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Biswas DK Xu H Li YG Liu MZ Chen YH Sun JZ Jiang GM 《Journal of experimental botany》2008,59(4):951-963
Modern wheat (Triticum aestivum L.) is one of the most ozone(O3)-sensitive crops. However, little is known about its geneticbackground of O3 sensitivity, which is fundamental for breedingO3-resistant cultivars. Wild and cultivated species of winterwheat including donors of the A, B and D genomes of T. aestivumwere exposed to 100 ppb O3 or charcoal-filtered air in opentop chambers for 21 d. Responses to O3 were assessed by visibleO3 injury, gas exchange, chlorophyll fluorescence, relativegrowth rate, and biomass accumulation. Ozone significantly decreasedlight-saturated net photosynthetic rate (–37%) and instantaneoustranspiration efficiency (–42%), but increased stomatalconductance (+11%) and intercellular CO2 concentration (+11%).Elevated O3 depressed ground fluorescence (–8%), maximumfluorescence (–26%), variable fluorescence (–31%),and maximum photochemical efficiency (–7%). Ozone alsodecreased relative growth rate and the allometric coefficient,which finally reduced total biomass accumulation (–54%),but to a greater extent in roots (–77%) than in the shoot(–44%). Winter wheat exhibited significant interspeciesvariation in the impacts of elevated O3 on photosynthesis andgrowth. Primitive cultivated wheat demonstrated the highestrelative O3 tolerance followed by modern wheat and wild wheatshowed the lowest. Among the genome donors of modern wheat,Aegilops tauschii (DD) behaved as the most O3-sensitive followedby T. monococcum (AA) and Triticum turgidum ssp. durum (AABB)appeared to be the most O3-tolerant. It was concluded that thehigher O3 sensitivity of modern wheat was attributed to theincreased O3 sensitivity of Aegilops tauschii (DD), but notto Triticum turgidum ssp. durum (AABB) during speciation. Key words: Biomass, Chl a fluorescence, genome, ozone sensitivity, relative growth rate, stomatal conductance, winter wheat
Received 20 September 2007; Revised 30 November 2007 Accepted 16 January 2008 相似文献
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Gurpreet Kaur Hunjan 《Acta Physiologiae Plantarum》2006,28(3):205-215
In the present study α-amylase was partially purified from detached grains of five day old seedlings of two wheat (Triticum aestivum L.) varieties, showing differential responses to high temperature stress at seedling stage. A three step purification via
ammonium sulphate precipitation, DEAE-cellulose column chromatography and gel filtration on Sephadex G-150 was employed. A
single α-amylase was detected in the high temperature sensitive PBW-175 variety, while two isozymes namely, α-amylase-1 and
α-amylase-2 were obtained in the relatively tolerant WL-711 variety. The pH optima of the three α-amylases were in 5.0–5.5
range and comparable to the cereal amylases. The temperature optima of PBW-175 α-amylase and α-amylase-1 of WL-711, which
appeared to be the major isozyme of the variety, were same at 45 °C and also comparable to cereal amylases. On the other hand
the optimum temperature for α-amylase-2 was high at 70 °C, which is unusual and not reported earlier for cereal amylases.
The Km of PBW-175 α-amylase was lower than the Km values of WL-711 isozymes, this was well co-related with an overall high
α-amylase activity detected in the detached grains of five day old seedlings of PBW-175 compared to WL-711. However WL-711
variety showed a better inherent seedling growth, vigour and EUE than PBW-175, may be because it had two α-amylase isozymes
which could compensate for the higher enzyme activity detected in PBW-175. Moreover, the presence of α-amylase-2 in the grain
of WL-711 having temperature optima of 70 °C, possibly rendered its seedlings tolerant to HS of 50 °C, while the seedlings
of PBW-175 succumbed to this temperature shock. 相似文献