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CLARE J. HOPKINS NOEL O. I. COGAN MELANIE HAND ERICA JEWELL JATINDER KAUR XI LI GERALDINE A. C. LIM ALISON E. LING CHRISTOPHER LOVE HAYLEY MOUNTFORD MARIJA TODOROVIC MEGAN VARDY GERMAN C. SPANGENBERG DAVID EDWARDS JACQUELINE BATLEY 《Molecular ecology resources》2007,7(4):697-700
The availability of expressed sequence data derived from gene discovery programs enables mining for simple sequence repeats (SSR), providing useful genetic markers for crop improvement. These markers are inexpensive, require minimal labour to produce and can frequently be associated with functionally annotated genes. This study presents the development and characterization of 16 expressed sequence tags (EST)‐SSR markers from Brassica juncea and their cross‐amplification across Brassica species. Sixteen primer pairs were assessed for polymorphism in all genomes of the diploid and amphidiploid Brassica species. The markers show reliable amplification, considerable polymorphism and high transferability across species, demonstrating the utility of EST‐SSRs for genetic analysis of brassicas. 相似文献
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JACQUELINE BATLEY CLARE J. HOPKINS NOEL O. I. COGAN MELANIE HAND ERICA JEWELL JATINDER KAUR SUKHJIWAN KAUR XI LI ALISON E. LING CHRISTOPHER LOVE HAYLEY MOUNTFORD MARIJA TODOROVIC MEGAN VARDY MARZENA WALKIEWICZ GERMAN C. SPANGENBERG DAVID EDWARDS 《Molecular ecology resources》2007,7(5):886-889
The availability of expressed sequence data derived from gene discovery programs enables mining for simple sequence repeats (SSR), providing useful genetic markers for crop improvement. These markers are inexpensive, require minimal labour to produce and can frequently be associated with functionally annotated genes. This study presents the development and characterization of 24 expressed sequence tags (EST)‐SSR markers from Brassica napus and their cross‐amplification across Brassica species. The markers show reliable amplification, genome specificity and considerable polymorphism, demonstrating the utility of EST‐SSRs for genetic analysis of wild Brassica populations and commercial Brassica germplasm. 相似文献
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Energetic Costs of Tissue Construction in Yellow-poplar and White Oak Trees Exposed to Long-term CO2Enrichment 总被引:2,自引:0,他引:2
Two methods were used to estimate construction costs for leaves,stems, branches and woody roots of yellow-poplar (LiriodendrontulipiferaL.) trees grown at ambient (35 Pa) and elevated (65Pa) CO2for 2.7 years and trees of white oak (Quercus albaL.)grown at these same CO2partial pressures for 4 years. Samplecombustion in a bomb calorimeter combined with measurementsof ash and nitrogen content provided the primary method of estimatingtissue construction costs (WG; g glucose g-1dry mass). Thesevalues were compared with a second, simpler method in whichcost estimates were derived from tissue ash, carbon and nitrogencontent (VG). Estimates of WGwere lower for leaves, branchesand roots of yellow-poplar and for leaves of white oak grownat elevated compared with ambient CO2partial pressures. TheseCO2-induced differences in WGranged from 3.7% in yellow-poplarroots to 2.1% in white oak leaves. Only in the case of yellow-poplarleaves, however, were differences in VGobserved between CO2treatments.Leaf VGwas 1.46 g glucose g-1dry mass in ambient-grown treescompared with 1.41 g glucose g-1dry mass for CO2-enriched trees.Although paired-estimates of WGand VGclustered about a 1:1 linefor leaves and branches, estimates of VGwere consistently lowerthan WGfor stems and roots. Construction costs per unit leafarea were 95 g glucose m-2for yellow-poplar trees grown at ambientCO2and 106 g glucose m-2for trees grown at elevated CO2partialpressures. No differences in area-based construction costs wereobserved for white oak. Whole-plant energy content was 1220g glucose per tree in ambient-grown white oak compared with2840 g glucose per tree for those grown at elevated CO2partialpressures. These differences were driven largely by CO2-inducedchanges in total biomass. We conclude that while constructioncosts were lower at elevated CO2partial pressures, the magnitudeof this response argues against an increased efficiency of carbonuse in the growth processes of trees exposed to CO2enrichment. Bomb calorimeter; construction costs; elevated CO2; energy allocation; global change; growth respiration; heat of combustion; respiration; Liriodendron tulipifera; Quercus alba 相似文献
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M. J. DURRANT B. J. G. LOVE A. B. MESSEM A. P. DRAYCOTT 《The Annals of applied biology》1973,74(3):387-394
Growth of the roots of sugar beet, potato and barley in the field was observed through glass panels and related to changes in soil moisture measured by a neutron probe during 1969–71. The depth of observed root growth was generally related to, but 10–15 cm deeper than, the maximum depth of soil-moisture extraction. On average of three years, sugar beet, potato and barley used water from the top 23, 33 and 45 cm soil respectively by the beginning of June, and from the top 70, 68 and > 100 cm soil by the end of June. Maximum soil drying in each horizon gave an in situ measure of available water capacity, and showed that sugar beet and barley eventually extracted similar amounts of water from each horizon, but potatoes extracted less, especially from below 60 cm. Between 30 and 100 cm deep, the in situ available water capacity (per 10 cm soil) progressively decreased from 16 to 10, 15 to 5 and 16 to 8 mm under sugar beet, potato and barley respectively. The calculated soil-moisture deficit (potential evapotranspiration minus rainfall) and measured soil moisture deficit were not related early in the growing period before the crops established much leaf cover. 相似文献
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Limited direct effects of a massive wildfire on its sagebrush steppe bee community 总被引:1,自引:0,他引:1
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1. Fire can affect bees directly through exposure to heat and smoke. Direct effects include mortality, injury, and displacement affecting at most two generations – adults and any immature progeny present during the fire. To study the direct effects of fire on bees, two criteria must be met. First, bees must be sampled soon after the fire event, before colonists arrive from outside the burn. Second, sampling locations must be far enough into the burned habitat to ensure that bees observed are survivors, and not foragers nesting outside the burn. 2. Bees were systematically sampled far inside (>7 km) and outside the burn perimeter immediately following a massive wildfire that burned primarily at night in sagebrush steppe habitat. Because adult females sleep in their nests, it was hypothesised that females of species with nests >10 cm underground would be safe from lethal heat, whereas females with shallow or above‐ground nests would be vulnerable. It was also hypothesised that fire would kill proportionately more males, as they typically sleep above ground. 3. Adult bees were present at all burned sample sites 14 and 21 days after the fire started. Many females were observed transporting pollen, indicative of active nest provisioning. Among the guild of bees surveyed at wild sunflowers (the only surviving flowering plant), fewer species were active within the burn. Guild composition was significantly altered, particularly by loss or depletion of several (but not all) sunflower specialists. Sex ratios did not shift, possibly due to surviving males aggregating in remaining patches of sunflowers. 相似文献