不同覆盖方式对旱地马铃薯耗水特性和产量的影响

在陇中半干旱区设置玉米整秆带状覆盖(ST)、地膜覆盖(PT) 2种覆盖方式,以露地平作为对照(CK),研究了不同覆盖方式对马铃薯田土壤水分、耗水规律、产量及水分利用效率的影响。结果表明:与CK相比,覆盖处理显著(P0.05)提高了马铃薯播种至收获期0～200 cm土壤贮水量,ST和PT处理土壤贮水量较CK的增幅分别以收获期(12.3%)和淀粉积累期(9.1%)最大;覆盖处理降低了马铃薯全生育期耗水量,以ST处理的降幅最大(23.4%);与CK相比,ST处理显著降低了生育前期(播种-块茎形成期)和后期(淀粉积累期-收获期)的耗水量,显著增加了生育中期(块茎形成期-淀粉积累期)耗水量,并增加了深层土壤水分,而PT处理主要降低了生育前期和中期耗水,显著增加了生育后期耗水; ST和PT处理分别使马铃薯产量较CK显著增加32.4%和32.9%,水分利用效率提高73.8%和48.8%。综上可知,玉米整秆带状覆盖处理能显著改善马铃薯生育中后期0～200 cm土壤水分状况,使马铃薯关键生长阶段耗水增多,能显著提高马铃薯产量和水分利用效率。     

半干旱区旱地春小麦全膜覆土穴播对土壤水热效应及产量的影响

以春小麦"陇春27"为试材,研究半干旱区旱地全膜覆土穴播对土壤水热效应及小麦产量的影响。结果表明:与裸地平作(CK)相比,全膜覆土穴播(PM)和全沙覆盖平作(SM)增温效果呈"挂钩型",增温效果在小麦拔节期前最为明显,PM 0-25 cm土壤平均温度较CK提高1.8 ℃,全沙覆盖平作提高1.4 ℃,拔节后PM和SM的增温效果逐渐减弱直至消失,而在成熟期又呈现较弱的增温效果。PM和SM能提高小麦出苗后耗水速度并加大耗水量,其中,小麦拔节到扬花期耗水量增加最多,分别较CK平均增加54.93%和31.54%,且此阶段越是干旱,促进耗水作用越明显,PM促进作用大于SM。PM和SM能显著提高小麦阶段性水分利用效率(WUE_b),其中PM以苗期提高最多,2a平均较CK提高365.17%,SM拔节期提高最多,2年平均较CK提高119.00%。PM和SM在增温、促进耗水作用下使小麦各生育期提前并增加单株干重,产量较CK分别平均增加432.28%和375.82%, 水分利用效率(WUE)分别平均增加351.51%和338.29%,而且越干旱年份增产效应愈加明显。可见,PM和SM在越为干旱的年份促进耗水、增产和提高WUE的作用越显著,PM效果强于SM。     

秸秆带状覆盖对旱地冬小麦产量及土壤水热利用的调控效应

秸秆带状覆盖技术是一种利用玉米整秸秆进行局部覆盖种植的新型旱地覆盖栽培技术.为明确西北黄土高原典型旱作条件下秸秆带状覆盖对冬麦田土壤水热动态特征和产量的影响,在2013—2016年3个生长季,比较了秸秆带状覆盖(BSC)、免耕秸秆覆盖(NTS)、全膜覆土穴播(PFM)和露地种植(CK)下麦田土壤水温动态、小麦耗水特征、产量和水分利用效率的差异.结果表明: PFM显著增加了拔节前5～20 cm土壤温度,而BSC和NTS的增温效应主要在越冬期,但拔节后3种覆盖方式均具有显著的降温效应.BSC和PFM显著提高休闲期土壤蓄水效果,BSC显著改善全生育期0～200 cm土壤墒情,但PFM和NTS对生育期土壤墒情的改善主要集中在抽穗期以前,抽穗后PFM土壤墒情逐渐低于CK.BSC和PFM在保持周年耗水与CK无显著差异的基础上,显著提高生育期耗水量,增加拔节至开花期阶段耗水量,促进对120 cm以下土壤水分的利用.与CK相比,BSC、NTS和PFM显著增加单位面积穗数和成熟期生物量,籽粒产量分别显著增加19%～52%、14%～30%和15%～60%,周年水分利用效率分别显著提高19%～61%、14%～31%和15%～58%.BSC取得与PFM相近的产量和水分利用效率双增潜力.综合冬小麦产量、水温利用状况、周年耗水等因素,BSC是一种高产高效且利于西北旱作农业可持续发展的种植方式.     

西北半干旱区深旋松耕作对马铃薯水分利用和产量的影响

探明深旋松耕作技术(VRT)对西北黄土高原半干旱区马铃薯阶段性耗水、个体和群体生长状况、产量、水分利用效率和经济收益的影响,可为寻求抗旱增产、资源高效利用的耕作方法提供依据.本研究采用随机区组设计,于2016和2017年设置旋耕15 cm (TT)、深松40 cm (DLT)、深旋松耕40 cm (VRT) 3种耕作方式,测定马铃薯不同生育时期0～200 cm土层土壤贮水量、叶片SPAD值、叶面积指数、植株干物质量和产量等指标,计算阶段耗水量、水分利用效率(WUE)、商品率、商品产量、纯收益和新增收益等指标,探究深旋松耕作对马铃薯生产效率和经济效益的影响.结果表明: 与TT和DLT相比,VRT能显著促进马铃薯在盛花期和块茎膨大期的耗水,2016和2017年分别较DLT、TT增加了46.7、35.7和27.2、47.3 mm.由于VRT促进马铃薯耗水,叶片SPAD值、干物质量和叶面积指数均显著提高,证明它能促进马铃薯个体和群体发育.基于较高的个体和群体生长量,VRT的马铃薯块茎产量显著提高,分别在2016和2017年较DLT和TT增加了156.8%、47.8%和24.8%、41.0%,WUE相应地提高了92.3%、19.2%和18.9%、26.6%.深旋松耕作使马铃薯商品薯产量显著增加,纯收益和新增纯收益显著提高,在2016和2017年分别达到 12631.9、11019.1和29498.3、18245.5元·hm^-2.深旋松耕作促进马铃薯花期和块茎膨大期耗水,使马铃薯叶片SPAD值、干物质量和叶面积指数显著提高,导致块茎产量和水分利用效率明显升高,并提高了商品薯产量和纯收益,是适宜于西北黄土高原半干旱区马铃薯种植的耕作技术.     

西北黄土高原半干旱区全膜覆土穴播对土壤水热环境和小麦产量的影响

全膜覆土穴播是西北黄土高原旱作区大面积应用于密植作物栽培的关键增产技术,可显著提高降水利用率和作物生产力,但目前对其增产机制和环境效应缺乏系统研究分析。在2011—2013年以春小麦陇春27号为试验材料,设全膜覆土穴播(FMS)、地膜覆盖穴播(FM)和露地穴播(CK)3个处理,研究半干旱旱作区全膜覆土穴播的土壤水热效应及其对小麦产量的影响。结果表明,小麦苗期FMS在0—25 cm土层的平均地温比CK提高1.4—3.5℃,但孕穗到灌浆期正午地表地温比FM和CK分别降低5.3—6.4℃和3.1—4.3℃。FMS和FM使小麦拔节前0—200 cm土层土壤贮水量分别增加33.1和29.3 mm,且可促进小麦对深层水分(100—200 cm)的利用,FMS成熟期100—200 cm土层土壤贮水量比播前下降44.4—69.6 mm,较CK高8.4—145.5%,但FMS在休闲期补充土壤水分77—127 mm,分别较FM和CK增加4.5%—40.9%和12.8%—109.5%;FMS的休闲效率为30.5%—52.6%,比CK高12.8%—109.5%,比FM高4.5%—40.9%。基于对土壤水热环境和作物耗水的影响,FMS的产量达1750—3180 kg/hm2,水分利用效率为5.5—11.5 kg hm-2mm-1,分别比CK增加40%—220%和27%—239%,而且干旱年份的增加幅度更高。因此,FMS改善了小麦生长前期的土壤水热条件,调节作物不同生育期的耗水强度,显著提高作物水分利用效率和产量,并提高降水休闲效率,使小麦生育期耗散的土壤水分在休闲期得到有效补充。     

旱地全膜双垄沟播玉米的土壤水热效应及其对产量的影响

以春玉米品种沈单16号为试验材料,研究半干旱区（年均降雨量415 mm）旱地不同覆盖种植方式的土壤水热效应及其对玉米产量的影响.结果表明： 与裸地平作（CK）相比,全膜双垄沟播（PMF）、全沙覆盖平作（SM）在玉米抽雄前均能提高0～25 cm土层平均地温,其中PMF增温最高;随种植年限增加,各处理对土壤水分的耗散深度增加,种植第1年对20～120 cm土层的水分耗散最多,种植第2年对120～200 cm土层的水分耗散最多,其中PMF耗水量最高.PMF的穗粒数、穗粒重和百粒重最高,SM次之,CK最低;与SM和CK相比,2009和2010年PMF平均穗粒数分别增加13.5%和114.2%,平均穗粒重分别增加29.8%和321.1%,平均百粒重分别增加14.4%和95.4%;PMF和SM的产量分别比CK高333.1%和240.2%,水分利用效率（WUE）分别提高290.6%和227.6%.PMF玉米连续种植两年后,120～200 cm土层土壤水分消耗达72 mm,显著高于SM（45 mm）和CK(40 mm).由于PMF能提高苗期-抽雄期地温,促进作物前期生长,提高玉米对土壤水的利用,从而使穗粒数、百粒重等增加,表现出较高的产量和水分利用效率,但该模式对1 m以下土壤水分消耗较多,对保持水分年际平衡不利.     

全膜微垄沟穴播对春小麦土壤水热环境的影响及其光合和产量效应

减弱春季寒旱生境限制是提高甘肃中东部旱地春小麦产量的关键要素之一。本研究于2016—2018年在甘肃中部半干旱旱作区开展大田试验,以‘陇春35号’为供试品种,设置全膜微垄沟穴播(PRF)、全膜覆土穴播(PMS)和露地穴播(CK)3个处理,测定春小麦不同生育期0～300 cm土层的土壤含水量、0～25 cm土壤温度、叶片生物量、叶片叶绿素(SPAD)、光合速率、蒸腾速率和作物产量,从土壤水热-冠层发育-产量角度揭示PRF处理对土壤水热环境、水分利用效率(WUE)和产量的影响。结果表明: 与CK相比,PRF和PMS处理0～25 cm土层的土壤温度在苗期分别提高2.8和2.5 ℃,灌浆-成熟期分别降低1.4和0.9 ℃;0～300 cm土壤贮水量在播前-苗期分别增加59.7和41.8 mm;0～300 cm耗水量在苗期-灌浆期分别提高46.1和39.8 mm。与PMS处理相比,PRF处理的小麦苗期温度提高0.3 ℃,灌浆-成熟期降低0.5 ℃;播前-苗期0～300 cm土壤贮水量增加18.0 mm,拔节-成熟期耗水量提高13.0 mm。基于对土壤水热条件的优化,PRF和PMS处理的叶片生物量、SPAD值、苗期-灌浆期叶片净光合速率、蒸腾速率均显著高于CK,且PRF处理均显著高于PMS处理。PRF处理比PMS处理和CK分别增产9.1%和36.5%,WUE分别提高5.9%和30.8%。因此,PRF处理能提高苗期地温,降低灌浆-成熟期地温,促进春小麦苗期-灌浆期的耗水,提高了春小麦叶片SPAD值和生物量,增强春小麦苗期-灌浆期旗叶的光合功能,从而实现增产和水分高效利用,而且这一优势在欠水年份(2016和2017年)更加明显。     

半干旱雨养区不同覆膜方式对冬小麦土壤水分利用及产量的影响

在黄土高原半干旱雨养条件下,于2008—2009、2009—2010两个年度,以露地种植为对照(CK),研究了不同覆膜方式(全膜覆土穴播,全膜穴播,垄膜沟播)对旱地冬小麦产量和水分利用的影响。结果表明:两年度覆膜平均较CK产量分别显著提高49.4%和53.2%,水分利用效率提高11.8%和14.3%。覆膜的高产建立在高生长量、高耗水基础上,产量与生育期耗水量显著正相关(r=0.952*—0.958*),两年度覆膜分别平均较CK多耗水33.5%和34.1%。覆膜处理中以全膜穴播较CK的增产幅度和WUE提高幅度最大,耗水量也最大。由于覆膜耗水量大,覆膜各处理收获期0—200 cm土壤贮水量均显著低于CK,但通过全年连续覆膜和夏闲期降水补充,在下茬秋播时,覆膜各处理0—200 cm土壤贮水量均超过CK,夏闲期覆膜的水分休闲效率两年度分别平均高出CK 41.8和86.4个百分点,覆膜有利于土壤水分恢复和下茬作物的可持续生产。覆膜方式中,以全膜覆土穴播种植效益最高,两个年度纯收益平均达5531.6元/hm2,较CK增收2542.2元/hm2。综合考虑,全膜覆土穴播是一种高产高效兼顾、操作简单、适宜于半干旱雨养区推广应用的冬小麦覆膜种植方式。     

秸秆带状覆盖对半干旱雨养区冬小麦耗水特征和产量的影响

为探索半干旱雨养区小麦高产高效的覆盖种植技术新途径,于2013—2015年连续进行定位试验,设秸秆带状覆盖3行(覆盖带和种植带各30 cm,播种3行,SM₁)、秸秆带状覆盖4行(覆盖带和种植带各40 cm,播种4行,SM₂)、秸秆带状覆盖5行(覆盖带和种植带各50 cm,播种5行,SM₃)、全膜覆土穴播(PMF)、不覆盖露地(CK)5个处理,研究不同覆盖方式对西北雨养区冬小麦的耗水特性、产量和水分利用效率的影响.结果表明: 覆盖能显著改善作物土壤墒情,秸秆带状覆盖处理的土壤墒情好于地膜覆盖处理,且SM₁＞SM₂＞SM₃,0～2 m土壤贮水量在小麦开花期分别平均比CK高15.4%～20.8%、11.2%～14.7%和10.1%～14.5%;秸秆带状覆盖显著提高了生育期耗水量,降低了播种至开花阶段耗水量,增加了开花至成熟阶段耗水量及其占总耗水量的比例;覆盖会提高小麦对120 cm以下深层贮水的调用比例.与CK相比,秸秆带状覆盖和地膜覆盖处理籽粒产量分别显著增加11.9%～19.5%和26.9%～27.1%,水分利用效率分别显著提高9.8%～13.9%和18.4%～22.0%.因此,秸秆带状覆盖种植模式有利于降低冬小麦前期耗水比例,改善土壤墒情,显著提高冬小麦籽粒产量和水分利用效率,是适宜于西北黄土高原半干旱区冬小麦的绿色种植技术.     

施肥对旱地全膜覆盖垄沟种植马铃薯耗水特征及产量的影响

用化肥减量和分期施肥、增施有机肥来替代化肥是提高半干旱区全膜覆盖垄沟种植马铃薯水、肥利用效率的有效途径.在4年大田定位试验基础上,设置传统施肥(F)、化肥减量25%花期追施(DF)、化肥减量50%花期追施并增施有机肥(OF)3种养分管理模式,通过测定马铃薯不同生育期的土壤含水量和产量,计算阶段耗水量和水分利用效率,研究施肥方式对半干旱区马铃薯耗水过程的调控及其对产量和水分利用效率的影响.结果表明: 马铃薯花期的土壤贮水量DF最高,但处理间差异不显著;花后DF和OF的耗水深度较F有明显增加趋势.与F相比,2011—2014年DF花前耗水量显著下降,花后耗水量分别增加了36.2%、23.0%、24.8%和19.0%;OF未显著降低马铃薯花前耗水,但2011、2012年花后耗水量增加了20.7%和16.3%.DF的马铃薯块茎产量在2012—2014年较F平均增加2595.1 kg·hm^-2,水分利用效率(WUE)在2013、2014年分别显著增加14.4%和6.3%,达到显著差异;OF在2011—2014年平均马铃薯块茎产量较F增加了2945 kg·hm^-2,且WUE在2012—2014年显著高于F.DF和OF均能显著调节马铃薯花前花后耗水量,使马铃薯块茎产量、水分利用效率增加,但OF的增加幅度更大.     

白蚁与动物及微生物的共生类型及其机制

综述了白蚁螱客的主要种类、共生关系及相关机制的研究进展。白蚁螱客中,已报道的动物种类达170种。在与动物的共生关系中存在偏利共生（宾主共栖和异种共栖）、互利共生和无关共生三种;在与微生物的共生关系中,存在与内生菌（原生动物、细菌、真菌和放线菌）和外生菌（蚁巢伞菌等）间的互利关系。指出了白蚁与螱客研究中存在的问题,给出了解决方案,并提出了今后可能的研究热点或方向,为白蚁的综合利用（如纤维素酶）及今后研究物种间的协同进化提供了基础资料。     

New amino-dithiaphospholanes and phosphoramidodithioites and their rhodium and iridium complexes

New sulfur derivatives of phosphoramidite ligands were synthesized and the impact of the sulfur unit on the spectroscopic properties of their rhodium and iridium complexes was investigated. The new ligands Bn₂NPSCH₂CH₂S^a(P-S^a) (Bn = benzyl, 4), Bn₂NPSCHCHS^a(CH₂)₃C^aH₂(P-S^a)(C^a-S^a) (6) and Bn₂NP(4-XC₆H₄OMe)₂ (X = S, 7a; X = O, 7b) were converted to the rhodium and iridium complexes trans-[Rh(CO)Cl(L)₂] (L = 4, 6, 7), [RhCl(COD)(L)] (L = 4, 6, 7), [IrCl(COD)(7a)] and [IrCl₂Cp∗(6)]. For comparison, some phosphoramidite complexes of these formulations also were synthesized. The new metal complexes were spectroscopically analyzed. For the carbonyl complexes, the ν_CO IR stretching frequencies were lower than for the corresponding phosphite and phosphoramidite ligands. The ¹J_PRh coupling constants for the rhodium complexes with the new ligands were also smaller than for the respective phosphoramidite and phosphite complexes. Finally, the ¹J_PSe coupling constants of the selenides of the new ligands were lower than those of the phosphoramidite ligands but higher than for PPh₃. The spectroscopic data reveal that the new thio ligands 4, 6 and 7a are more electron donating than phosphites and phosphoramidites but less electron donating than PPh₃.     

Astrocytes and Synaptosomes Transport and Metabolize Lactate and Acetate Differently

Astrocytes transport the monocarboxylate acetate, but synaptosomes do not. The reason for this is unknown, because both preparations express monocarboxylate transporters (MCT). The transport and metabolism of lactate, another monocarboxylate, was examined in these two preparations, and the results were compared to those for acetate. Lactate transport is more rapid in astrocytes than in synaptosomes, but of lower affinity (Kms of 17 and 4 mM, respectively). Lactate (0.2 mM) is metabolized to CO2 more rapidly in synaptosomes than in astrocytes (rates of 0.37 and 0.07 nmol x mg protein(-1) x min(-1), respectively). The reason for this is unclear, but cellular differences in lactate dehydrogenase isotype expression may be involved. Acetate is metabolized to CO2 more rapidly in astrocytes than in synaptosomes (rates of 0.43 and 0.02 nmol x mg protein(-1) x min(-1), respectively). This is likely due to cellular differences in the expression of monocarboxylate transporter subtypes.     

Rapporteur report: Basics and technology and metrology and standards

The first and second sessions of the Workshop focussed on the basics of ultrasound and infrasound, their applications in both industry and medicine, and metrology and protection standards for ultrasound applications.     

Relative and combined effects of ethanol and protein deficiency on strontium and barium bone content and fecal and urinary excretion

To elucidate accumulation of minerals in human iliac arteries with aging, the content of minerals was analyzed by inductively coupled plasma atomic emission spectrometry. Bilateral common, internal, and external iliac arteries of 16 men and 8 women, ranging ages from 65 to 93 yr, were examined. It was found that an extremely high accumulation of calcium and phosphorus occurred in the common iliac artery at old age, being higher than that of the internal and external iliac arteries. It should be noted that the accumulation of calcium and phosphorus is the highest in the common iliac artery among the human arteries examined to date. Regarding sexual differences, the content of calcium and phosphorus in the common and internal iliac arteries was higher in women than in men, whereas their content in the external iliac artery was lower in women than in men.     

Cytoskeleton and mitochondrial morphology and function

It has been well established that the cytoskeleton is an essential modulator of cell morphology and motility, intracytoplasmic transport and mitosis, however cytoskeletal linkage to the organelles has not been unequivocally demonstrated. Indeed, cytoskeleton appears to be essential in determining and modulating gene phenotype as a function of cellular environment. According to recent studies, the organization of the cytoskeleton network together with associated protein(s) could be essential in regulating mitochondrial function and particularly the permeability of the mitochondrial outer membrane to ADP. The aim of this chapter is to summarize the main properties of the cytoskeletal environment of mitochondria and the possible role(s) of this network in mitochondrial function in myocytes.     

Cross-reactivity between storage and dust mites and between mites and shrimp

Many patients have sensitivities to multiple species of storage and house dust mites. It is not clear if this is because patients have multiple sensitivities to species-specific mite allergens or if these mites share many cross-reacting allergens. Our objective was to further define the cross-allergenicity between several species of storage and house dust mites using crossed-immunoelectrophoresis (CIE), crossed-radioimmunoelectrophoresis (CRIE), immunoblotting, and ELISA. CIE and CRIE reactions revealed that storage mites shared two cross-antigenic molecules and one of these bound IgE in a serum pool from mite allergic patients. Antibody in anti-sera built to each species of mite recognized many SDS–PAGE resolved proteins of other mite species and this suggested the potential for other cross-reactive allergens. Among patient sera, IgE bound to many different proteins but few had IgE that bound to a protein with common molecular weights across the mite species and this suggested mostly species-specific allergens. Antiserum built to each mite species precipitated one protein in shrimp extracts that bound anti-Der p 10 (tropomyosin) and IgE in the serum pool. Anti-Der p 10 showed strong binding to shrimp tropomyosin but very little to any of the mite proteins. ELISA showed the mite extracts contained very little tropomyosin. The storage and dust mites investigated contain mostly species-specific allergens and very small amounts of the pan-allergen tropomyosin compared to shrimp and snail.     

人血管能抑素基因的克隆、表达及其表达产物的纯化和生物活性测定

以人胎盘脐带组织为材料,提取组织总RNA,用netRTPCR方法合成人血管能抑素cDNA基因,将该cDNA克隆进pSP72载体获得重组质粒pSP72C, DNA序列分析结果与预期序列一致。用BamHⅠ和NdeⅠ双酶切,切下pSP72C上的血管能抑素cDNA,插入pET3c载体的相应位点获得重组表达质粒pETC, 转化E. coli BL21(DE3), SDSPAGE分析显示：在IPTG诱导下,血管能抑素基因获得了高效表达,表达量约占菌体总蛋白的 27.9 %,主要以包涵体形式存在。包涵体经过洗涤、裂解、蛋白复性以及Sephadex G75凝胶过滤层析等步骤后,获得了纯度达91.4 %的人血管能抑素。CAM实验证明10 μg纯化蛋白就能显著抑制鸡胚新生血管生成。     

Vascular volumes and hematology in male and female runners and cyclists

To examine the hypothesis that foot-strike hemolysis alters vascular volumes and selected hematological properties is trained athletes, we have measured total blood volume (TBV), red cell volume (RCV) and plasma volume (PV) in cyclists (n = 21) and runners (n = 17) and compared them to those of untrained controls (n = 20). TBV (ml x kg(-1)) was calculated as the sum of RCV (ml x kg(-1)) and PV (ml x kg(-1)) obtained using 51Cr and 125I-labelled albumin, respectively. Hematological assessment was carried out using a Coulter counter. Peak aerobic power (VO2peak) was measured during progressive exercise to fatigue using both cycle and treadmill ergometry. RCV was 15% higher (P < 0.05) in male cyclists [35.4 (1.0), mean (SE); n = 12] and runners [35.3 (0.98); n = 9] compared to the controls [30.7 (0.92); n = 12]. Similar differences existed between the female cyclists [28.2 (2.1); n = 9] and runners [28.4 (1.0); n = 8] compared to the untrained controls [24.9 (1.4); n = 8]. For the male athletes, PV was between 19% (cyclists) and 28% (runners) higher (P < 0.05) in the trained athletes compared to the untrained controls. The differences in PV between the female groups were not significant. Although the males had a higher (P < 0.05) TBV, RCV and PV than the females, no differences between cyclists and runners were found for either gender. Mean cell volume was not different between the athletic groups. VO2peak (ml x kg(-1) x min(-1)) was higher (P < 0.05) in both male [68.4 (1.5)] and female [54.8 (2.1)] runners when compared to the untrained males [47.1 (1.0)] and females [40.5 (2.1)]. Although differences existed between the genders in VO2peak for both cyclists and runners, no differences were found between the athletic groups within a gender. Since the vascular volumes were not different between cyclists and runners for either the males or females, foot-strike hemolysis would not appear to have an effect on that parameter. The significant correlations (P < 0.05) found between VO2peak and RCV (r = 0.64 and 0.64) and TBV (r = 0.82 and 0.63) for the males and females, respectively, suggests a role for the vascular system in realizing a high aerobic power.