摘要:

Summary.A rapid bioassay for diphenamid is described, based on differential elongation of oat roots after 48 h incubation, which can be used to assess the potency of diphenamid in solution or in soil. In sorption experiments using a slurry technique with soil: water ratios of 1: 2, 1: 3 and 1: 4, the bioactivity of the supernatant was similar for adsorption and release processes. The influence of soil characteristics on the bioactivity of diphenamid was determined by oat response in soil with herbicide and by oat bioassay on the supernatant after equilibration with soil. The results of direct and indirect assays corroborated each other and indicated that the organic matter content of the soil was the main factor affecting bioactivity.

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00990.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.In a series of foliar spray treatments on the deciduousAcacia drepanolobiumSjöstedt, a mixture of picloram+2,4‐D lulled a large proportion of the trees in May, the latter part of the principal rainy season, moderate numbers in November‐December, the subsidiary rains, and small numbers during the two intervening dry seasons. An ester formulation of 2,4,5‐T was generally less effective, but similar seasonal variations in kill occurred. At the time of maximum susceptibility, the rate of shoot extension growth was declining and new leaves were fully extended, but still succulent.With the evergreenTarchonanthus camphoratusL., the effectiveness of spraying was related directly to the growth rate of the shoots. The percentage kill was highest following application of picloram+2,4‐D in May‐July, the late long rains and first half of the long dry season, but low during the November‐December rains and short dry season.T. camphoratusis susceptible to foliar herbicide treatment over a longer period thanA. drepanolobium, presumably because of its different seasonal growth cha

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00991.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.Seeding ofAgropyron repens(L.) Beauv. undAgrostis giganteaRoth were grown in two photoperiods and with amounts of nitrogen. On two occasions plants transferred between photoperiods.The early growth of the seedlings was increased most by increasing the light intensity, but later nitrogen had the greatest effect. In short photoperiods, plants of both species were decumbent and had many more shoots than in long photoperiods. At the end of the experiment, plants of both species responded more to nitrogen in bright than in dim light, and the dry weight ofAgropyronwas increased more than that ofAgrostisby increased photoperiod and nitrogen.Agropyroninitiated rhizomes sooner thanAgrostis; it had fewer rhizomes but they were longer and thicker and weighed more. Brighter light, longer photoperiod and nitrogen all increased rhizome weight. Photoperiod did this mainly by producing more rhizomes, light by increasing thickness or density, and nitrogen by both. The effects of photoperiod and nitrogen on the rhizome dry weight ofAgropyron, but not ofAgrostis, were additive.Transferring plants from short to long photoperiods or from long to short, respectively increased or decreased total growth, but had an opposite effect on the rhizomes.

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00992.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.Seeds ofAgropyron repens(L.) Beauv, have little innate dormancy and germinate mainly during autumn, but germination may be delayed by cold, inadequate moisture or deep burial. Seedlings emerged from all viable seeds sown 5 cm deep but from only 4% of those 10 cm deep. Many seeds are viable when green and immature. At Rothamsted, spike emergence and flowering were earlier in 1970 than in 1968 and 1969 but more seeds became viable more rapidly in 1969. Higher temperatures in May and early June in 1970, and after flowering in 1969, probably account for most of these differences. Germination is facilitated by a diurnal alternation of temperature, but more old than young seeds can germinate at a constant temperature.

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00993.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.Wheat and barley treated with the butoxyethyl ester of 2,4‐D at 2, 4 and 8 kg/ha (a.e.) at the jointing stage of growth were analysed for the amino‐acid composition of the protein of the grain. A slight decrease in the threonine and arginine, and an increase in the proline content of wheat protein were observed. In barley, only methionine showed a slight increase as a result of herbicide treatment. No significant difference in the amino‐acid composition of the protein was found in grain from hand‐weeded and un‐weeded plots. High doses of 2,4‐D may increase the protein percentage, but have only a very minor effect on the amino‐acid composition o

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00994.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00995.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00996.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00997.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Cirsium arvense(L.) Scop. is a persistent and troublesome weed which reproduces vegetatively. Establishment from seeds (achenes) is considered negligible under natural conditions in the United Kingdom (Bates, 1946), although germination under normal farm conditions was found to be good in America (Hansen, 1918). Korsmo (1930) in Norway and Hayden (1934) in Iowa found that the seeds had no dormancy period, but Niethammer (1934) and Zilke (1967) recorded seed dormancy in Germany and South Dakota respectively. An examination was therefore made of some of the factors which may regulate the germination of seeds ofC. arvensein this country.

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00998.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00999.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY