Phytotoxic effects of Croton bonplandianum Baill. on weedy associates

Differential effects of several “litter” types on the germination of dry grassland species

“…Contrary to the relatively low variance in physical properties, significant differences were found in their effect on germination, much of which can be explained by chemical factors. Corresponding to our expectations and to results presented by Datta & Sinha-Roy (1975) and Bokhari (1978), GC-MS analysis of Stipa leaf extracts detected more phenolic compounds with known allelopathic effects in freshly dried than in senescent leaves. This may demonstrate that more allelopathic substances are produced in the first part of the vegetation period, while towards autumn plant synthesis could switch to storage, with the appearance of glycerine or arabinitol in autumn leaves of S. pulcherrima.…”

“…During decomposition, nutrient release from natural plant material can stimulate seedling growth (Schlatterer & Tisdale 1969), and we found increased germination of V. phoeniceum under the more rapidly decaying litter types, which amplifies differences in chemical properties of natural litters. These results emphasize possible differences between natural litter types, determined mainly by chemical differences attributable to the decay state (see also Datta & Sinha-Roy 1975;Bokhari 1978), thus the importance of the deliberate selection of ''litters'' used in the experiments.…”

“…In addition, chemical properties, i.e. the concentration of secondary metabolic compounds, may also differ between plant phenological and decay stages: plant material in early phenological stages may be more phytotoxic than senesced material, and fresh material may contain more allelopathic substances than partly decomposed material (Datta & Sinha-Roy 1975;Bokhari 1978). Therefore, we would expect that chemical effects are stronger in case of fresh compared to partly decomposed litter.…”

Effects of Atrazine and Phenolic Compounds on Germination and Seedling Growth of Some Crop Plants.

“…Many other workers have also reported the presence of phenolic compounds in soils (Blum, 1996;Kobayashi et al, 1996;Hrykun et al, 1996;Regnier and Macheix, 1996;Inderjit, 1996;Janovicek et al, 1997). The water soluble phenolic compounds are added to the soil as they are leached from plant parts of allelopathic species or are returned to the soil in the decomposition process of such plants (Guenzi and McCalla, 1966a,b;Datta and Sinha-Roy, 1975;Shaukat et al, 1983;Tongma et al, 1998). Einhellig (1987) reported that a combination of atrazine with ferulic acid (FA) was much more inhibitory than FA alone.…”

Effect of Systemic Fungicide (Topsin-M) and Insecticide (Dimecron) on Germination, Seedling Growth and Phenolic Content of Pennisetum Americanum L.

“…Increase in phenolic suffer from the chemical stress (Siddiqui, 1997) and phenolic content produced as a result of stress may act as protective compound against pathogenic fungi and insects (Friend, 1979). Compound especially phenolic compounds produced by chemical stress can inhibit germination and seedling growth (Heisey, 1990;Datta and Sinha-Roy, 1975;Friedman et al, 1977;Colton and Einhellig, 1980;Siddiqui and Ahmed, 1996). It has also been reported that phenolic compounds are responsible for limiting growth, respiration, photo-synthesis and disruption of cell membrane (Macias et al, 1992).…”