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Plant Weight (plant + weight)
Selected AbstractsIncreased effectiveness of the Trichoderma harzianum isolate T-78 against Fusarium wilt on melon plants under nursery conditionsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2009Agustina Bernal-Vicente Abstract BACKGROUND: The use of isolates of the genus Trichoderma to control Fusarium wilt in melon plants is one of the most recent and effective alternatives to chemical treatments. In this work we have studied the immobilization of the isolate Trichoderma harzianum T-78 on different carriers as an efficient method to control vascular Fusarium wilt of melon in nurseries. Different formulations were developed: liquids (spore suspension, guar gum and carboxymethylcellulose) and solids (bentonite, vermiculite and wheat bran). RESULTS: The introduction of F. oxysporum resulted in a significant decrease in seedling fresh weight. The treatments which gave a lesser reduction in weight and showing a greater biocontrol effect were the liquid conidial suspension and the solid treatments with bentonite and superficial vermiculite. Microbiological analyses revealed that the conidial suspension and all the solid treatments, except wheat bran, significantly decreased F. oxysporum populations. Of all the treatments assayed, bentonite produced the greatest decline in the F. oxysporum population. CONCLUSIONS: The most effective treatments against Fusarium wilt on melon plants were the solid treatments bentonite and superficial vermiculite. These two treatments gave the greatest plant weight, the lowest percentage of infected plants and the greatest T. harzianum population throughout the assay. Copyright © 2009 Society of Chemical Industry [source] Experiments on growth interactions between two invasive macrophyte speciesJOURNAL OF VEGETATION SCIENCE, Issue 1 2004Marie-Hélène Barrat-Segretain Tutin et al. (1980) Abstract. The success of invasive species has been attributed to the ability to displace other species by direct competition. We studied growth and possible competition between the two macrophyte species Elodea nuttallii and E. canadensis, because the former has been observed to replace the latter in the field. Additional experiments were conducted in aquaria with mixed plantings of Elodea species. Species growth was measured and competitive abilities of each species determined by applying the reciprocal yield model to mean plant weight and length. In monocultures the growth rates of the two species were similar, while in mixtures the growth rate of E. canadensis was significantly lower than that of E. nuttallii. E. canadensis was more sensitive to intraspecific than to interspecific neighbours, whereas E. nuttallii was indifferent to the presence of neighbours. Differential growth characteristics of Elodea species can explain the displacement of E. canadensis by E. nuttallii under eutrophic field conditions. [source] Heritability of morphophysiological traits and inbreeding effects in grazing-type lucernePLANT BREEDING, Issue 2 2005L. Pecetti Abstract To estimate heritability and inbreeding in grazing-type lucerne, 14 parent genotypes and their half-sib and selfed progeny were grown under spaced-plant conditions. Dry-matter weight (four cuts), plant height, basal plant diameter, stem density, and late-autumn vegetation were recorded on a plant basis. Genetic coefficients of variation for the three germplasm groups, and broad-sense heritability on a plot basis for parents were computed from variance component estimates; narrow-sense heritability was estimated from progeny-parent regression. Genetic variation was generally greater among selfed than half-sib progeny. Broad-sense heritability was high, while narrow-sense heritability was much lower for all traits except plant diameter. Inbreeding effects, assessed with comparison between parents and selfed progeny, were notable for plant weight and late-autumn vegetation only. The high correlation coefficients computed between parents and either progeny suggested the equivalent value of self- and polycross-progeny tests for selecting superior parents. [source] Experimental herbivory of native Australian macrophytes by the introduced Mozambique tilapia Oreochromis mossambicusAUSTRAL ECOLOGY, Issue 1 2010ROBERT G. DOUPÉ Abstract This study describes experimental herbivory and detritivory of three common native aquatic macrophyte species by the introduced Mozambique tilapia Oreochromis mossambicus (Peters) (Pisces: Cichlidae), and its physiological response to their consumption. There was a highly significant effect of fish herbivory on plant weight for each of the macrophyte species, but this effect was not influenced by any preference for periphyton. Despite the herbivory, there was a highly significant loss of fish body weight across all plant species and weight could only be maintained by supplementary feeding of a high protein fish flake. These results suggest that despite eating these plants, an alternative food resource may be needed for survival and may trigger trophic plasticity in O. mossambicus. [source] Lolium multiflorum density responses under ozone and herbicide stressAUSTRAL ECOLOGY, Issue 8 2009M. ALEJANDRA MARTÍNEZ-GHERSA Abstract Adaptations to overcrowding of individual plants result in density dependant control of growth and development. There is little information on how anthropogenic stresses modify these responses. We investigated whether combinations of diclofop-methyl herbicide and tropospheric ozone alter the pattern of expected growth compensation with density changes resulting from intraspecific competition in Lolium multiforum Lam (Poacea) plants. Individual plant vegetative parameters and total seed production were assessed for plants growing under various densities and different herbicide rates and ozone treatments. The stressors differently changed the frequency distribution for average individual plant weight resulting from increasing densities. Only herbicide affected seedling mortality. Plants were able to compensate during grain filling maintaining similar seed production , density relationships in all treatments. Our findings contribute to the understanding of the impact of stress factors on the demographic changes in plant populations. Important ecological implications arise: (i) contrasting responses to ozone and herbicide, alone and in combination of individual plants resulted in different biomass , density relationships; (ii) stress effects on plant populations could not be predicted from individual responses; and (iii) changes in competitive outcome by single or combined stress factors may alter the expected genotype frequency in a crowded population with few dominant individuals. [source] | ||||||||||