abstract most allelopathic studies have demonstrated the importance of live and dead plant tissues as source of allelochemicals. seeds of several species also have inhibitory effects on germination of the same or other species. in order to determine the allelopathic effects of common lambsquarters (chenopodium album) seeds, an experiment was conducted under controlled conditions in birjand univ...

It has been reported recently that coleoptiles of Zea mays develop a geotropic response under anaerobic conditions (2). The geotropic response of a coleoptile arises from the differential growth of the upper and lower halves of the organ. At least 3 independent investigations have shown that in Avena sativa coleoptiles growth is totally arrested in the absence of 02 (1,6, 9). It is therefore di...

It has been reported recently that coleoptiles of Zea mays develop a geotropic response under anaerobic conditions (2). The geotropic response of a coleoptile arises from the differential growth of the upper and lower halves of the organ. At least 3 independent investigations have shown that in Avena sativa coleoptiles growth is totally arrested in the absence of 02 (1,6, 9). It is therefore di...

Expansins are wall proteins that mediate a type of acid-induced extension in isolated plant cell walls (S. McQueen-Mason, D.M. Durachko, D.J. Cosgrove [1992] Plant Cell 4: 1425-1433). To assess the role of these proteins in the process of cell enlargement in living tissues, we compared the spatial and temporal growth patterns of oat (Avena sativa L.) coleoptiles with four wall properties relate...

The pH-dependence of acid-induced growth in excised segments of Avena sativa coleoptiles has been reinvestigated in the pH range 3 to 7. In contrast to previous reports (e.g. DL Rayle [1973] Planta 114: 63-73), only acidic buffers with a pH below 5.0 induce an extension response. A pH of 3.5 to 4.0 is required to mimic auxin-mediated growth. Very similar pH-response curves are obtained with bot...

In grass seedlings the network of cortical microtubules is reorganized during light-dependent growth of coleoptiles and mesocotyls. We investigated the effects of light-dependent growth on the relative steady-state levels of the mRNAs and protein levels of alpha-tubulin and the epsilon-subunit of the chaperonin containing tailless complex protein-1 in oat (Avena sativa) coleoptiles, which were ...

We isolated a mutant, named coleoptile phototropism1 (cpt1), from gamma-ray-mutagenized japonica-type rice (Oryza sativa). This mutant showed no coleoptile phototropism and severely reduced root phototropism after continuous stimulation. A map-based cloning strategy and transgenic complementation test were applied to demonstrate that a NPH3-like gene deleted in the mutant corresponds to CPT1. P...

Submergence induces rapid elongation of rice coleoptiles (Oryza sativa L.) and of deepwater rice internodes. This adaptive feature helps rice to grow out of the water and to survive flooding. Earlier, we found that the growth response of submerged deepwater rice plants is mediated by ethylene and gibberellin (GA). Ethylene promotes growth, at least in part, by increasing the responsiveness of t...

Coleoptiles of rice seeds that germinate under anoxia usually elongate to a length far exceeding the elongation that takes place under aerobic conditions. It has been suggested that expansins play a role in this process, but studies examining correlations between transcript levels of expansin genes and anoxic growth of rice coleoptiles are limited. In this study, we used real-time quantitative ...