Effects of local density and flower colour polymorphism on pollination and reproduction in the rewardless orchid Dactylorhiza sambucina (L.) Soò

The rewardless orchid Dactylorhiza sambucina shows a stable flower colour polymorphism, with both yellow- and red-flowered morphs growing sympatrically. Pollination biology and breeding system were investigated to examine the effects of density of plants, colour polymorphism, inflorescence dimension, and flower position within inflorescence on male and female reproductive success in three natural populations of D. sambucina. There were significant differences among sites in the number of pollinia removed and in fruit set per inflorescence. Number of removed pollinia and capsule production in D. sambucina were independent from flower and inflorescence size or flower position. As a whole, the red morphs showed the highest number of capsules produced, while the yellow morphs had the greatest male success. The relative male and female reproductive success were independent from plant density but were significantly correlated with the yellow morph frequency at the population level. Overall, our findings show that the contribution to the total reproductive success deriving from the two colour morphs does not conform with the predictions of negative frequency-dependent selection.     

Correlation between the parameters of contingent negative variation and characteristics of variational pulsometry in Parkinsonian patients

In patients suffering from Parkinson's disease (PD), we analyzed correlations between the parameters of contingent negative variation (CNV) and data of variational pulsometry (according to the measurements of R-R ECG intervals). Studies were carried out on 35 patients (group PD), 49 to 74 years old, with the stage of disease of 1.5 to 3.0 according to the Hoehn-Yahr international classification. In the course of CNV recording (i.e., in the state of a certain functional loading), we observed significant negative correlations between the integral magnitude (area) of this potential and indices of variational pulsometry (RMSSD, SDNN, C. var, and HF) that characterize the intensity of parasympathetic (respiratory) influences on the cardiovascular system. In the control group, such correlations were absent. We found significant correlations between the autonomic balance, CNV magnitude, and stage of PD reflecting the level of generalization of the pathological process. In the subgroup of patients with the PD stage 1.5 to 2.0, significant changes in the mean values of indices of parasympathetic influences during recording of the CNV were not observed, while in another subgroup (the PD stage 2.5 to 3.0), these values increased significantly (P < 0.05 and P < 0.01). If the estimates of the PD stage were low, the CNV area demonstrated greater values (P < 0.01). The disturbance of coordination of muscle-to-muscle interactions in the PD group is, probably, an important factor responsible for parasympathetic dysregulation and suppression of the CNV generation. We found positive correlation between the intensity of parasympathetic influences in the course of CNV recording and the level of postural disorders (r = 0.37, P < 0.05). On the contrary, the CNV magnitude demonstrated a negative correlation with the intensity of these disorders (r = −0.36, P < 0.05), as well as with the level of postural instability (r = −0.55, P < 0.001). We hypothesize that alterations of the autonomic balance and the activity of those cerebral structures, which are responsible for the motor readiness, result, to a significant extent, from weakening of the activity of the noradrenergic system due to degenerative processes developing in cells of the locus coeruleus. The impairment of the latter structure, together with degeneration of neurons of the substantia nigra and a decrease in the level of nigro-striatal dopamine, underlies the pathomorphological pattern of PD. Neirofiziologiya/Neurophysiology, Vol. 40, No. 3, pp. 242–253, May–June, 2008.     

The role a botanical institute can play in the conservation of the terrestrial biodiversity in a developing country

The need to integratein situ conservation into the planning process is outlined, and the importance of vegetation survey to determine conservation priorities and to identify areas suitable forin situ conservation is stressed. A case is presented, drawing on experience gained in Zimbabwe, of how a botanical institute can become an integral part of biological conservation. The institute should consist of a herbarium, a botanical garden, a gene bank and a vegetation survey unit. The function of each section, how they interlink, and how they can be integrated are discussed.     

Patterns of co‐occurrences in a killifish metacommunity are more related with body size than with species identity

Body size may be more important than species identity in determining species interactions and community structure. However, co‐occurrence of organisms has commonly been analysed from a taxonomic perspective and the body size is rarely taken into account. On six sampling occasions, we analysed patterns of killifish co‐occurrences in nestedness (tendency for less rich communities to be subsamples of the richest), checkerboard structure (tendency for species segregation), and modularity (tendency for groups to co‐occur more frequently than random expectation) in a pond metacommunity located in Uruguay. We contrasted co‐occurrence patterns among species and body size‐classes (individuals from different species were combined into size categories). The analysis was performed at two spatial scales: ponds (communities) and sample units within ponds. Observed nestedness was frequently smaller than the null expectation, with significantly greater deviations for body size‐classes than for species, and for sample units than for communities. At the sample unit level, individuals tended to segregate (i.e. clump into a checkerboard pattern) to a larger extent by body size rather than by taxonomy. Modularity was rarely detected, but nevertheless indicated a level of taxonomic organization not evident in nestedness or checkerboard indices. Identification of the spatial scale and organization at which ecological forces determine community structure is a basic requirement for advancement of robust theory. In our study system, these ecological forces probably structured the community by body sizes of interacting organisms rather than by species identities.     

县域城镇空间形态与居住建筑能耗关联性的连续尺度研究——以浙江长兴、福建连江为例

居住建筑能耗受建筑周边空间形态的直接影响，确定空间形态低碳效应及其最佳尺度将有助于实现县域城镇低碳转型。以浙江省长兴县、福建省连江县为例，共计选取49个具有代表性的居住建筑样本，采用GIS分析与数理统计相结合的方式，在居住建筑1800m半径范围内，以200m为间隔建立缓冲区，开展全年、最冷月份能耗期及最热月份能耗期建筑能耗与周边空间形态关联性的连续尺度研究。结果表明：(1)道路密度、开发密度、容积率均与建筑能耗呈正相关，但各指标对应的能耗时期、尺度范围有较大差异。(2)水面率、土地利用混合度是与建筑能耗相关的共性指标，但在不同地区的正负效应及尺度范围不同；(3)影响浙闽地区县域城镇最热月份能耗期能耗的关键形态因子为1000m-道路密度、800m-水面率、1600m-开放空间率；影响连江最冷月份能耗期能耗的关键形态因子为800m-水面率。(4)就控碳单元设置而言，长兴县可重点关注1000—1200m半径范围，连江县可重点关注800—1000m、1400m半径范围。(5)浙闽地区县域城镇特性指标为开放空间率，与最热月份能耗期建筑能呈负相关；长兴县特性指标为容积率、水岸密度，分别与全年、最冷...     

Biomechanical rationale of coronary artery bypass grafting of multivessel disease

The biomechanical model of human coronary arteries was modified for improving the quality of diagnosis and surgical treatment for coronary heart disease. The problem of hemodynamics in the left coronary artery with multivessel bed disease – 45% stenosis of the anterior descending branch and 75% stenosis of the circumflex branch – was particularly considered. Numerical simulation of the coronary arterial bypass of the main trunk was carried out to estimate the functional condition of the coronary arteries after restoring myocardial blood supply by surgery.     

An artificial osmotic cell: a model system for simulating osmotic processes and for studying phenomena of negative pressure in plants

Abstract An artificial osmotic cell has been constructed using reverse osmosis membranes. The cell consisted of a thin film of an osmotic solution (thickness: 100 to 200 μm) containing a non-permeating solute and was bounded between the membrane and the front plate of a pressure transducer which continuously recorded cell turgor. The membrane was supported by metal grids to withstand positive and negative pressures (P). At maximum, negative pressures of up to –0.7 MPa (absolute) could be created within the film on short-term and pressures of up to –0.3 MPa could be maintained without cavitation for several hours. As with living plant cells, the application of osmotic solutions of a non-permeating solute resulted in monophasic relaxations of turgor pressure from which the hydraulic conductivity of the membrane (Lp) and the elastic modulus of the cell (?) could be estimated. The application of solutions with permeating solutes resulted in biphasic pressure relaxation curves (as for living cells) from which the permeability (P_s) and reflection (σ_s) coefficients could be evaluated for the given membrane. Lp, P_s, and σ_s were independent of P and did not change upon transition from the positive to the negative range of pressure. It is concluded that the artificial cell could be used to simulate certain transport properties of living cells and to study phenomena of negative pressure as they occur in the xylem and, perhaps, also in living cells of higher plants.