COMPARISON OF MASTICATORY MORPHOLOGY BETWEEN RHINOPITHECUS-BIETI AND R-ROXELLANA

The masticatory apparatus for two endemic species of golden monkey in China, Rhinopithecus bieti and Rhinopithecus roxellana, were compared with those of macaques, Macaca and leaf monkeys, Presbytis. Multivariate analyses demonstrated that the two golden monkey species are distinct. Interspecies allometric analyses revealed that golden monkeys differ in their masticatory apparatus from both macaques and leaf monkeys. The prominent symphysial fusion, corpus, and sagittal condylar dimension of R. roxellana may produce efficient biting force on the incisal and posterior canine teeth, with the heavy reaction force barn on the temporomandibular joint. However, the well-developed bizygamatic width and mandibular height in R. bieti suggest that posterior canine function is similarly prominent in R. roxellana, while incisal function is not. (C) 1995 Wiley-Liss, Inc.

Habitat degradation of Rhinopithecus bieti in Yunnan, China

Black-and-white snub-nosed monkeys (Rhinopithecus bieti) are endemic to the Trans-Himalayas in Northwest Yunnan and Southeast Tibet between the upper Yangtze and Mekong Rivers. Based on field surveys and previous reports, we identified the dark-coniferous forest, the mixed coniferous and broadleaf forest, and oak patches as suitable habitats (SH) for the monkeys. Summer grazing lands (SGL), which were made by local people cutting and burning the dark-coniferous forest at the high altitude belt, replaced SH. To have a general view of the status of the SH in Yunnan, we estimated the areas of SH and SGL from satellite images in 1997, and compared with areas estimated from aerial photo-based maps (ca. 1958). The work resulted in: 1) the area of SH was 4,169 km(2) in 1997; 2) SGL was 1,923 km(2); 3) during the past 40 years, the area of SH decreased by 31% (1,887 km(2)), and SGL increased by 204% (1,291 km(2)); and 4) the mean size of forest patches decreased from 15.6 to 5.4 km(2). In addition, the area of SGL is positively correlated to local human population (R-2 greater than or equal to0.53), implying that the reduction and fragmentation of habitat for Rhinopithecus bieti is a result of population growth of humans, who mostly employ traditional modes of production. Only 11 monkey groups remained in the changing habitat. Considering that forests at lower elevation were also encroached upon by farmlands in a similar way, the forest ecosystem is highly threatened. The destruction will continue unless there is a change in the mode of production in the region.

Thylakoid terminal oxidases are essential for the cyanobacterium Synechocystis sp. PCC 6803 to survive rapidly changing light intensities.

Cyanobacteria perform photosynthesis and respiration in the thylakoid membrane, suggesting that the two processes are interlinked. However, the role of the respiratory electron transfer chain under natural environmental conditions has not been established. Through targeted gene disruption, mutants of Synechocystis sp. PCC 6803 were generated that lacked combinations of the three terminal oxidases: the thylakoid membrane-localized cytochrome c oxidase (COX) and quinol oxidase (Cyd) and the cytoplasmic membrane-localized alternative respiratory terminal oxidase. All strains demonstrated similar growth under continuous moderate or high light or 12-h moderate-light/dark square-wave cycles. However, under 12-h high-light/dark square-wave cycles, the COX/Cyd mutant displayed impaired growth and was completely photobleached after approximately 2 d. In contrast, use of sinusoidal light/dark cycles to simulate natural diurnal conditions resulted in little photobleaching, although growth was slower. Under high-light/dark square-wave cycles, the COX/Cyd mutant suffered a significant loss of photosynthetic efficiency during dark periods, a greater level of oxidative stress, and reduced glycogen degradation compared with the wild type. The mutant was susceptible to photoinhibition under pulsing but not constant light. These findings confirm a role for thylakoid-localized terminal oxidases in efficient dark respiration, reduction of oxidative stress, and accommodation of sudden light changes, demonstrating the strong selective pressure to maintain linked photosynthetic and respiratory electron chains within the thylakoid membrane. To our knowledge, this study is the first to report a phenotypic difference in growth between terminal oxidase mutants and wild-type cells and highlights the need to examine mutant phenotypes under a range of conditions.

Photosynthesis and growth of Arthrospira (Spirulina) platensis (Cyanophyta) in response to solar UV radiation, with special reference to its minor variant

The minor variant of the economically important cyanobacterium, Arthrospira platensis, usually appears in commercial production ponds under solar radiation. However, how sensitive the minor variant to solar UVR and whether its occurrence relates to the solar exposures are not known. We investigated the photochemical efficiency of PSII and growth rate of D-0083 strain and its minor variant in semi-continuous cultures under PAR (400-700 nm) alone, PAR + UV-A (320-400 nm) and PAR + UV-A + UV-B (280-700 nm) of solar radiation. The effective quantum yield of D-0083 at 14:00 p.m. decreased by about 86% under PAR, 87% under PAR + UV-A and 92% under PAR + UV-A + UV-B (280-315 nm), respectively. That of the minor variant was reduced by 93% under PAR and to undetectable values in the presence of UV-A or UV-A + UV-B. Diurnal change of the yield showed constant pattern during long-term (10 days) exposures, high in the early morning and late afternoon but the lowest at noontime in both strains, with the UVR-related inhibition being always higher in the variant than D-0083. During the long-term exposures, cells of D-0083 acclimated faster to solar UV radiation and showed paralleled growth rates among the treatments with or without UVR at the end of the experiment; however, growth of the minor variant was significantly reduced by UV-A and UV-B throughout the period. Comparing to the major strain D-0083, the minor variant was more sensitive to UVR in terms of its growth, quantum yield and acclimation to solar radiation. (c) 2007 Elsevier B.V. All rights reserved.

An in situ estimate of food consumption by icefish in Lake Chaohu, China

The icefish (Neosalanx taihuensis) of Lake Chaohu, China, foraged almost exclusively on crustacean zooplankton in both spring and summer. The icefish showed diurnal feeding periodicity, with peak feeding in the morning. No food was observed in icefish guts collected at night. Our results indicate that that the icefish was a particulate feeder and light intensity greatly affected its foraging on zooplankton. Daily consumption of zooplankton by icefish varied significantly both diurnally and among seasons, which ranged from 0.22 to 2.23 g (wet weight) per 100 g wet fish weight at temperatures between 16.3 degrees C (spring) and 28.8 degrees C (summer).

Daily production and photosynthetic characteristics of Nostoc flagelliforme grown under ambient and elevated CO2 conditions

Diurnal photosynthesis of Nostoc flagelliforme was investigated at varied levels of CO2 concentrations and desiccation in order to estimate the effects of enriched CO2 and watering on its daily production. Photosynthetic activity was closely correlated with the desiccated status of the algal mats, increased immediately after watering, reached a maximum at moderate water loss, and then declined with further desiccation. Increased CO2 concentration enhanced the diurnal photosynthesis and raised the daily production. Watering twice per day enhanced the daily production due to prolonged period of active photosynthesis. The values of daily net production were 1321280 mumol CO2 g (d. wt)(-1) d(-1), corresponding to about 0.6-6.1% daily increase in dry weight. High-CO2-grown mats required higher levels of photon flux density to saturate the alga's photosynthesis in air. Air-grown mats showed higher photosynthetic affinity for CO2 and higher levels of dark respiration compared with high-CO2-grown samples.

黄土高原半干旱区侧柏(Platycladus orientalis)树干液流动态

应用热扩散式树干茎流计(TDP)于2008年4～10月对黄土高原安塞县侧柏人工林树干液流速率进行了连续测定,并对周围气象、土壤水分等多个环境因子进行了同步测定。结果表明:侧柏在不同月份晴天树干液流速率变化具有明显的昼夜节律性,呈单峰曲线;且各月液流速率日均值受土壤供水水平限制总体上呈下降趋势,即4月份最大,为0.00135cm.s-1;10月份最小为0.00011cm.s-1;树干液流速率与光合有效辐射、大气温度、水汽压差呈极显著正相关,与相对湿度呈负相关,其相关程度:光合有效辐射>水汽压差>大气温度>相对湿度,并可用线性表达式来估算;侧柏边材面积和地径呈幂指数关系,并以此结合密度估算出样地侧柏人工林的边材面积为4.65m2,最终估算出侧柏人工林生长季总耗水量为1159.6t.hm-2。

干旱胁迫下本氏针茅光合特性和水分利用效率日动态研究

采用盆栽和人工控制土壤水分的方法,使用Li-6400便携式光合测定系统观测本氏针茅(Stipa bungeana)光合生理生态特征的日变化。结果表明:在不同土壤水分状况下,本氏针茅净光合速率日变化曲线均呈"双峰"型,并有不同程度的"午休"现象,且上午的净光合速率明显高于下午,随着土壤水分的升高而增加;蒸腾速率日变化曲线也呈"双峰"型,表现为较高土壤水分处理针茅具有较高的蒸腾速率;气孔导度受水分和光热胁迫的影响,日变化曲线呈凹型;胞间CO2浓度受空气CO2浓度和气孔导度的双重影响,呈现早晚高,正午低的日变化进程;水分利用效率最高值出现在上午较早的时段,随着土壤水分的增加,水分利用效率却降低。

黄土旱塬区冬小麦不同施肥处理的土壤呼吸及土壤碳动态

依据黄土旱塬区黑垆土上中国科学院长武站长期定位试验(始于1984年),于2008年3月到6月,测定了冬小麦连作系统中返青期、拔节期、抽穗期、灌浆期和收获期土壤呼吸日变化、生育期变化以及土壤可溶性有机碳(Dissolved organic C,DOC)和微生物量碳(Soil microbial biomass C,MBC),研究了施肥措施对土壤呼吸、DOC和MBC的影响以及土壤呼吸与碳组分之间的关系。研究涉及6个处理:休闲地(F)、不施肥(CK)、有机肥(M)、氮肥(N)、氮磷肥(NP)和氮磷有机肥(NPM)。结果表明,冬小麦连作系统中土壤呼吸的日变化格局呈单峰曲线,最高值出现在12:00左右(拔节期)和14:30左右(成熟期),最小值出现在0:00～3:00之间或6:00左右;冬小麦土壤呼吸速率拔节期最高,其次是灌浆后期,抽穗期最低;不同施肥条件下,各生育期土壤呼吸速率大小顺序:NPM>M>NP>N>CK>F。土壤水分亏缺是导致抽穗期和灌浆期土壤呼吸速率降低的重要原因。各施肥处理DOC含量高低顺序为灌浆期>抽穗期>成熟期>返青期>拔节期;除M,NPM处理MBC含量拔节期>灌浆期外,各施肥处理MBC含量高低顺序...

黄土旱塬冬小麦水分利用效率及相关生理特性研究

采用Li-6400便携式光合测定系统在模拟光照条件下,通过对冬小麦叶片生理指标及其相应环境因子的测定,研究了小麦的生理指标和叶片水分利用效率的动态变化规律及其对环境因子的响应。结果表明:净光合速率日变化呈不明显的双峰曲线,蒸腾速率日变化呈明显的倒"U"型曲线,且不同生育期两者峰值出现的时间不同。拔节期环境因子对生理指标的影响要比灌浆期明显的多。光合有效辐射和CO2浓度是对净光合速率和叶片蒸腾速率影响最强烈的环境因子。在小麦整个生长过程中,温湿度对气孔导度的影响在逐渐增大,对胞间CO2浓度的影响也比较明显。小麦叶片水分利用效率的日变化呈不明显的双峰曲线,其峰值出现的时间早于净光合速率和蒸腾速率峰值出现的时间。灌浆期日平均WUE比拔节期低30.5%。小麦净光合速率、蒸腾速率和气孔导度三者之间极显著相关,叶片温度与气孔导度显著负相关。

桃树茎直径变化及其与气象因子关系

用线性差分径向变化仪连续监测充分灌溉条件下的仕女红桃树茎直径变化,结合同步观测的气象因子数据,分析2007年3月中旬～10月下旬的仕女红桃树茎直径变化规律,为基于果树直径变化的灌溉管理提供基础依据。结果表明:仕女红桃树茎直径具有很好的时间变化规律,日变化曲线呈均匀"U"型,日最大值出现在黎明前后,日最小值出现在下午4时左右;季节变化方面,MDS呈低—高—低变化规律,从萌芽—开花期到果实成熟期的不同生长阶段,MDS平均值依次为87μm、200.84μm、253.75μm、171.67μm、138.67μm和94.34μm,坐果—展叶期和第一次果实膨大期MDS值居全生育期最高,需水量最大。桃树直径生长呈慢—快—慢变化规律,3月中下旬,开始生长,平均日生长量从12.68μm逐渐增加大36.84μm,7月24日～8月23日之间生长最快,平均日生长量达73.67μm,然后迅速下降,到生长末期平均日生长量仅为7.36μm。3～5月和7～9月可分别采用DI和MDS作为灌溉控制指标。茎直径变化与气象因子响应强烈,但不同生长阶段对茎直径变化产生主要影响的气象因子不同,对MDS产生主要影响的气象因子依次为:Rn、Tmax、Tma...

黄土高原冬小麦田光谱特征变化及其与二氧化碳日收支的相关分析

根据光谱辐射仪对黄土高原冬小麦整个生育期光谱反射率的连续观测数据及CO2通量观测数据,对冬小麦田光谱特征变化及其与CO2日收支的相关性进行了分析.结果表明:冬小麦田不同波长光谱反射率和归一化植被指数(NDVI)呈现明显的日变化和季节变化.同一天内,反射率随太阳高度角的变化而变化,变化最大的波段(550nm左右、700～1050nm)表现为峰.不同生育期同一时刻,可见光波段(350～670nm)反射率变化不大,近红外波段(700～1050nm)出现较大差异,在出苗期、分蘖期和越冬期后红边位置向长波方向"红移";越冬期前出现向短波方向"蓝移"的现象;但成熟期"蓝移"现象不明显,表现为突变;其他生育时期没有观测到波谱位移.NDVI的日变化呈U型,13:00左右最低,16:00后出现较大波动,与抛物线有较好的拟合效果,小麦生长旺盛时期,对其地面遥感观测应选择在NDVI变化不大的13:00左右进行;整个冬小麦生长季11:00反射率及NDVI以播种后第140天为中心对称,NDVI的季节变化表现为M型,可用四次多项式拟合;在整个小麦生育期中NDVI与CO2的日收支呈极显著负相关,但正午左右的相关性稍差.

中国沙棘、俄罗斯沙棘和俄罗斯沙棘×中国沙棘光合特性及影响因子

在陕北黄土丘陵沟壑区用LI-6400光合仪对中国沙棘、俄罗斯沙棘和俄罗斯沙棘×中国沙棘光合特性及影响因子进行了测定。测定结果表明三者的光合速率、气孔导度、胞间CO2浓度、蒸腾速率日变化均为"双峰"曲线。中国沙棘光合"午休"现象较轻,日光合速率和午后光合速率、气孔导度、胞间CO2浓度、蒸腾速率极显著(p<0.01)高于俄罗斯沙棘和俄罗斯沙棘×中国沙棘。中国沙棘光合作用最适气孔导度、大气CO2浓度、空气相对湿度比俄罗斯沙棘小,最适胞间CO2浓度、蒸腾速率、气温、光合有效辐射比俄罗斯沙棘高。中国沙棘在最适气孔导度、胞间CO2浓度、蒸腾速率和大气CO2浓度下的光合速率比俄罗斯沙棘高;在最适气温、空气相对湿度、光合有效辐射下的光合速率比俄罗斯沙棘低。俄罗斯沙棘×中国沙棘光合"午休"现象比中国沙棘强,比俄罗斯沙棘弱,午后光合速率与俄罗斯沙棘相近;俄罗斯沙棘×中国沙棘最适气孔导度、大气CO2浓度高于中国沙棘和俄罗斯沙棘,最适胞间CO2浓度低于中国沙棘和俄罗斯沙棘,最适蒸腾速率、气温、空气相对湿度、光合有效辐射居于中国沙棘和俄罗斯沙棘之间。俄罗斯沙棘×中国沙棘在最适气孔导度下的光合速率高于中国沙棘和俄罗斯沙棘;在最适胞间CO...

滇金丝猴细菌人工染色体文库构建及Neurotrypsin基因的分子进化研究

本文包括两方面有关灵长类的研究工作。一是构建了一个非人灵长类（滇金丝猴）的人工染色体文库（BAC文库），为进一步研究灵长类的基因组进化奠定了一定的基础，二是对一个认知相关基因neuotrypsin在灵长类中的分子进化进行了详尽的研究，以期从分子进化角度认识该基因在灵长类高级认知功能发展中所起的作用。滇金丝猴（Rhinopithecusbieti），一个处于严重濒危状态的旧大陆猴，中国特产灵长类之一。在系统发育上它占据着旧大陆猴与小猿的中间地位，是研究灵长类进化的一个重要物种。，在本研究中，我们构建了一个滇金丝猴的细菌人工染色体文库（BAC文库）。该文库含有136320个BAC克隆，平均插入片段大小为148kb，小片段（50-100kb）所占的比例为2.74％，非重组克隆仅占2.67％。假定金丝猴与亲缘关系较近的灵长类有着相似的基因组大小，该文库至少有6倍的基因组覆盖率。对随机选取的BAC克隆进行末端测序，我们获得了201个序列标签（STS）。通过荧光原位杂交（FISH）技术，139个经末端测序的BAC克隆被精确定位到滇金丝猴的染色体上。荧光杂交实验还表明了人和金丝猴染色体产存在着高度的同线保守性。在人类基因组数据库中的Blast搜寻的结果显示染色体上的克隆数目与染色体大小呈很好的相关性，表明该文库克隆比较均匀地覆盖了滇金丝猴的基因组。该金丝猴文库及所定位的克隆将会成为非人灵长类的比较基因组研究和大规模基因组测序的一个宝贵的资源。Neurotrypsin是与个主要在脑中表达的，同神经发育和认知功能相关的胞外丝氨酸蛋白酶。它在人体中发生的突变与常染色体上隐性的非综合性精神发育迟缓（MR）紧密相关。我们通过对n个非人灵长类，包括大猿、小猿、旧大陆猴和新大陆猴neurotrypsin的编码区的测序，研究了neurotrypsin在灵长类中的分子进化。结果显示出，在灵长类进化过程中，neurotrypsin保持着由纯化性选择（负沟选择）所致的强烈的功能限制，这暗示着neurotrypsin在灵长类的认知发展中起着关键的功能性作用。进一步的分析表明，纯化性选择实际上只作用于neurotrypsin的介导其结合到其它细胞表面或胞外蛋白质的SRCR功能结构域上。另外，通过灵长类和其它哺乳动物目的比较，我们还发现，在鼠neuotrypsin中，一个人SRCR结构域（外显子2和3）的缺失是由于在鼠科动物中所发生的片段丢失事件所致。