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Potential allelopathic effect of Eucalyptus grandis across a range of plantation ages
Author(s) -
Zhang Danju,
Zhang Jian,
Yang Wanqin,
Wu Fuzhong
Publication year - 2010
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1007/s11284-009-0627-0
Subject(s) - allelopathy , rhizosphere , biology , germination , seedling , raphanus , eucalyptus , botany , agronomy , genetics , bacteria
Allelopathy of the eucalypt has been considered as an important mechanism for the biodiversity reduction in the eucalypt plantation. To understand the allelopathic potential of the eucalypt ( Eucalyptus grandis ) roots and rhizosphere soil along a chronosequence (2, 4, 6, 8, 10 years), the germination and growth characteristics of three plant species ( Raphanus sativus , Phaseolus aureus , and Lolium perenne ) growing nearby or beneath the eucalypt plantations were measured. The results showed that aqueous extract of E. grandis root suppressed the germination and early seedling growth of the target plants. The younger E. grandis exhibited a comparatively stronger allelopathic potential. The highest dose root extracts from 4 years old E. grandis showed the strongest inhibitory effects on the germination rates of the target species, the inhibitory rates were about 48, 51.2, and 56.56% for R. sativus , P. aureus , and L. perenne , respectively. However, present biotests of rhizosphere soils from 6, 8, and 10‐year‐old plantations exhibited a remarkable stimulative effect on L. perenne , which indicated that the soil might neutralize or dilute allelopathic agents with the increase of plantation age. In addition, according to GC–MS analysis, more allelopathic potential compounds were found in the rhizosphere soil and roots of younger E. grandis plantation. Moreover, more allelochemicals were obtained from soil than from roots. The allelopathic compounds in roots and rhizosphere soil may play important roles in allelopathy of E. grandis plantation. More attention should be paid to the younger E. grandis plantations for the relative higher allelopathic effects.