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Early Seedling Growth (early + seedling_growth)
Selected AbstractsChemical Characterization of New Oxylipins from Cestrum parqui, and Their Effects on Seed Germination and Early Seedling GrowthCHEMISTRY & BIODIVERSITY, Issue 9 2008Antonio Fiorentino Abstract Isolation, chemical characterization, and phytotoxicity of five new oxylipins, together with seven already known related compounds, from Cestrum parqui L',Hérl. is reported. All the structures were elucidated on the basis of their spectral data, especially 1D- (1H- and 13C-NMR, DEPT) and 2D-NMR (COSY, TOCSY, HSQC, HMBC, and NOESY). The configurations of the stereogenic C-atoms were determined by the Mosher's method. The compounds have been assayed for their phytotoxicity on Lactuca sativa at concentrations ranging between 10,4 and 10,8,M. The results of the phytotoxicity tests on the germination and growth of the test species, obtained by a cluster analysis, showed interesting relationship between the chemical structures of the compounds and their biological effects. [source] Comparative Effects of NaCl and Polyethylene Glycol on Germination, Emergence and Seedling Growth of CowpeaJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 4 2002B. Murillo-Amador Abstract Seeds of Paceño and Cuarenteño cultivars of cowpea (Vigna unguiculata L. Walp.) were tested for salt and drought tolerance at germination, seedling emergence and early seedling growth in NaCl and PEG-8000 solutions of different osmotic potentials (0, ,0.2, ,0.4, ,0.6, and ,0.8 MPa). Daily and final germination and emergence percentage, as well as germination and seedling emergence rate, and seedling growth were recorded under controlled conditions. Results showed that germination and emergence rate were delayed by both solutions in both cultivars, with differences between cultivars among growth stages, given that cultivar Cuarenteño, showed a higher germination rate than Paceño in NaCl, but Paceño was less affected by NaCl and PEG solutions at the emergence stage. Sodium chloride had a lesser effect on both cultivars in terms of germination rate, emergence rate and the final germination and emergence percentage than did PEG-8000. This conclusively proves that the adverse effect of PEG-8000 on germination, emergence and early seedling growth was due to the osmotic effect rather than the specific ion. Seedling growth was reduced by both stresses, but NaCl usually caused less damage than PEG to cowpea seedlings, suggesting that NaCl and PEG acted through different mechanisms. Zusammenfassung Vergleich der Wirkungen von NaCl und Polyethylenglykol auf die Keimung, das Auflaufen und das Sämlingswachstum von Kuhbohne Samen von Paceño- und Cuarenteño-Kultivaren von Kuhbohne (Vigna unguiculata L. Walp.) wurden hinsichtlich Salz- und Dürretoleranz zum Zeitpunkt der Keimung, des Sämlingsauflaufens und des frühen Sämlingswachstums in NaCl- und PEG-8000-Lösungen mit unterschiedlichem osmotischen Potential (0, ,0.2, ,0.4, ,0.6 und ,0.8 MPa) untersucht. Tägliche und abschließende Keimungs- und Auflaufprozente sowie Keimung und Sämlingsauflaufrate und Sämlingswachstum wurden unter kontrollierten Bedingungen bestimmt. Die Ergebnisse zeigen, dass die Keimung und die Auflaufrate durch beide Lösungen verzögert wurden bei beiden Kultivaren, wobei Unterschiede zwischen den Kultivaren hinsichtlich der Wachstumsstadien auftraten; der Kultivar Cuarenteño zeigte eine höhere Keimungsrate als Paceño in NaCl, während Paceño weniger beeinflusst wurde durch NaCl und PEG-Lösungen im Auflaufstadium. Natriumchlorid hatte einen geringeren Einfluss bei beiden Kultivaren hinsichtlich der Keimungsrate, der Auflaufrate und der abschließenden Keimungs- und Auflaufprozente als PEG-8000. Dies bestätigt, dass der ungünstige Einfluss von PEG-8000 auf die Keimung, das Auflaufen und das frühe Sämlingswachstum eine Folge des osmotischen Einflusses und nicht einer spezifischen Ionenwirkung ist. Sämlingswachstum war durch beide Behandlungen beeinträchtigt, aber NaCl zeigte meist eine geringere Schädigung als PEG bei Kuhbohnensämlingen; das lässt vermuten, dass NaCl und PEG durch unterschiedliche Mechanismen einwirken. [source] Influence of imidacloprid seed treatments on rice germination and early seedling growthPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 3 2008Mark M Stevens Abstract BACKGROUND: Seed treatments with the chloronicotinyl insecticide imidacloprid (Gaucho® 600 FS) were evaluated to determine whether differences in concentration and exposure regime influence the germination and early growth of rice. RESULTS: Continuous exposure to imidacloprid (4 days at 2000 mg AI L,1) significantly (P < 0.001) reduced normal germination by an average of 18% across the 15 cultivars examined. Nine days after sowing, plants showed no adverse effects from continuous imidacloprid treatment during germination, with shoot lengths and root system dry weights equalling, or occasionally exceeding (P < 0.05), those of untreated plants. Short-term imidacloprid exposure (2 h at 2000 mg L,1) at initial seed wetting did not affect germination (P > 0.05), and short-term (1 h) exposure of 48 h pregerminated seed to imidacloprid (2000 mg L,1) similarly had no significant effect on early subsequent growth. Plants arising from 48 h pregerminated seed exposed to imidacloprid (1 h) at concentrations up to 4000 mg L,1 immediately before sowing were not significantly different from control plants at either 9 or 25 days post-sowing. CONCLUSION: Results show that imidacloprid will have no adverse effects on plant growth if applied to pregerminated rice shortly before sowing. Continuous exposure of seed during germination had more pronounced effects, and the initial response of different cultivars was highly variable. Cultivars with high levels of sensitivity (such as IR72) require further testing before continuous exposure to imidacloprid during germination can be recommended. Copyright © 2007 Society of Chemical Industry [source] CYP707A3, a major ABA 8,-hydroxylase involved in dehydration and rehydration response in Arabidopsis thalianaTHE PLANT JOURNAL, Issue 2 2006Taishi Umezawa Summary Abscisic acid (ABA) catabolism is one of the determinants of endogenous ABA levels affecting numerous aspects of plant growth and abiotic stress responses. The major ABA catabolic pathway is triggered by ABA 8,-hydroxylation catalysed by the cytochrome P450 CYP707A family. Among four members of Arabidopsis CYP707As, the expression of CYP707A3 was most highly induced in response to both dehydration and subsequent rehydration. A T-DNA insertional cyp707a3-1 mutant contained higher ABA levels in turgid plants, which showed a reduced transpiration rate and hypersensitivity to exogenous ABA during early seedling growth. On dehydration, the cyp707a3-1 mutant accumulated a higher amount of stress-induced ABA than the wild type, an event that occurred relatively later and was coincident with slow drought induction of CYP707A3. The cyp707a3 mutant plants exhibited both exaggerated ABA-inducible gene expression and enhanced drought tolerance. Conversely, constitutive expression of CYP707A3 relieved growth retardation by ABA, increased transpiration, and a reduction of endogenous ABA in both turgid and dehydrated plants. Taken together, our results indicate that CYP707A3 plays an important role in determining threshold levels of ABA during dehydration and after rehydration. [source] | ||||||||||