Abstract
A greenhouse pot experiment was conducted to investigate the possible allelopathic effect of Eucalyptus rostrata leaf residue on some metabolic activities associated with growth of 10, 20 and 30 - day - old corn plants. The lower level of Eucalyptus treatment (0.5 %, w/w) induced stimulatory effect on the growth of shoot and root of corn plants. The positive effect was more obvious in shoot than in root growth. Inversely, high levels of incorporated Eucalyptus leaf residue (1 and 2 %, w/w) reduced all growth parameters of both shoot and root relative to the respective control, and this reduction was concentration dependent. The total phenolic aglycone content of mature Eucalyptus leaf was 16.89 mg g -1 dry weight present as water-soluble secondary metabolites. Qualitative and quantitative HPLC analysis of Eucalyptus rostrata leaves revealed the presence of nine phenolic compounds. The p-coumaric acid was the most dominant compound, while catechol and chlorogenic acid were detected in lesser amounts. A trace amount of salicylic acid, vanillin, coumarin, as well as caffeic, cinnamic and ferulic acids were also detected. The total phenolic content of corn shoot increased with the lower concentration of Eucalyptus residue and decreased with higher treatments. The lowest level of Eucalyptus residue (0.5%, w/w) increased the contents of photosynthetic pigments, particularly chlorophyll a content, which was correlated with increase in the total carbohydrate production. Similarly, the total nitrogen and total phosphorus, as well as nucleic acids were markedly higher than the control treatment. Negative pattern of changes in the contents of photosynthetic pigments, carbohydrate, nitrogen, phosphorus, phenolic compounds and nucleic acids, was observed in corn plant treated with high rates of Eucalyptus leaf residue (1 and 2%, w/w) as compared with their respective controls. These negative effects were concentration dependent.
Highlights
IntroductionEucalyptus (Family: Myrtaceae) includes about 150 species, seven of these species are cultivated in Egypt, most of them are trees of large size (Boulos and El-Hadidi, 1988)
Keywords Phenolic Compounds, Growth, Pigments and Eucalyptus (Family: Myrtaceae) includes about 150 species, seven of these species are cultivated in Egypt, most of them are trees of large size (Boulos and El-Hadidi, 1988)
Leaf extracts, decaying leaves and soil collected under Eucalyptus canopies inhibited seed germination and seedling growth of associated species (Suresh and Vinaya Rai, 1987; Konar and Kushari, 1995)
Summary
Eucalyptus (Family: Myrtaceae) includes about 150 species, seven of these species are cultivated in Egypt, most of them are trees of large size (Boulos and El-Hadidi, 1988). Allelochemicals are naturally released from intact living or dead Eucalyptus tissues and accumulate in soil rhizosphere in concentrations high enough to produce allelopathic effects. Lisanework and Michelsen (1993) demonstrated that aqueous leaf extracts of Eucalyptus trees significantly reduced both germination and radical growth of chickpea, maize and pea mostly at high concentrations. Corn (Zea mays L.) is one of the most important cereal crops growing in the Arab Republic of Egypt. It is used as a food for human consumption and as a feed grain for animals. Eucalyptus rostrata tree is used to study its allelopathic potential on some biochemical changes associated with the growth of corn (Zea mays L.)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
