5 MPa and 122 mM, respectively. The highest germination (68%) was observed from seeds sown on the soil surface, but decreased with increasing burial depth. Only 7% of seedlings emerged from a depth of 4 cm, and no seedlings emerged from seeds buried deeper than 6 cm. Seedling emergence decreased from 93 to 35% with increasing quantity of rice residue (1 to 6 103kg ha−1) applied on the soil surface. Seedling emergence was reduced by 40, 48, 64, and 70% at flooding depths of 1, 2, 4, and 6 cm, respectively, for the seeds sown on the soil surface. Fluroxypyr and MCPA herbicides provided 100% control of triquetrous murdannia at the 2- to 6-leaf stages; however, to achieve 100% control with bispyribac-sodium, MCPA+bentazone or MCPA+fluroxypyr, herbicides had to be applied by the 4-leaf stage. The results of this study could help in developing more sustainable and effective integrated weed management strategies for the control of triquetrous murdannia in rice fields in China.


Weed Science ◽  
2015 ◽  
Vol 63 (1) ◽  
pp. 312-320 ◽  
Author(s):  
Heino B. Papenfus ◽  
Manoj G. Kulkarni ◽  
Martin Pošta ◽  
Jeffrey F. Finnie ◽  
Johannes Van Staden

Weeds pose a great problem to farmers worldwide, and controlling weeds demands a high input cost for herbicides and labor. Because of current environmental regulations, a limited number of herbicides are commercially available (with limited modes of action) to control weeds. Smoke water and the biologically active compounds isolated from smoke affect seed germination in a significant way. Smoke water (SW) and karrikinolide (KAR1, the germination stimulant isolated from smoke) have been tested extensively for their ability to promote seed germination in a vast array of plant species. In addition to KAR1, a germination inhibitor, trimethylbutenolide (TMB), was also isolated from plant-derived smoke. The effects of SW, KAR1, and TMB were tested on five major weed species of South Africa: fleabane, hairy wild lettuce, bugweed, spilanthes, and fameflower. Seeds of these weed species were subjected to 16/8 h light/dark conditions or to constant dark conditions at constant temperatures of 20, 25, 30 C and alternating 30/20 C. SW and KAR1significantly increased germination, whereas TMB significantly inhibited germination of these weed species. Furthermore, TMB treatment reduced the amylase activity of the tested weed seeds compared with the water control. These results indicate the possibility of manipulating germination of certain weed seeds by SW, KAR1, and TMB. Thus, smoke and smoke-isolated compounds could potentially be used in new weed management strategies.


2018 ◽  
Vol 15 (4) ◽  
pp. 929-935 ◽  
Author(s):  
Nadi Awad Al-Harbi

The present study aims to evaluate the effect of leaf extract of Rhanterium epapposum and Salsola imbricata at various concentrations (20%, 40%, and 60%) on the germination and shoot and root lengths of two weed species; Portulaca oleracea and Chenopodium murale. The present study findings proved that the inhibitory effect of seed germination and shoot and root lengths of the studied species was largely dependent on the concentration of R. epapposum and S.imbricata leaf extract. The results showed that the highest allelopathic effect on the germination of the seeds of C.murale by leaf extract of R. epapposum and S. imbricata especially at concentration of 40% and 60% . While the lowest effect was of the leaf extract of S.imbricata. However the concentration of 60% was higher on the germination of the seeds C. murale and P. oleracea. Results also showed that the root and shoot lengths of C. murael was more sensitive to allelochemicals of R. epapposum leaf extract compared to S.imbricata leaf extract. However, the root and shoot lengths of P. oleracea was more sensitive to allelochemicals of S. imbricata leaf extract compared to R.epapposum leaf extract. Hence, the present findings recommended using the R. epapposum leaf extract and S. imbricata leaf extract as a tool for weed management especially C. murale and P. oleracea.


Weed Science ◽  
1982 ◽  
Vol 30 (3) ◽  
pp. 264-269 ◽  
Author(s):  
John W. Boyd ◽  
Don S. Murray

Plants started with seed, 'seedlings', and established plants of silverleaf nightshade (Solanum elaeagnifoliumCav.) were grown in the field under shade levels of 0, 47, 63, and 92% of full sunlight to determine vegetative, reproductive, and physiological responses to shade. Dry-matter production of both 'seedling’ and established plants declined markedly with increasing shade levels. Established plants did not bear fruit under 92% shade, and 63% shade prevented fruit production by 'seedlings'. Taproots of plants grown in full sunlight contained 16% more total non-structural carbohydrate (TNC) per gram dry weight than taproots of plants grown under 92% shade. Leaves of established plants grown under moderate shade had significantly more chlorophyll per unit leaf fresh weight than plants grown in full sunlight; however, plants under heavy (92%) shade had 35% less chlorophyll per unit leaf area than unshaded plants. The chlorophylla/bratio of the 92%-shaded plants was significantly less than with other treatments. Leaf area increased, with increasing shade; however, leaf weight per unit area decreased because of thinner leaves. Photosynthetic rates of recently expanded leaves were 10.4, 4.6, 3.3, and 0.9 mg CO2· dm−2· h−1for the 0, 47, 63, and 92% shade treatments, respectively.


Weed Science ◽  
1997 ◽  
Vol 45 (4) ◽  
pp. 488-496 ◽  
Author(s):  
Joseph O. E. Oryokot ◽  
Stephen D. Murphy ◽  
A. Gordon Thomas ◽  
Clarence J. Swanton

To predict weed emergence and help farmers make weed management decisions, we constructed a mathematical model of seed germination for green and redroot pigweed based on temperature and water potential (moisture) and expressing cumulative germination in terms of thermal time (degree days). Empirical observations indicated green pigweed germinated at a lower base temperature than redroot pigweed but the germination rate of redroot pigweed is much faster as mean temperature increases. Moisture limitation delayed seed germination until 23.8 C (green pigweed) or 27.9 (redroot pigweed); thereafter, germination was independent of water potential as mean temperatures approached germination optima. Our germination model, based on a cumulative normal distribution function, accounted for 80 to 95% of the variation in seed germination and accurately predicted that redroot pigweed would have a faster germination rate than green pigweed. However, the model predicted that redroot pigweed would germinate before green pigweed (in thermal time) and was generally less accurate during the early period of seed germination. The model also predicted that moisture limitation would increase, rather than delay, seed germination. These errors were related to the mathematical function chosen and analyses used, but an explicit interaction term for water potential and temperature is also needed to produce an accurate model. We also tested the effect of mean temperature on shoot elongation (emergence) and described the relationship by a linear model. Base temperatures for shoot elongation were higher than for seed germination. Shoot elongation began at 15.6 and 14.4 C for green and redroot pigweed, respectively; they increased linearly with temperature until the optimum of 27.9 C was reached. Elongation was dependent on completion of the rate-limiting step of radicle emergence and was sensitive to temperature but not moisture; hence, elongation was sensitive to a much smaller temperature range. Beyond mathematical changes, we are testing our model in the field and need to link it to ecophysiological, genetic, and spatially explicit population processes for it to be useful in decision support for weed management.


1991 ◽  
Vol 31 (2) ◽  
pp. 233 ◽  
Author(s):  
D Lemerle ◽  
AR Leys

The effect of controlling silverleaf nightshade with 2,4-D or glyphosate for 4 consecutive years on the yield of wheat was determined in a field experiment in southern New South Wales. Silverleaf nightshade was either controlled throughout summer with 2,4-D or glyphosate, or treated once with 2,4-D each February from 1979 to 1982. After 4 years, the initial density of silverleaf nightshade increased from 8 to 17 shootsJm2 in both the untreated controls and the plots treated with 2,4-D in February. Treatment throughout each summer with 2,4-D retarded this increase to 11.4 shootslm2, and treatment with glyphosate reduced the population to 1.6 shoots/m2. The grain yield of wheat was not affected by prior control of silverleaf nightshade in 1979 or 1980, but in 1981-82 there was a significant (P<0.05) yield increase from some herbicide treatments, compared with the unsprayed controls. In 1981, repeated application of glyphosate or 2,4-D increased yield by 14 and 9%, while the application of 2,4-D in February increased yield by 5%. In 1982, a drought year, the responses were much greater, with corresponding yield increases of 69, 49 and 17% from these treatments.


2013 ◽  
Vol 100 (12) ◽  
pp. 2307-2317 ◽  
Author(s):  
Geoffrey E. Burrows ◽  
Rosemary G. White ◽  
John D. I. Harper ◽  
Roger D. Heady ◽  
Rex A. Stanton ◽  
...  

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