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31.
G. J. Scoles B. S. Gill Z. -Y. Xin B. C. Clarke C. L. McIntyre C. Chapman R. Appels 《Plant Systematics and Evolution》1988,160(1-2):105-122
The 5 S DNA units from 15 grasses in theTriticeae were analysed at the DNA sequence level. Four units carried duplications near the 3-end of the 5 S RNA gene with 3 of the duplications centred on the same base pairs as a duplication previously reported byGerlach & Dyer. The fourth duplication was located 3 downstream from the gene, in the spacer region. Apparent deletions were very frequent when units of the different grasses were compared and it was clear that these deletions did not extend into a 75 bp spacer region upstream from the 5 S RNA gene. This 75 bp region also tended to be more conserved between the grasses as compared to the high level of sequence change in the rest of the spacer region. — Phenetic relationships were established between the grasses using the sequence data. The relationships were generally consistent with the data from other parameters and, in addition, showed that two Australian grasses were closely related to the other Northern hemisphere genera examined. The data concerning the Australian grasses is discussed in relation to the isolated nature of Australia. 相似文献
32.
钙调蛋白(CaM)是一种多功能调节蛋白,它含有4个Ca~(2+)结合域.晶体研究表明所有Ca~(2+)都与主链氧原子及酸性残基侧链氧原子配位,但Ca~(2+)的配位层中是否有水分子存在尚未确定.木文利用核磁共振技术,以Mn~(2+)为探针,通过测定水质子的核磁弛豫速率T_(1P)_(-1)建立了有关Ca~(2+)配位层中水分子数目的模型,该模型指出Cam中高、低亲和位上Ca~(2+)结合水的能力不同,高亲和位上Ca~(2+)的配位层中没有水分子存在,而低亲和位上Ca~(2+)配位层中含两个水分子. 相似文献
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康定虫草主要寄主斜脉蝠蛾的研究 总被引:4,自引:0,他引:4
冬虫夏草是一味名贵的中药材.四川康定虫草的主要寄主斜脉蝠蛾翅面色斑多变异,可区分成“黑白斑”和“黄毛斑”两大色斑型.经交配试验和成虫形态特征(触角、口器、翅脉、前足、雌雄外生殖器和鳞片的超微结构等)的观察,证明为同一种,经鉴定是斜脉蝠蛾(Hepialus oblifurcus Chu et Wang)**. 相似文献
35.
高翔蜉属一新种:蜉蝣目:扁蜉蝣科 总被引:1,自引:1,他引:0
本文记述采自湖南省大庸市高翔蜉属一新种。该种以其阳茎叶外侧面具有一向前弯曲的钩状突起为显著特征,可区别于本属其他种类。 相似文献
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给完整的及切除肾上腺的雌性 Wistar 大鼠分別注射地塞米松、去氧皮质酮或地塞米松加去氧皮质酮;冷酚法提取心房总 RNA,用α-~(32P)标记的大鼠心房肽 cDNA 探针与之杂交。完整大鼠接受地塞米松和切除肾上腺后接受地塞米松加去氧皮质酮的大鼠,心房肽基因转录产物增加2倍,其余组无显著变化。结果提示糖皮质激素可促进心房肽基因表达,但此作用依赖于盐皮质激素的同时存在,单纯盐皮质激素不能增强该基因的表达。 相似文献
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Various daily photon doses (daily net number of photons perunit area), provided by varying both photon flux density andphotoperiod, were applied to dormant seed populations of fourgraminaceous species tested for germination in alternating-temperatureregimes on filter papers moistened with either water or a solutionof potassium nitrate. In all four species germination was dependentupon daily photon dose, the product of photon flux density andduration, and quantified by linear relations between the probitof percentage germination and the logarithm of the daily photondose determined by probit analysis. Photon flux density andphotoperiod only influenced germination indirectly as factorsof daily photon dose, except in Echinochloa turnerana (Domin)J.M. Black at high daily photon doses where lower germinationwas observed in continuous light than in 8 h d1 photoperiod.The low energy reaction, in which increasing dose promotes seedgermination, was observed in Echlnochloa turnerana and Eragrostistef(Zucc.) Trotter but not in the populations of Brachiariahumidicola (Rendle) Schwcickerdt and Panicum maximum Jacq. usedin this study. The high irradiance reaction, in which increasingthe photon dose reduces germination, was, however, observedin all four species. In Eragrostis tef potassium nitrate influencedthe response of seed germination to light, but in the remainingspecies its influence on this relationship was either additive(Panicum maximum) or nil (Brachiaria humidicola and Echinochloaturnerana) in the alternating-temperature regimes used in thisstudy. The implications of the quantal response to photon dosefor devising optimal light regimes to be applied in laboratorytests intended to maximize seed germination are discussed. Key words: Light, seed germination, seed dormancy, grasses 相似文献
40.