摘要:

Summary.The effects of all combinations of five desiccation treatments, two temperatures and three durations of desiccation on the survival ofCyperus esculentustubers and two‐nodeCynodon dactylonrhizome fragments were examined in laboratory and glasshouse experiments.Cyperus esculentustuber survival was greater at 22°C than at 4°C. Duration of desiccation did not influence tuber survival, except at the lower temperature.Survival ofCynodon dactylonrhizome fragments was greatly influenced by desiccation treatment, duration of desiccation and the interaction of these two factors. No buds survived when rhizomes reached 50% of their original weight, indicating good tolerance of desiccation since the original dry‐matter content of rhizomes in this experiment was

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01442.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Summary.2,4‐D‐amine, 2,4‐D ethyl ester, 2.4‐DB‐potassium. MCPA‐sodium, diquat and a 1:1 mixture of 2,4,5‐T butyl ester and 2,4‐D ethyl ester were applied to the tropical pasture legumeCentrosema pubescensBenth. (centro) grown either alone or withPanicum maximum Jacq.(guinea grass). Even at 0.5 Ib/ac (total) the 2,4,5‐T/2,4‐D mixture caused severe damage to seedling and mature centro. 2,4‐D‐amine, 2,4‐D ethyl ester and 2,4‐DB‐potassium were less damaging and there were only slight differences in response to these. Diquat at 0.25 Ib/ac desiccated centro seedlings, but most plants survived and grew satisfactorily. There was some evidence that the growth of mature centro was depressed least when the herbicides were applied during vegetative quiescence.Application just after the start of flowering altered the flowering pattern but did not reduce seed yields significantly. 2,4‐D‐amine at 0.75 and 1–5 lb/ac and 2,4‐D ethyl ester at 1.5 Ib/ac decreased the percentage germination of abraded seed. Diquat 0.25 Ib/ac applied at the start of flowering caused significant increases in top growth and seed pod numbers, possibly the result of modific

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01443.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Summary.A bioassay was used to study, adsorption of prometryne, simazine, linuron and pyrazon by fibrous peat, sphagnum moss, muck soil and bentonite as 1 % mixtures with quartz sand. Of these bentonite caused least reduction in bioactivity, and sphagnum moss reduced it only slightly more. Fibrous peat and muck soil were the most adsorptive. Prometryne, simazine and pyrazon were more highly adsorbed by fibrous peat than by muck soil, while for linuron the opposite occurred. Fibrous peat was approximately three, seven, thirteen and three times more adsorptive than bentonite for pyrazon, linuron, prometryne and simazine, respectively, while for muck soil the corresponding values were two, fourteen, seven and two.Studies with prometryne and five different soils indicated that percentage organic matter, cation‐exchange capacity and specific surface area were all highly correlated with adsorptio

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01444.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Summary.Three box experiments examining the effects of shoot removal on rhizome carbohydrate reserves are reported.During summer in England the optimum frequency of hand defoliation for maximum loss of carbohydrate was 10–14 days. As in previous experiments, high levels of soil nitrogen sometimes increased the rate of carbohydrate loss from 9‐in. rhizome pieces. This result was obtained when nitrogen was supplied as a nitrate, an ammonium salt, or urea.Repeated applications of 2 or 4 oz/ac paraquat over a period of about 60 days reduced carbohydrate reserves to about 50% of the level obtained with the same number of hand clippings. It is suggested that paraquat may have been translocated to the rhizomes, the carbohydrate content of which may have been reduced by an effect of the paraquat on the respiration rate.When plants which had been subjected to different methods and frequencies of defoliation were uprooted and buried beneath 2 in. of soil, there was a connection between the rhizome carbohydrate content at the time of burial, the ability of the plants to regenerate, and the rate at which new carbohydrate reserves built up during the following two mon

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01445.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Summary.Prometryne, linuron and chlorpropham at concentrations between 10 and 100 ppm had only temporary effects on the growth of three strains of bacillus sp. type mesentericus in liquid culture; growth of Pseudamonas phaseoli was not affected. The sensitivity of Ps. phaseoli lo pure antibiotics was only slightly affected by the herbicides, hence the effects of the herbicides on the antagonism between the two organisms which were observed appeared to be attributable to disturbance of the metabolism oi Bacillus sp., and varied with the strain employed.

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01446.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01447.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Summary.The effect of the herbicidal compound dicamba (2‐methoxy‐3,6‐dichlorobenzoic acid) on the rate of oxygen uptake and on cell membrane permeability of leaf tissues of purple nutsedge (Cyprus rotundusL.) was studied. Dicamba induced noticeable alterations in both the pattern of oxygen consumption and in permeability of the cells following spraying of the foliar parts of the plants. A pronounced decrease in respiratory rate was observed 5 days after treatment with 10−3M dicamba, but the rate of oxygen uptake rose to approximately the level of the control 10 days after application of the herbicide. Permeability of the cell membranes decreased 5 days after treatment of the leaves with 10−2M or 10−3M dicamba. The results indicate that the early disruption of the cell membranes might be related to the mode of action of th

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01448.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Summary.Similar chlorthal (dimethyl 2,3,.5,6‐tetrachloroterephthalate) degradation patterns were found in pot cultures of white pine and Monterey pine grown in a sandy soil and in fallow cultures of the same soil. After 120 days, the content of chlorthal plus its degradation products (as measured by14C‐activity) had decreased to 37% in the fallow and white pine cultures. A somewhat slower rate of degradation in soil (average 45%*C‐activity remaining) was observed for the Monterey pine cultures. Thus in 120 days, 55–63% of the added chlorthal had been lost from the soil system. A negligible amount of this could be accounted for by plant uptake. After 60 days of growth the rate of degradation in soil was greatly curtailed suggesting that the accumulated degradation produces were able to inhibit the further degradation of the herbicide.Analysis of *C‐labelled extracts from the pine tissue showed that uptake of chlorthal varied from 0–25 to 1–2% of the total amount of the chemical added to the soil. Degraded, as well as intact chlorthal, were found in both Monterey and white pine tissue. Very limited mobility of chlorthal in the plant was observed and the concentration in the shoots was less than 10 pm. About 80% of the absorbed chlorthal remained in the root systems. Plant growth led to a rapid dilution of absorbed chlorthal. The growth of both species of pine was rapid and apparently healthy in chlorthal‐treated soil and comparable to that of the

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01449.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01450.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01451.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY