四川森林植被碳储量的时空变化

利用平均木法建立森林生物量与蓄积量模型,结合四川森林资源二类调查数据,研究了森林碳密度和碳储量的时空变化.结果表明 四川森林碳储量从1974年的300.02 Tg增加到2004年的469.96 Tg,年均增长率1.51%,表明其是CO2的"汇".由于人工林面积的增加,森林植被的平均碳密度从49.91 Mg·hm-2减少到37.39 Mg·hm-2.四川森林碳储量存在空间差异性,表现为川西北高山峡谷区＞川西南山区＞盆周低山区＞盆地丘陵区＞川西平原区.森林碳密度由东南向西北呈现逐渐增加趋势,即盆地丘陵区＜川西平原区＜川西南山区＜盆周低山区＜川西北高山峡谷区.通过分区森林经营与管理将提高四川森林的碳吸存能力.     

南方红壤丘陵区油桐人工林土壤水分动态

利用时域反射仪(TDR)定位监测方法,研究了南方红壤丘陵区油桐人工林土壤水分动态规律.结果表明:不同月份间土壤蓄水量差异达极显著水平,研究时段内土壤水分动态变化可划分为土壤水分积累期、土壤水分消耗期和土壤水分稳定期3个时期;油桐人工林土壤水分垂直变化显著,且不同季节的变化规律各异;土壤蓄水量与大气相对湿度(RH)、大气温度(t)、饱和水汽压差(VPD)、降雨量(R)等气象因子显著相关(P<0.05); 次降雨后,土壤水分损失率与干旱天数呈显著的双曲函数关系,土壤蓄水量与雨后干旱天数呈显著的线性负相关(P<0.05);在次降雨后的持续干旱条件下,土壤水分损失随着土层深度的增加逐渐趋于平缓.     

根茎克隆植物羊草体内可溶性碳水化合物的时间变异及其对去叶干扰的响应

该研究针对根茎型克隆植物羊草(Leymus chinensis)考察了以下内容:1)地上枝条和根茎中可溶性碳水化合物含量的时间动态及其对去叶干扰的响应;2)特定阶段植物体内一定部位的可溶性碳水化合物浓度差异;3)植物体各部分(地上部分、直立茎地下部分及根茎)间可溶性碳水化合物浓度变化之间的关联。基于上述研究结果,作者试图弄清碳水化合物对于羊草克隆分株和整个基株生长和存活的意义。实验共有4个处理:1个对照和3个不同频度(在整个实验进行期间分别去叶1次、3次和5次)的去叶处理。所有去叶处理都采取一个统一的强度,即留茬15 cm。地上枝条和根茎的取样频次为每10 d 1次。植物体各部分可溶性碳水化合物浓度以高效液相色谱法(HPLC)测定。对不同去叶频度处理间的碳水化合物含量差异显著性进行ANOVA分析。结果表明:不去叶对照处理在生长季盛期可溶性碳水化合物浓度的显著下降归因于植物体快速的生长而引起植物叶片旺盛的呼吸消耗,而去叶处理中植物的可溶性碳水化合物浓度并没有大的降低甚至在最频繁的去叶处理下还有所上升,主要是由于去叶处理减少叶片而造成地上部分总呼吸量下降所致。一次性去叶处理并没有影响植物地上部分最终的可溶性碳水化合物浓度,但是连续数次的去叶处理对地上部分可溶性碳水化合物浓度产生了一定的影响。在秋季气温下降时,碳水化合物自地上向地下的转移在去叶频度越大的处理下表现越为迅速。这表明当植物体接受到气温降低的信号后,去叶干扰加速碳水化合物自地上向地下的转移。可能由于地下枝条存在一定的贮藏功能,在实验过程中地下枝条中可溶性碳水化合物浓度比地上枝条中表现的更加稳定。根茎中的可溶性碳水化合物必要时会转移到地上以供应地上枝条的生长,而旺盛的生长会消耗可溶性碳水化合物,然而自未接受去叶处理的分株向接受去叶处理的分株的克隆整合(常常在较高频次的去叶处理中发生)可能会在一定程度上缓解这种消耗所造成的影响。     

葡萄贮期脱落酸（ABA）变化的研究

试验研究了葡萄贮期脱落酸 ( ABA)的变化 ,结果表明 :葡萄贮期 ABA含量呈抛物线形变化 ,有明显的高峰出现 ,低温 ( 0± 0 .5℃ )贮藏具有推迟 ABA峰期和降低峰值的作用 ,经用 9种植物生长调节剂和 2种化学药品对葡萄果穗处理试验 ,三碘苯甲酸 ( TIBA)对 ABA的形成有极强的抑制作用 ,吲哚 - 3-乙酸 ( IAA)、赤霉素 ( GA3)、萘乙酸 ( NAA)和 6-苄基氨基嘌呤 ( 6- BA)对 ABA的形成也具有拮抗作用 ,矮壮素 ( CCC)、比久 ( B9)、乙烯利 ( CEPA)和外源脱落酸对 ABA的形成有促进作用。     

Carnitine is a pharmacological allosteric chaperone of the human lysosomal α-glucosidase

Pompe disease is an inherited metabolic disorder due to the deficiency of the lysosomal acid α-glucosidase (GAA). The only approved treatment is enzyme replacement therapy with the recombinant enzyme (rhGAA). Further approaches like pharmacological chaperone therapy, based on the stabilising effect induced by small molecules on the target enzyme, could be a promising strategy. However, most known chaperones could be limited by their potential inhibitory effects on patient’s enzymes. Here we report on the discovery of novel chaperones for rhGAA, L- and D-carnitine, and the related compound acetyl-D-carnitine. These drugs stabilise the enzyme at pH and temperature without inhibiting the activity and acted synergistically with active-site directed pharmacological chaperones. Remarkably, they enhanced by 4-fold the acid α-glucosidase activity in fibroblasts from three Pompe patients with added rhGAA. This synergistic effect of L-carnitine and rhGAA has the potential to be translated into improved therapeutic efficacy of ERT in Pompe disease.     

脐橙果实贮藏过程中主要有机物质含量的变化

对朋那脐橙、纽荷尔脐橙和红肉脐橙果实采后室温贮藏过程中主要有机物质含量进行分析,结果表明,贮藏期间,果实可溶性固形物含量10d前略有上升,10d后的变化各品种间有差异;可滴定酸含量显著下降;固酸比显著上升;维生素C含量变化趋势因品种而异;可溶性蛋白质含量在贮藏过程中呈上升趋势。上述各指标在贮藏各时期不同品种间有明显差异。     

Dog as a model in studies on human hereditary diseases and their gene therapy

During the last 15 years spectacular progress has been achieved in knowledge on the dog genome organization and the molecular background of hereditary diseases in this species. A majority of canine genetic diseases have their counterparts in humans and thus dogs are considered as a very important large animal model in human biomedicine. Among canine monogenic diseases with known causative gene mutations there are two large groups classified as retinal dystrophies and lysosomal storage diseases. Specific types of these diseases are usually diagnosed in a single or several breeds. A well known disorder, restricted to a single breed, is congenital stationary night blindness described in Briards. This disease is a counterpart of Leber amaurosis in children. On the other hand, one of the most common monogenic human diseases (Duchenne muscular dystrophy), has its canine counterparts in several breeds (e.g., the Golden retriever, Beagle and German short-haired pointer). For some of the canine diseases gene therapy strategy was successfully applied, e.g., for congenital stationary night blindness, rod-cone dystrophy and muccopolysaccharydoses type I, IIIB and VII. Since phenotypic variability between the breeds is exceptionally high, the dog is an interesting model to study the molecular background of congenital malformations (e.g., dwarfism and osteoporosis imperfecta). Also disorders of sexual development (DSD), especially testicular or ovotesticular DSD (78,XX; SRY-negative), which is widely distributed across dozens of breeds, are of particular interest. Studies on the genetic background of canine cancers, a major health problem in this species, are also quite advanced. On the other hand, genetic studies on canine counterparts of major human complex diseases (e.g., obesity, the metabolic syndrome and diabetes mellitus) are still in their infancy.     

The structure and function of the genitalia in the Libellulidae (Odonata)

An outline of the morphology of the secondary genitalia of libellulid dragonflies is given together with a more detailed treatment of the components of the fourth (distal) segment of the penis. The variations of penis structure in 70 species, representing ten of the 11 subfamilies, are surveyed and catalogued. There is remarkable diversity in the presence and form of penis structures, particularly those associated with the medial process, namely the flagelium, cornua and inner lobes. A comparable survey of females shows that they can be provisionally divided into ten types according to the number and size of their sperm-storage organs. Comparisons of penis structures with the sperm-storage organs of females suggests that in species whose females store large amounts of sperm, usually doing so in one or a pair of organs, males possess highly extensible, lobate and bristly penes, commonly equipped with cornua. By contrast, in those species in which the females store small volumes of sperm, usually doing so in three organs, the penes bear either flagella equipped with proximally directed spines or with large terminal barbs, or they have narrow, spiny inner-lobes which resemble flagella. Some functional interpretations are proposed in the light of sperm competition. The variability of genital structure can be interpreted adaptively and does not closely reflect phylogenetic relationships. Functionally convergent structures have evolved a number of times from different origins.     

Intraspecies evolution of enzymic mechanisms associated with the synthesis of α-1,4 storage glucans in two thermophilic-acidophilic algae of Cyanidium type

Cyanidium caldarium is an enigmatic eukaryotic alga which is both acidophilic and thermophilic. Its taxonomic position has been in doubt and, hence