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Variation of Parthenium hysterophorus in response to soil quality: implications for invasiveness 总被引：1，自引：0，他引：1
Summary The performance of Parthenium hysterophorus , native to the tropical Americas and invasive to several countries, was evaluated for response to soil quality. Phenological (six stages) and quantitative growth variables [relative growth rates in height (Rh ) and diameter (Rd )] were measured every fortnight. Based on harvest data, the variables, root:shoot (R:S) ratio, specific leaf area (SLA), relative growth rate in biomass (Rw ), net assimilation rate (NAR) and dry matter allocation to plant components, were determined. High clay content in soils prolonged the rosette stage, enhanced Rh and Rd and hampered root growth, but promoted biomass allocation to shoots. The extreme degree of plant mortality was observed, with only 33.3% individuals surviving to reproduce in the soils with highest clay contents. This appears to be one of the most important findings that certainly has a major bearing on the range of adaptation of the weed. Seed mass declined whereas seed production increased in relatively coarser soils with the exception of nearly pure sand. In soils rich in clay, plants produced a smaller number of larger seeds. These data suggest that variation in fundamental functional traits would enable P. hysterophorus to adjust to a variety of habitat conditions. 相似文献
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Summary The objective of this study was to find measurable characters to aid the plant breeder in predicting both rubber percentage and rubber yield of guayule (Parthenium argentatum Gray). A field of 234 guayule breeding lines was harvested by clipping in February 1986. Forty-two of these lines were selected for further evaluation on the basis of superior regrowth, rubber content and yield. These 42 lines were reharvested in February 1987. Nineteen variables were evaluated including percent rubber and resin, rubber and resin yield (g/plant), plant height (cm), width (cm), and volume (m3), fresh and dry weight (kg/plant), percent dry weight, stem number, mean stem diameter (cm), total and mean stem circumference (cm), total and mean stem area (cm2), total stem circumference/total stem area (cm-1), and regeneration at two dates. Dry weight (kg/plant) had the best correlation to rubber yield (r=0.85), and plant volume best predicted dry weight (r=0.83). These variables did not correlate as highly with percent rubber. The best statistical regression model for percent rubber included four variables, fresh and dry weight, percent dry weight, and plant volume. This model accounted for 51% of the variation. In comparison, the best regression of rubber yield had an R2=0.85 for plant height and width, volume, and dry weight. 相似文献
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[目的]研究银胶菊不同部位水浸液对蔬菜种子和幼苗的化感作用。[方法]以上海青和油麦2种蔬菜作物为受体,通过室内培养法,研究银胶菊不同部位水浸液对上海青和油麦种子萌发和幼苗生长的影响。[结果]银胶菊不同部位水浸液对上海青和油麦种子的萌发具有不同程度的抑制作用,且抑制作用大部分随处理浓度的增加而增强;对幼苗根长均具有抑制作用,而对苗高均表现出促进作用;对2种植物幼苗的鲜重也有一定的化感效应,有的表现为促进作用,有的表现为抑制作用。[结论]研究结果为银胶菊对植物的化感作用机理研究、银胶菊抑制植物生长的化感物质分离研究奠定了基础。 相似文献
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银胶菊的花对小麦的化感作用机制 总被引：1，自引：0，他引：1
采用温室盆栽法,研究了银胶菊的花水浸提液对小麦生长及其生理生化机制的影响,以明确其对小麦的化感作用。结果显示,花水浸提液抑制小麦种子萌发和幼苗生长,且抑制强度随浸提液浓度的升高而加强;随着花水浸提液浓度的增加,小麦叶片光合作用、光合色素含量和过氧化氢酶(CAT)活性下降,磷(P)和丙二醛(MDA)含量升高,氮(N)含量呈现先降低后趋于正常的变化趋势,硝酸还原酶(NR)活性呈现先降低后升高的变化趋势,谷氨酰胺合成酶(GS)活性没有显著变化,而过氧化物酶(POD)和超氧化物歧化酶(SOD)活性则呈现先升高后降低的变化趋势。表明银胶菊的花水浸提液抑制小麦叶片光合作用,提高了小麦叶片的MDA含量,并降低了小麦叶片SOD、POD和CAT的活性。 相似文献
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Two sets of field experiments were conducted at two sites (lowland and intermediate altitude) for 2 years in eastern Ethiopia to determine the influence of parthenium weed ( Parthenium hysterophorus ) density and duration of competition on grain yield of sorghum. In the first set of experiments, target weed densities of 0, 3, 7, 13, 27, 53 and 100 plants m -2 were used. Yield loss was severely affected by parthenium weed density, peaking at 97% at the lowland site in 2000. At this site, even very low density (e.g. three plants m -2 ) resulted in a high yield loss (69%). Owing to differences between sites and years, however, it was not possible to specify meaningfully the threshold densities for weeding. In the critical weed-free period experiments, four parthenium weed-infested and four weed-free periods from emergence to harvesting of sorghum were maintained by hand hoeing. The critical periods for weed control, i.e. the period over which weeding had the greatest benefit on yield, were 19 - 69 and 40 - 57 days from emergence of sorghum in 1999 and 2000, respectively, at the intermediate altitude (assuming an acceptable loss of 10%). In the lowland, however, it ranged directly from emergence to 61 and 66 days, indicating more severe competition at this site. The substantial variation in yield and yield loss between sites and years illustrates the problems of attempting to give well-established, accurate recommendations for threshold densities and critical periods in small-scale, rain-fed agriculture. 相似文献
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Performance of improved guayule lines in Australia 总被引：1，自引：0，他引：1
Guayule (Parthenium argentatum Gray) is a potential source of commercial natural rubber. Its commercialisation depends mainly on economical plant production. The objective of this study was to evaluate the performance of improved lines in Australia. Seeds from five improved lines (AZ-1, AZ-2, AZ-3, AZ-5 and AZ-6) and two previously developed guayule lines (N 565 and 11591) were obtained from the Agricultural Research Service (ARS) of the United States Department of Agriculture (USDA). Seedlings from these lines were grown in a glasshouse for 3 months and later transplanted in a field experiment in early September 2001. Plant height and width were monitored from transplanting to 62 weeks at regular intervals. After 62 weeks, plant dry matter production, rubber and resin content, and yields were analysed. Plant height and width of the improved lines were higher than N 565 and 11591. Plant dry matter, rubber and resin yields were significantly different among lines. Of the five lines, AZ-1 and AZ-2 produced rubber yields of 620 and 550 kg/ha, respectively and these yields were significantly greater than for N 565 (371 kg/ha) and 11591 (391 kg/ha). AZ-1 and AZ-2 also produced significantly higher resin yields, 727 and 668 kg/ha, respectively, than those for N 565 (436 kg/ha) and 11591 (325 kg/ha). Rubber and resin yield increase of lines, AZ-1 and AZ-2, were in the range of 41–68% and 53–123%, respectively over N 565 and 11591. AZ-1 tended to produce higher rubber and resin yields than AZ-2 but exhibited highly variable plant height (CV=25%) and width (CV=41%) indicating potential for further genetic improvement. AZ-2 offers the best combination of desirable characters including early vigour, uniformity and comparatively higher rubber and resin yields. 相似文献
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银胶菊不同组织部位对黄瓜化感作用初步研究 总被引：1，自引：0，他引：1
运用室内培养皿生物测定法,对银胶菊化感作用研究,发现茎、叶、花水浸提液对黄瓜根长、芽长有抑制作用,抑制强度随处理浓度的增大而加强,在浓度为200 g/L时,叶、花水浸提液的根长抑制率和芽长抑制率均达到100.0%,芽长抑制强度随根水浸提液处理浓度的增大而减弱。根、茎、叶、花水浸提液能降低黄瓜的根系活力,提高丙二醛含量,表明不同组织部位水浸提液对黄瓜造成了伤害。 相似文献
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外来入侵植物银胶菊不同部位的化感作用 总被引：1，自引：0，他引：1
在室内以滤纸为载体用离体生物测定方法测定了银胶菊（Parthenium hysterophorus）根、茎、叶和果实水浸提液对蔬菜萝卜(Raphanus sativus)和杂草马唐(Digitaria sanguinalis)、苘麻(Abutilon theophrasti)种子的化感效应,同时在温室内以土壤为载体测定了银胶菊不同部位干粉对这3种植物种子萌发和幼苗生长的影响。室内生测试验结果表明,银胶菊叶和果实水浸提物对3种受体植物种子的萌发和幼苗生长均有较强的抑制作用,其中受体萝卜和苘麻的敏感性较高,而马唐的敏感性较低。温室盆栽试验也表明,银胶菊叶和果实对受体生长的影响明显高于根和茎,说明叶和果实是集中表现银胶菊化感作用的特定部位。 相似文献
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HARMINDER PAL SINGH DAIZY RANI BATISH JASVIR KAUR PANDHER RAVINDER KUMAR KOHLI 《Weed Biology and Management》2005,5(3):105-109
A study was conducted to assess the phytotoxicity of residues of Parthenium hysterophorus , an exotic invasive weed, towards the growth of three Brassica species ( Brassica campestris, Brassica oleracea and Brassica rapa ). The early growth of crops, measured in terms of seedling length and dry weight, was significantly reduced when grown in soil amended with varying amounts of Parthenium residues. A direct relationship was observed between the amount of residue incorporated in the soil and growth reduction. This adverse effect on Brassica crops indicates the presence of some growth-retardatory substances which are possibly released by the residues into the soil medium. In order to test this, aqueous extracts (1, 2, and 4%) of residues were prepared. It was observed that, in a laboratory bioassay, these extracts severely reduced the early growth of Brassica species, thereby indicating the presence of some water-soluble, inhibitory principles in Parthenium residues. A significant amount of the phenolics, the largest group of secondary metabolites usually implicated in allelopathy, was estimated in residue extracts, as well as in residue-incorporated soil. The phenolic content increased with increasing residue concentration, thereby showing their direct involvement in the observed growth inhibitions. Therefore, the study establishes that Parthenium residues exert an allelopathic influence on the early growth of Brassica crops by releasing water-soluble phenolics into the soil. 相似文献