Growth and phenology of eight common weed species

Hegazy, Ahmad K.; Fahmy, Gamal M.; Ali, Md. Ibrahim; Gomaa, Nasr H.

doi:10.1016/j.jaridenv.2004.07.005

Cited by 24 publications

(20 citation statements)

References 30 publications

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“…Relative growth rate in leaf area (RGR LA , cm 2 cm -2 day -1 ), and in leaf dry mass (RGR DM , g g -1 day -1 ) were calculated, according to Hegazy et al (2005).…”

Section: Chlorophyll Contentmentioning

confidence: 99%

Leaf expansion in Rhamnus alaternus L. by leaf morphological, anatomical and physiological analysis

Varone

Gratani

2009

Trees

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Morphological, anatomical and physiological traits of Rhamnus alaternus during leaf expansion were analysed. Bud break occurred when mean air temperature was 14.1 ± 1.2C, and it was immediately followed by the increase of leaf area and leaf dry mass. The highest leaf expansion rates happened during the first 22 days of the process. Leaf area and leaf dry mass reached the steadystate value 46 and 62 days after bud break, respectively. Net photosynthesis increased from bud break to full leaf expansion, and total chlorophyll content had the same trend, confirmed by the correlation between the two variables. Leaf dark respiration peaked during the first 11 days of leaf expansion, then decreased and reached a steadystate value 34 days after bud break. R. alaternus completed cell division and cell enlargement of the epidermal tissue 28 days after bud break, and the ones of the mesophyll tissue at full leaf expansion. The results underline that morphological, anatomical and physiological leaf traits in R. alaternus are indicative of a less sclerophyllous species (i.e. higher specific leaf area) compared with other Mediterranean evergreen species. Moreover, the higher fraction of mesophyll volume occupied by the intercellular air spaces, and the ability to end the leaf expansion process before air temperature might be a limiting factor, makes R. alaternus closer to the mesophyte species

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“…Relative growth rate in leaf area (RGR LA , cm 2 cm -2 day -1 ), and in leaf dry mass (RGR DM , g g -1 day -1 ) were calculated, according to Hegazy et al (2005).…”

Section: Chlorophyll Contentmentioning

confidence: 99%

Leaf expansion in Rhamnus alaternus L. by leaf morphological, anatomical and physiological analysis

Varone

Gratani

2009

Trees

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“…It is characterized by a high relative growth rate (RGR) together with a high dry matter investment into leaves, during seedling and juvenile stages. This promotes the competitive ability of the species and may ensure a resource turnover from vegetative to reproductive structures later in the plant life cycle (Hegazy et al, 2005). E. colona begins to produce flower buds early in its lifespan, a behavior that ensures some seed production even in years with a short growing season (Hegazy et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…This promotes the competitive ability of the species and may ensure a resource turnover from vegetative to reproductive structures later in the plant life cycle (Hegazy et al, 2005). E. colona begins to produce flower buds early in its lifespan, a behavior that ensures some seed production even in years with a short growing season (Hegazy et al, 2005). Though E. colona is one of the most serious grass weeds, its phytotoxic potential has received little attention.…”

Section: Introductionmentioning

confidence: 99%

Phytotoxic effects of Echinochloa colona (L.) Link. (Poaceae) extracts on the germination and seedling growth of weeds

Gomaa

AbdElgawad

2012

Span. j. agric. res.

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This paper aims to study the phytotoxic potential of Echinochloa colona in order to explore its potential as bioherbicide. In this way, the phytotoxic effects of the most active fraction and pure compound from methanol (MeOH) extract of E. colona shoots on germination and seedling growth of ten weed species and on E. colona itself were evaluated. A lettuce seed bioassay indicated that dichloromethane (CH 2 Cl 2 ) soluble fraction of MeOH extract had the most phytotoxic activity. The most phytotoxic active compound of CH 2 Cl 2 fraction was isolated and identified as tricin. ) significantly stimulated germination and seedling growth of some test species. There was no significant effect of the low concentration of tricin (50 µmol L -1 ) on germination and elongation of roots and shoots of species. Higher concentrations of CH 2 Cl 2 fraction (500, 1000 mg L -1 ) and tricin (100, 200 µmol L -1 ) inhibited germination and seedling growth of most species. The results suggest that CH 2 Cl 2 fraction and tricin might be potentially useful as bioherbicide for weed control in agriculture.Additional key words: allelochemicals; bioherbicide; tricin; weed control. ResumenEfectos fitotóxicos de extractos de Echinochloa colona (L.) Link. (Poaceae) sobre la germinación y el crecimiento de plántulas de malas hierbasEn este trabajo se estudia el efecto fitotóxico de la planta Echinochloa colona para explorar su potencial como herbicida natural. Se evaluaron los efectos fitotóxicos de la fracción más activa y del compuesto más puro del extracto de metanol de tallos de E. colona sobre la germinación de semillas y el crecimiento de plántulas de diez malas hierbas incluyendo E. colona. El ensayo biológico en semillas de lechuga indicó que la fracción soluble del diclorometano (CH 2 Cl 2 ) mostró la actividad fitotóxica más importante. Se aisló e identificó el componente activo más fitotóxico del CH 2 Cl 2 , que fue la tricina. La fitotoxicidad de estos compuestos se analizó con tres concentraciones distintas de CH 2 Cl 2 (100, 500 y 1000 mg L -1 ) y tres de tricina (50, 100, 200 µmol L -1 ) sobre la germinación de semillas y el crecimiento de plántulas de las especies Portulaca oleracea, Corchorus olitorius, Brachiaria reptans, Euphorbia heterophylla, Dinebra retroflexa, Hibiscus trionum, Amaranthus graecizans, Amaranthus hybridus, Convolvulus arvensis, Setaria pumila, y también E. colona. La concentración 100 mg L -1 de CH 2 Cl 2 estimuló significativamente la germinación de semillas y el crecimiento de plántulas de algunas de las especies de estudio. No hubo ningún efecto significativo de la concentración 50 µmol L -1 de tricina sobre la germinación de semillas o la elongación de raíces y tallos de las especies. Concentraciones más altas de CH 2 Cl 2 (500, 1000 mg L -1 ) y tricina (100, 200 µmol L -1 ) inhibieron la germinación de semillas y el crecimiento de plántulas de la mayoría de las especies. Los resultados sugieren que la fracción soluble del CH 2 Cl 2 y la tricina podrían ser potencialmente empleadas como herbicida...

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“…Hegazy et al (2004) attributed its dominance in clover fields to its discoid stem that enables this species to survive even after several cuttings of the crop. Euphorbia helioscopia is a dominant species in group F, and is one of the common species in groups B and C. Hegazy et al (2005) showed that Euphorbia helioscopia produces its flower buds early in its lifespan and continuously grows, and produces flowers, fruits and seeds. Production of flower buds starts early in the growing season to ensure some seed production even if the growing season is cut.…”

Section: Discussionmentioning

confidence: 99%

Floristic diversity and vegetation analysis of <i>Brassica nigra</i> (L.) Koch communities

Gomaa¹,

Sherif²,

Hegazy³

et al. 2012

Egypt. J. Bio.

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The floristic composition and species diversity of Brassica nigra communities were investigated in Beni Suef Governorate, Egypt. In 46 stands, a total of 49 species belonging to 42 genera and 18 families were recorded. Vegetation classification and ordination distinguished seven groups: two in reclaimed land only, three groups in old cultivated land only, and two that occurred in both types of land. The species that dominated these groups were Brassica nigra, Sonchus oleraceus, Beta vulgaris, Cichorium endivia, Euphorbia helioscopia and Anagallis arvensis. The highest species diversity was mainly in groups from reclaimed land, and in wheat compared to other crops. Edaphic factors, especially soil texture, CaCO 3 and organic carbon, contributed significantly to explaining the distribution of some weed species, but not with that of B. nigra. The allelopathic potential of Brassica nigra reported in previous studies did not seem to play a role in community composition.

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Growth and phenology of eight common weed species

Cited by 24 publications

References 30 publications

Leaf expansion in Rhamnus alaternus L. by leaf morphological, anatomical and physiological analysis

Leaf expansion in Rhamnus alaternus L. by leaf morphological, anatomical and physiological analysis

Phytotoxic effects of Echinochloa colona (L.) Link. (Poaceae) extracts on the germination and seedling growth of weeds

Floristic diversity and vegetation analysis of <i>Brassica nigra</i> (L.) Koch communities

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