The dormancy release by KAR is associated with a reduction of coleorhiza and radicle sensitivity to ABA as well as with reduction the ABA/GA ratio in the coleorhiza, by a decrease content of ABA, and in the radicle, by a decrease the ABA and an increase of the GA contents. Both, karrikin 1 (KAR) and gibberellin A (GA), release dormancy in Avena fatua caryopses, resulting in the emergence of coleorhiza (CE) and radicle (RE). Moreover, KAR and GA stimulate CE and RE in the presence of abscisic acid (ABA), the stimulation being more effective in CE. The stimulatory effects of KAR and GA involve also the CE and RE rates. A similar effect was observed at KAR concentrations much lower than those of GA. KAR increased the levels of bioactive GA and GA in embryos and the levels of GA, GA, GA GA and GA in radicles. The stimulatory effect of KAR on germination, associated with increased levels of gibberellins (GA) and reduced levels of ABA in embryos, was counteracted by paclobutrazol (PAC), commonly regarded as a GA biosynthesis inhibitor. Consequently, KAR decreased the ABA/GA ratio, whereas PAC, used alone or in combination with KAR, increased it. The ABA/GA ratio was reduced by KAR in both coleorhiza and radicle, the effect being stronger in the latter. We present the first evidence that KAR-induced dormancy release requires a decreased ABA/GA ratio in coleorhiza and radicle. It is concluded that the dormancy-releasing effect of KAR in A. fatua caryopses includes (i) a reduction of the coleorhiza and radicle sensitivity to ABA, and (2) a reduction of the ABA/GA ratio (i) in the coleorhiza, by decreasing the ABA content, and (ii) in the radicle, by decreasing the ABA and increasing the content GA, particularly GA. The results may suggest different mechanisms of dormancy release by KAR in monocot and dicot seeds.
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http://dx.doi.org/10.1007/s00425-024-04387-1 | DOI Listing |
Front Plant Sci
October 2024
Shandong Academy of Forestry, Jinan, China.
Super absorbent polymers (SAP) provide moisture conditions that allow plant growth-promoting rhizobacteria (PGPR) to enter the soil for acclimatization and strain propagation. However, the effects of SAP co-applied with PGPR on the physiological characteristics of leaves and rhizosphere soil enzyme activities of poplar seedlings are not well understood. Here, a pot experiment using one-year-old poplar seedlings with five treatments, normal watering, drought stress (DR), drought stress + SAP (DR+SAP), drought stress + (DR +PGPR) and drought stress + SAP + (DR+S+P), was performed to analyze the contents of non-enzymatic antioxidants, osmotic regulators and hormones in leaves, as well as rhizosphere soil enzyme activities.
View Article and Find Full Text PDFFront Plant Sci
September 2024
Traditional Chinese Medicine (TCM) and Ethnomedicine Innovation and Development International Laboratory, Innovative Material Medical Research Institute, Hunan University of Chinese Medicine, Changsha, China.
BMC Plant Biol
September 2024
Department of Agriculture, Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, Tehran, Iran.
This research was conducted to investigate the efficacy of putrescine (PUT) treatment (0, 1, 2, and 4 mM) on improving morphophysiological and biochemical characteristics of Zinnia elegans "State Fair" flowers under salt stress (0, 50, and 100 mM NaCl). The experiment was designed in a factorial setting under completely randomized design with 4 replications. The results showed that by increasing the salt stress intensity, the stress index (SSI) increased while morphological traits such as plant height decreased.
View Article and Find Full Text PDFJ Plant Physiol
October 2024
Department of Plant Science, 222 Agriculture Building, University of Manitoba, Winnipeg, Manitoba, Canada, R3T 2N2. Electronic address:
Abscisic acid (ABA) and gibberellin (GA) are major regulators of seed dormancy, an adaptive trait closely associated with preharvest sprouting. This study examined transcriptional regulation of ABA and GA metabolism genes and modulation of ABA and GA levels in seeds of barley genotypes exhibiting a range of dormancy phenotype. We observed a very strong negative correlation between genetic variation in seed germination and embryonic ABA level (r = 0.
View Article and Find Full Text PDFPlanta
April 2024
Institute of Biology, University of Szczecin, Waska 13, 71-415, Szczecin, Poland.
The dormancy release by KAR is associated with a reduction of coleorhiza and radicle sensitivity to ABA as well as with reduction the ABA/GA ratio in the coleorhiza, by a decrease content of ABA, and in the radicle, by a decrease the ABA and an increase of the GA contents. Both, karrikin 1 (KAR) and gibberellin A (GA), release dormancy in Avena fatua caryopses, resulting in the emergence of coleorhiza (CE) and radicle (RE). Moreover, KAR and GA stimulate CE and RE in the presence of abscisic acid (ABA), the stimulation being more effective in CE.
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