Sweet corn (Zea mays L.) varieties carrying the sh2 gene are in high demand, but such varieties have poor stress tolerance, especially during plant establishment. Trichoderma harzianum Rifai strain 1295-22 is a biocontrol fungus developed to provide season-long colonization of crop roots. It has the potential to reduce root rot and increase root growth. In the absence of detectable disease, colonization by Trichoderma increased root and shoot growth by an average of 66%. The enhancement was not uniform among the plants. Low- and intermediate-vigor plants were larger in the presence of Trichoderma, but high-vigor plants were not further enhanced by the fungus. Seeds that were subjected to oxidative stress with 0.05% NaOCI had much-reduced vigor; subsequent treatment with Trichoderma fully restored vigor. This result indicates that the damage caused by hypochlorite is specifically repaired by Trichoderma. Treatment of imbibed but unemerged seeds with cold (5/10 °C night/day) for varying periods reduced subsequent growth. Plants with Trichoderma-colonized roots were 70% larger at all durations of cold treatment. The absence of interation indicates the growth reduction due to cold and the growth enhancement due to Trichoderma are by different mechanisms. Allelopathic reduction in root growth by rye was mimicked by applying benzoxazolinone to the soil. Trichoderma-colonized roots grew faster, but the characteristic shortening of the radicle still occurred. There was no interaction between Trichoderma and allelopathy, indicating that these two treatments affect growth by independent mechanisms. The different ways that growth was enhanced by Trichoderma lead us to propose that this fungus acts, in part, by reversing injurious oxidation of lipids and membrane proteins. Root growth is markedly enhanced by colonization with Trichoderma harzianum. This enhancement can restore some stress-induced growth reduction and may directly reverse oxidative injury.
Peters, H.C. Luu, K.T. 1985 Allelopathy in tall fescue 273 283 Thompson A.C. Chemistry of allelopathy: biochemical interactions among plants ACS Washington, D.C Smith, M.W. 1991 Pecan
growth observed with cypress mulch, but the potential role of allelopathy warrants further investigation. Literature Cited Abouziena, H.F. Hafez, O.M. El-Metwally, I.M. Sharma, S.D. Singh, M
growth in soils with a history of litter from recently killed C. micronesica trees. We used standard allelopathy-based research protocols using activated charcoal as a substance that adsorbs organic compounds in combination with fertilization to correct
, 2003 ). After incorporation into soil, cover crop residues may suppress weeds by inhibiting weed emergence and growth through allelopathy ( Kumar et al., 2008b ; Weston, 1996 ), immobilizing nitrogen ( Dyck and Liebman, 1994 ; Kumar et al., 2008a
many studies, including our own, have shown inconsistent control ( Bertin and Weston, 2004 ). Over the last decade, the study of plant-plant interactions and the use of allelopathy and plant interference as a potential weed management tool has received
seedling growth of various crops. Despite this progress, several aspects of allelopathy by sunn hemp are not well understood. Sunn hemp has considerable genetic diversity ( Wang et al., 2006 ), but possible differences in allelopathic potential of different
Allelopathy has traditionally been defined as the inhibitory effect of compounds released by one plant on another plant. A broader but less accepted definition of the term includes effects of plants on microorganisms that are mediated by
-inhibitory activity of asparagus at the laboratory level ( Motoki et al., 2006a ). Motoki et al. (2002) examined the effect of the flowable agent in activated C (herein referred to as “activated C F”) to mitigate allelopathy in asparagus. The results of tests on
( Alysicarpus vaginalis ) (74%) and hairy indigo ( Indigofera hirsuta ) (64%) cover crops ( Linares et al., 2008 ). Thus, the sunn hemp allelopathy carryover should be considered when selecting it as a cover crop. Sorghum-sudangrass ( Sorghum ×drummondi ) is a