Bryophytes of the northern Yukon Territory,Canada, collected by A. J. Sharp and others

Two hundred and eight taxa of bryophytes, including two hundred and seven species, are reported from extreme northern Yukon. Five hepatic and eighteen moss taxa represent new records for the Yukon, which areAnastrophyllum hellerianum (Nees) Schust.,Scapania degenii Schiffn. in K. Müll.,Riccardia palmata (Hedw.) Carruth.,Mannia sibirica (K. Müll.) Frye & Clark,Sauteria alpina (Nees) Nees,Sphagnum orientale Savich,Dicranum spadiceum Zett.,Anoectangium aestivum (Hedw.) Mitt.,Barbula coreensis (Card.) Saito,B. platyneura C. Müll. & Kindb.,Pottia obtusifolia C. Müll.,Splachnum vasculosum Hedw.,Bryum acutiforme Limpr. ex Hag.,B. bimum (Brid.) Turn.,B. intermedium (Brid.) Bland.,B. neodamense Itzigs.,Cinclidium latifolium Lindb.,Timmia comata Lindb. & Arn.,Orthothecium acuminatum Bryhn,Cratoneuron arcticum Steere,Drepanocladus brevifolius (Lindb.) Warnst.,D. intermedius (Lindb.) Warnst., andD. lycopodioides (Brid.) Warnst. Many of the other collections represent significant extensions of ranges to the arctic sector of the Yukon Territory.     

贵州省竹类植物分布新资料(I)

【目的】摸清贵州竹类资源本底,以补充和丰富贵州现有竹类资料,为后续竹产业的规划发展提供一定的依据。【方法】以“面”“点”结合的方式进行野外调查,标本的采集和鉴定,以及相关资料的查阅,整理出此前从未有分布记录的属和种。【结果】发现了贵州省竹类植物新纪录的1个属和6个种,即[/思]簩竹属（Schizostachyum）、[/思]簩竹（S. pseudolima McClure）、鸡窦簕竹（Bambusa funghomii McClure）、龙山玉山竹(Yushania longshanensis D. Z. Li & X. Y. Ye)、滑竹（Y. polytricha Hsueh et Yi）、少枝玉山竹（Y. pauciramificans Yi）和抱鸡竹（Y. punctulata Yi）,现予以报道。【结论】这些新纪录属和种在贵州的发现扩展了其分布范围,同时丰富了贵州竹类植物的多样性。     

Regulation of Succinate Dehyrogenase in Higher Plants: I. Some General Characteristics of the Membrane-bound Enzyme

The spectrophotometric phenazine methosulfate assay of succinate dehydrogenase was adapted to use with cauliflower (Brassica oleracea) and mung bean (Phaseolus aureus) mitochondria with suitable modifications to overcome the permeability barrier to the dye. Procedures in the literature for the isolation and sonic disruption of mitochondria from these sources were modified to assure maximal yield and stability of the enzyme. In tightly coupled mung bean mitochondria, as isolated, about half of the succinate dehydrogenase is in the deactivated state, and the enzyme is further extensively deactivated on sonication or freeze-thawing. In cauliflower mitochondria most of the enzyme is in the deactivated form, and little or no further deactivation occurs on sonication or freeze-thawing. Incubation of mitochondria from either source with succinate leads to full activation of the enzyme. The energy of activation for the conversion of the deactivated to the activated form in membranal preparations under the influence of substrate is about 30,000 cal/mole, essentially the same value as in animal tissues. Activation of the enzyme also occurs under the influence of a variety of other agents, among which the action of anions as activators is documented in the present paper. Activation is accompanied by the release of very tightly bound oxaloacetate. As in animal tissues, the enzyme appears to contain covalently bound flavin (histidyl 8α-FAD), and the turnover number is 19,400 moles of succinate oxidized/mole of histidyl flavin at pH 7.5, 38 C.