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A.?F.?Tjin?Wong?Joe R.?W.?Summers G.?D.?Lunn M.?D.?Atkinson P.?S.?KettlewellEmail author 《Euphytica》2005,143(3):265-269
In 1998 and 1999 the UK winter wheat variety Rialto produced unexpected low Hagberg falling numbers that could not be directly linked to sprouting. It was proposed that these reductions in quality could be due to pre-maturity α-amylase activity (PMAA). The problem was not identified during the selection and commercial development stages. Our study tested the hypothesis that the variety Rialto is PMAA-susceptible. Analysis was done on 13 year-location combinations of field grown Rialto. Together, visual and chemical assessments of sprouting and iso-electric focusing of α-amylase isozymes identified several samples with significant α-amylase activity in the apparent absence of sprouting. In addition, tests with α-amylase sensitive Phadebas gel revealed distinctive PMAA discoloration patterns in 10–44% of the grain from the 13 samples, leading to the conclusion that Rialto is PMAA-susceptible. Diurnal temperature range accumulated for an 11 day period during a warm spell in early simulated grain development displayed a significant but negative correlation with the number of grains showing clear PMAA discoloration patterns on Phadebas gel. The number of clear PMAA grains correlated positively with rainfall accumulated over 11 days. These results suggest that PMAA can increase under conditions similar to those conducive to pre-harvest sprouting. It is however also possible that in some instances both PMAA and incipient sprouting could have produced similar patterns of α-amylase activity. In addition to tests with Rialto, Phadebas gel tests were therefore also done with the known high Hagberg varieties Option and Malacca, sprouted in a controlled environment. Results from the additional gel tests suggest that visual and chemical assessments of sprouting in the grain combined with Phadebas gel analysis could identify PMAA more reliably in grain sub-samples than Phadebas gel analysis alone. 相似文献
23.
Dormancy of wheat grains, the property conferring sprouting resistance, is affected by environmental conditions experienced
during grain development. We investigated the hypothesis that short dormancy duration in U.K. wheat grain (thus a high risk
of post-maturity sprouting) is related to weather conditions, i.e. high temperatures during grain development. Four wheat
varieties were grown at four sites ranging from the far south to the far north of the country in the years 1995–1997,ensuring
different temperature and rainfall conditions during grain development. This paper focuses on one variety, Hornet, which has
a high sprouting resistance rating. Other varieties gave similar results. Serial laboratory germination tests (seven days,
20°C) at 100°C-dayintervals were used to measure dormancy duration, which was assessed from logistic curves fitted to the
data. During the experiment the mean temperatures during grain development differed by over4°C, due to the site × year effect.
Significant effects (p>0.05) of site and year (i.e. weather) on dormancy were found, when definitions of dormancy duration of DA (number of days from anthesis to 50% germination in seven days at 20°C) or DP (number of days from physiological maturity at 45% grain moisture to 50% germination) were used. Dormancy was markedly shorter
in the hot, dry year 1995 compared to the cooler, wetter years 1996 and 1997. A relationship, as postulated by Belderok, between
accumulated temperature during the dough stage of grain filling and dormancy duration was not found. However, a relationship
of dormancy duration to the mean temperature during grain development was found, with short dormancy periods occurring after
high mean temperatures were experienced.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
24.
Mrklas Ole Chu Angus Lunn Stuart Bentley Laurence R. 《Water, air, and soil pollution》2004,159(1):249-263
The release of alkanolamines and glycols into the subsurface soils poses a potential hazard to the environment through impacted soil and groundwater. This study investigated aerobic and anaerobic biodegradability of monoethanolamine (MEA), ethylene glycol (MEG) and triethylene glycol (TEG). Significant levels of MEA (31 000 mg/kg), MEG (500 mg/kg) and TEG (2100 mg/kg) were successfully aerobically biodegraded in bioreactors. The aerobic slurry experiments suggested initial phosphate (P) limitation, as biodegradation rates increased by one order of magnitude after phosphate addition. Anaerobic decay of MEA, MEG and TEG was unaffected by P-addition. MEA, MEG and TEG degradation products such as acetate, ethanol and ammonium at about 75 000 mg/kg, 8100 mg/kg and 8800 mg/kg degraded completely and did not prevent aerobic biodegradation. This study confirms proposed biodegradation pathways of MEA, MEG, TEG and their breakdown products in natural soil and groundwater using indigenous microbes. Levels of contamination studied here are significantly higher than previously reported. 相似文献
25.
The formyl cation, HCO+, has long been believed to be an important intermediate in the chemistry of carbon monoxide (CO) in acidic environments, but its spectroscopic observation in solution has been elusive. This species was generated by the reaction of CO with the liquid superacid hydrofluoric acid-antimony pentafluoride (HF-SbF5) under pressure and was observed by nuclear magnetic resonance and infrared spectroscopy. Equilibria between CO in the gas phase, CO dissolved in HF-SbF5, the SbF5 adduct of formyl fluoride, and HCO+ associated with several equilibrating anions of the type [SbxF5x+1]- are proposed to describe the system. 相似文献
26.
PC Sereno DB Dutheil M Iarochene HCE Larsson GH Lyon PM Magwene CA Sidor DJ Varricchio JA Wilson 《Science (New York, N.Y.)》1996,272(5264):986-991
Late Cretaceous (Cenomanian) fossils discovered in the Kem Kem region of Morocco include large predatory dinosaurs that inhabited Africa as it drifted into geographic isolation. One, represented by a skull approximately 1.6 meters in length, is an advanced allosauroid referable to the African genus Carcharodontosaurus. Another, represented by a partial skeleton with slender proportions, is a new basal coelurosaur closely resembling the Egyptian genus Bahariasaurus. Comparisons with Cretaceous theropods from other continents reveal a previously unrecognized global radiation of carcharodontosaurid predators. Substantial geographic differentiation of dinosaurian faunas in response to continental drift appears to have arisen abruptly at the beginning of the Late Cretaceous. 相似文献
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