摘要:

Summary:Experiment conducted in the glasshouse with water hyacinth plants in pots revealed that 3h.after spraying parquet or 2.4‐D at recommendeb herbicida rates, 43 to 53, of the herbicide is found in the plants and the rest is present in the water culture Out of the total [14Clparaquat applied,38,9,8·8. 32 and 0.9% was found in the leaf blads. petioles, underwater foliage and roots respectively. The corresponding values for [14C]2, 4‐D were 320. 94. 13 and 0.2% As the time interval after spraying increased, a greater accumulation of herbicide in the under‐water parts was evident A net loss of 14 and 60%. of the applied 2,4‐D was recorded 1 and 2 weeks after spraying respectively the rate of paraquat loss from the plant water system was similar to 2,4‐D.Absorption of [14C]2,4‐D from the culture solution by the roots and the floats of the water hyacinth was. evident Translocation of root‐absorbed 2, 4‐D into the meristematic folrar parts was dernonstrated If the substrates was treated with 2,4‐D.a minimal concentration of 1 p. p. m. was required for water hyacinth death In another experiment glyphosite at 2 to 6 kg a 1 ha and 2.4‐D.amine at 0–75 2.25 kg a ha gave complete control of water hyacinth Asulam was found to be unsatis factory even at 6 kg a.1 ha

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1979.tb01510.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Summary:Four field experiments were conducted at The International Rice Research Institute during the 1975 and 1976 crop seasons to develop minimum and zero tillage techniques for transplanted rice (Oryza sativaL.). High rates of glyphosate followed by a lower rate of paraquat effectively controlledPaspalum distichumL., but notFimbristylis littoralisL. The tenminimum tillage treatments based on different combinations and sequences of pre‐plant herbicide application, tillage and flooding, gave a similar grain yield to conventional tillage, and significantly higher grain yield than zero tillage treatments. Conventional, minimum and zero tillage were compared over four successive crops. After two crops with zero tillage, the plots were dominated by the perennials,P. distichumandScirpus maritimusL., but with minimum or conventional tillage, weed control and grain yield were satisfactory. Efficiency of nitrogen fertilizer usage by the crop was the same with minimum as with conventional tillage but higher than with zero tillage and was increased by placement at 10 cm depth. The studies indicate that minimum tillage systems are a dependable alternative to conventional tillage for lowland rice productio

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1979.tb01511.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Summary:This paper describes a field experiment conducted in north‐east Victoria investigating the control ofEchium plantagineumL. in a pasture with 2, 4–D and grazing management.Spraying with a small dose of 2, 4‐D (0–14 kg a.i./ha) in late autumn/early winter, followed about 2 weeks later by heavy grazing, removedE. plantagineumfrom the pasture, whilst the associated pasture species,Trifoliutn subierraneumL., was retained. Continuous grazing without spraying also resulted in good control ofE. plantagineum.Herbage production of the pasture in winter was, however, reduced by spraying. The reasons underlying these observations, and farm management programmes for the longterm control ofE. plantagineum, are di

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1979.tb01512.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Summary:Soil core samples taken from a sandy loam soil at Woburn during January 1972, following spring beans during the previous year, indicated that half the rhizome dry weight ofEquisetum arvense(L.) occurred in the uppermost 25 cm of soil and 10% between 75 and 100 cm. Tubers occurred relatively more deeply with half the number and three‐quarters of the weight deeper than 50 cm. However, after a 2‐year fallow 80% of the rhizomes and tubers were in the uppermost 25 cm of soil. In general, the weight of individual tubers increased with increasing depth in the soil. In pots in the glasshouse, tubers that were formed in one season lost weight when new shoots emerged in the following year; those formed during summer germinated readily in warmth indoors when detached in the autumn, but not until June of the following year in the field. Burial of tubers at a range of depths down to 25 cm did not affect the number of shoots emerging but emergence was delayed.Plants made more growth in neutral than in acid or basic soil, more in silty clay loam than in sandy loam and appeared well adapted to growth in soils with little nitrogen. In general, rhizome growth was less affected by variations in pH and nitrogen level than were shoots and tubers. Plants grown from tubers were suppressed greatly by wheat sown densely and given a moderate amount of nitrogen fertilizer but had negligible effect on the wheat. With fewer wheat plants given less nitrogen, the species partitioned more of its assimilate into tubers than when it was grown alone.The significance of tubers in the biology of the species is briefly discussed and areas meriting further study are highligh

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1979.tb01513.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Summary:The response, of cell suspension and callus cultures of celery to asulim (6–600 μmoll−1) in the nutrient medium was compared with that of seedlings. The callus cultures were treated.at three slages of differentiation: undifferentiated callus, differentiated callus on which embryoids had developed to the globular and heart‐shaped stage, and finally plantlets which had secondary leaves and roots. Cell division in the suspension culture was enhanced at low concentrations (6 and 12 μmoll−1) and inhibited at higher concentrations Cell expansion was unaffecte by the presence of asulam In differentiated tissue the growth stimulation at low concentrations was absent. and there was a steady decline in accumulation of fresh weight with increasing concentration. Root length and number of laterals of intact seedlings showed a similar pattern, indicating that the response of the tissue to asulam was not radically altered by diffe

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1979.tb01514.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Summary:Application of N‐(phosphonomethyl) glycine or GLY'PHO‐SATE to couch grass Pancum repens (L) Beauv. resulted in an intitial increase of the total amino acid content in the plant. which reached a maximum on the 8th day following treatment This was most marked in the rhizomes where the value was about three times that of the control plants. The initial increase fell off rapidly with time and on the 15th day after application the total amino acid content of the treated leaf and rhizome samples was less than the controls Resurgence of rhizome activity was noticeable on about the 48th day (viz. 7 weeks after t he Ist applicati

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1979.tb01515.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Summary:Plants of wild myrtle (Myrtus communisL.) collected at full bloom contained substances inhibitory to the germination and seedling growth of perennial ryegrass. (Lolium perenneL. cv Hollandi)Tissue suspensions had a greater inhibitory activity than water extracts of the plant tissue. Boiling the plant material also increased the inhibitory activity of suspensions and extracts. Flower, and buds, fruit covers and leaves had the greatest inhibitory effect/unit weight ot tissue but inhibitory activity was also present in stems and roots at lower concentrations.The effect of myrtle leaf suspensions on germination of seed of thirteen common garden flowers was also examined: Germination ofPetunia. Antirrhinum, Liaum. CheiranthusandLathyruswas inhibited completely or substantially depressed. Germination ofZinnia, Tagrtes. VerbenaandDianthuswas not much affected, while that ofBrllis. Gaillardia. andViolawas affected to an intermediate extent.These results suggest that the possible use of wild myrtle as an evergreen hedge plant needs to be examined further because of possible interference with the growth of nearby lawns and flowers.

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1979.tb01516.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Summary:The uptake of 2,4,5‐T by spines of gorse (Ulex europaeusL.) was limited and not enhanced when picloram was added to the application solution. Translocation of 2,4,5‐T in 6‐month‐old cuttings after treatment of a single spine or lateral branch was poor. The most significant accumulation of translocated herbicide occurred in stem tissue, with lesser amounts detected in root tissues, root nodules, stem apices and flowers. Untreated lateral branches or spines accumulated minimal amounts of herbicide. The pattern and extent of distribution of 2,4,5‐T was not increased by addition of picloram. The lack of efficient control of gorse by 2,4,5‐T can largely be attributed to its inadequate uptake and lack of true systemic tr

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1979.tb01517.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Summary:Chlorophyll production by wheat (Triticum aestivumL. ‘Mericopa’) and corn (Zea maysL. Merit) was severely curtailed by the experimental herbicide l‐(m‐trifluoromethylphenyl)‐3‐chloro‐4‐chloromethyl‐2‐pyrrolidone (R‐40244). A 96% loss in chlorophyll content was observed in wheat seedlings treated with 320 μmol/1 R‐40244. In corn 320 μmol/1 R‐40244 caused a 40% drop in chlorophyll content. Carotenoid production in both wheat and corn was inhibited by R‐40244, 320 μmol/1 of the herbicide causing a 97% reduction in wheat and a 44% reduction in corn. The inhibition of carotenoid production which, in turn, allows chlorophyll to be photooxidized, may represent the mode of action of R‐40244. Hill reaction activ

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1979.tb01518.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Summary:Inhibition of photosynthesis by metamitron in the rooting medium and its subsequent recovery after transfer of the roots to herbicide‐free nutrient solution was measured in eight plant species.Fast and complete recovery within a few hours after treatment showed that metamitron, once absorbed, was rapidly and completely inactivated in the leaves of sugar beet (Beta vulgarisL.). Inactivation in perennial ryegrass (Lolium perenneL.) was slower and incomplete. It was low inEchinochloa crusgalli(L.) P.B.,Amaranthus retroflexusL.,Alopecurus myosuroidesHuds. and bean (Phaseolus vulgarisL.), and undetectable in maize (Zea maysL.) andPortulaca oleraceaL.From the transpiration rate and the concentration of metamitron in the nutrient solution that just did not cause inhibition of photosynthesis in sugar beet, uptake and inactivation rates per unit leaf area were calculated to be at least 18·5 ng/cm2/h. The same external concentration markedly depressed photosynthesis in the other more susceptible species.After leaf sprays sugar beet plants gradually resumed the normal rate of photosynthesis, but bean plants did not recov

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1979.tb01519.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY