Light response in seedlings of a temperate (<Emphasis Type="Italic">Quercus petraea</Emphasis>) and a sub-Mediterranean species (<Emphasis Type="Italic">Quercus pyrenaica</Emphasis>): contrasting ecological strategies as potential keys to regeneration performance in mixed marginal populations

In order to understand better the ecology of the temperate species Quercus petraea and the sub-Mediterranean species Quercus pyrenaica, two deciduous oaks, seedlings were raised in two contrasting light environments (SH, 5.3% full sunlight vs. HL, 70% full sunlight) for 2 years, and a subset of the SH seedlings were transferred to HL (SH–HL) in the summer of the second year. We predicted that Q. pyrenaica would behave more as a stress-tolerant species, with lower specific leaf area (SLA), allocation to leaf mass, and growth rate and less responsiveness to light in these metrics, than Q. petraea, presumed to be more competitive when resources, especially light and water, are abundant. Seedlings of Q. petraea had larger leaves with higher SLA, and exhibited a greater relative growth rate (RGR) in both SH and HL. They also displayed a higher proportion of biomass in stems (SMF), and a lower root to shoot ratio (R/S) in HL than those of Q. pyrenaica, which sprouted profusely, and had higher rates of photosynthesis (A_n) and stomatal conductance (g_wv), but lower whole-plant net assimilation rate (NAR). On exposure to a sudden increase in light, SH–HL seedlings of both species showed a short period of photoinhibition, but fully acclimated photosynthetic features within 46 days after transference; height, main stem diameter, RGR and NAR all increased at the end of the experiment compared to SH seedlings, with these increases more pronounced in Q. petraea. Observed differences in traits and responses to light confirmed a contrasting ecology at the seedling stage in Q. petraea and Q. pyrenaica in consonance with differences in their overall distribution. We discuss how the characteristics of Q. petraea may limit the availability of suitable regeneration niches to microsites of high-resource availability in marginal populations of Mediterranean climate, with potential negative consequences for its recruitment under predicted climatic changes.     

Evolutionary and environmental determinants of freshwater fish thermal tolerance and plasticity

Understanding the extent to which phylogenetic constraints and adaptive evolutionary forces help define the physiological sensitivity of species is critical for anticipating climate‐related impacts in aquatic environments. Yet, whether upper thermal tolerance and plasticity are shaped by common evolutionary and environmental mechanisms remains to be tested. Based on a systematic literature review, we investigated this question in 82 freshwater fish species (27 families) representing 829 experiments for which data existed on upper thermal limits and it was possible to estimate plasticity using upper thermal tolerance reaction norms. Our findings indicated that there are strong phylogenetic signals in both thermal tolerances and acclimation capacity, although it is weaker in the latter. We found that upper thermal tolerances are correlated with the temperatures experienced by species across their range, likely because of spatially autocorrelated processes in which closely related species share similar selection pressures and limited dispersal from ancestral environments. No association with species thermal habitat was found for acclimation capacity. Instead, species with the lowest physiological plasticity also displayed the highest thermal tolerances, reflecting to some extent an evolutionary trade‐off between these two traits. Although our study demonstrates that macroecological climatic niche features measured from species distributions are likely to provide a good approximation of freshwater fish sensitivity to climate change, disentangling the mechanisms underlying both acute and chronic heat tolerances may help to refine predictions regarding climate change‐related range shifts and extinctions.     

The total burden of rare,non-synonymous exome genetic variants is not associated with childhood or late-life cognitive ability

Human cognitive ability shows consistent, positive associations with fitness components across the life-course. Underlying genetic variation should therefore be depleted by selection, which is not observed. Genetic variation in general cognitive ability (intelligence) could be maintained by a mutation–selection balance, with rare variants contributing to its genetic architecture. This study examines the association between the total number of rare stop-gain/loss, splice and missense exonic variants and cognitive ability in childhood and old age in the same individuals. Exome array data were obtained in the Lothian Birth Cohorts of 1921 and 1936 (combined N = 1596). General cognitive ability was assessed at age 11 years and in late life (79 and 70 years, respectively) and was modelled against the total number of stop-gain/loss, splice, and missense exonic variants, with minor allele frequency less than or equal to 0.01, using linear regression adjusted for age and sex. In both cohorts and in both the childhood and late-life models, there were no significant associations between rare variant burden in the exome and cognitive ability that survived correction for multiple testing. Contrary to our a priori hypothesis, we observed no evidence for an association between the total number of rare exonic variants and either childhood cognitive ability or late-life cognitive ability.     

Sex differences in leg dexterity are not present in elite athletes

We studied whether the time-varying forces that control unstable foot–ground interactions provide insight into the neural control of dynamic leg function. Twenty elite (10 F, 26.4 ± 3.5 yrs) and 20 recreational (10 F, 24.8 ± 2.4 yrs) athletes used an isolated leg to maximally compress a slender spring designed to buckle at low forces while seated. The foot forces during the compression at the edge of instability quantify the maximal sensorimotor ability to control dynamic foot–ground interactions. Using the nonlinear analysis technique of attractor reconstruction, we characterized the spatial (interquartile range IQR) and geometric (trajectory length TL, volume V, and sum of edge lengths SE) features of the dynamical behavior of those force time series. ANOVA confirmed the already published effect of sex, and a new effect of athletic ability, respectively, in TL (p = 0.014 and p < 0.001), IQR (p = 0.008 and p < 0.001), V (p = 0.034 and p = 0.002), and SE (p = 0.033 and p < 0.001). Further analysis revealed that, for recreational athletes, females exhibited weaker corrective actions and greater stochasticity than males as per their greater mean values of TL (p = 0.003), IQR (p = 0.018), V (p = 0.017), and SE (p = 0.025). Importantly, sex differences disappeared in elite athletes. These results provide an empirical link between sex, athletic ability, and nonlinear dynamical control. This is a first step in understanding the sensorimotor mechanisms for control of unstable foot–ground interactions. Given that females suffer a greater incidence of non-contact knee ligament injuries, these non-invasive and practical metrics of leg dexterity may be both indicators of athletic ability, and predictors of risk of injury.     

A general approach to the concept of varietal ability for synthetic varieties

Summary Genetic effects for varietal value are defined at the level of the population of k-parent synthetic varieties. A simple expression for the total variance among synthetics arises directly from these definitions. A general expression for the covariance among related synthetics is given. Genetic effects are also defined in a completely general way so as to allow for any system of testing and used to derive an expression for the genetic advance in recurrent selection for varietal value. Covariances between relatives evaluated in the system of testing and in varietal combination are introduced, allowing a direct expression of the genetic advance in varietal development when parents are selected either individually or in groups. Some general implications for plant breeding are outlined.Dedicated to Professor F.W. Schnell on the occasion of his 65th birthday     

The Analysis of Partial Diallel Crosses

The analysis of offsprings from the partial diallel crosses is presented. In considered type of crossing, p parental forms into H separate groups are devided. Single crosses among parental forms, from separate groups only, are performed. The analysis for experiments laid out in efficiency balanced block designs is given.     

城市群生态安全格局构建:概念辨析与理论思考

城市群是城市发展到一定阶段通过城市间物流、人流和能流高度融合而形成的区域性复合生态系统，如何保障城市群生态安全与健康发展成为当前关注的热点问题。本研究系统分析了生态安全、城市生态安全与城市群生态安全的内涵。认为狭义上城市群生态安全侧重于城市群内部生态空间优化和生态系统服务功能提升，重点关注城市群地区生态用地空间优化与"三生空间"（生态、生活及生产空间）的合理布局。广义上的城市群生态安全不仅需要考虑城市群内部生态系统结构和功能协调及其生态系统服务的供需平衡，也需要从区域尺度考虑城市群与其他区域之间的协调关系。城市群生态安全格局构建的目的则是保障城市群内部区域一体化协调发展，满足人们日常生活的基本需求，实现城市群与区域之间物流、能流和人流的有序流通。在城市群生态安全格局构建时，除了遵循生态安全一般性原则外，还需要遵循以下原则：①生态系统服务供需平衡尺度效应；②生态安全保障的阈值效应；③生态安全格局的空间联动效应。最后文章提出了城市群生态安全格局构建的基本思路和技术路径。     

Extraction of defatted rice bran by subcritical water treatment

Defatted rice bran was treated with subcritical water in the temperature range of 180–280 °C for 5 min using 117 mL and 9 mL vessels to produce the extracts. The total sugar and protein contents and radical scavenging activity of the extracts were then estimated for both vessels. The total sugar concentration of ca. 0.3 g/L-extract was the highest for the extracts at 200 °C, and it significantly decreased at the higher temperatures. The protein concentration and radical scavenging activity were higher at the higher temperatures. Extraction was also done at 200 °C and 260 °C for various times using the small vessel. The total sugar concentration decreased with the increasing extraction time, while the protein concentration and radical scavenging activity only slightly depended on the extraction time. The extracts at 200 °C or lower temperatures using the large vessel possessed the emulsifying and emulsion-stabilizing activities. The HPLC analysis of the extract at 260 °C for 5 min using the small vessel indicated that it contained both hydrophilic and hydrophobic substances. The hydrophilic fraction of the extract mainly contained low-molecular-mass substances.     

Characterization of Ser73 in Arabidopsis thaliana Glutathione S-transferase zeta class

Glutathione S-transferases (GSTs) are ubiquitous detoxifying superfamily enzymes. The zeta class GST from Arabidopsis thaliana (AtGSTZ) can efficiently degrade dichloroacetic acid (DCA), which is a common carcinogenic contaminant in drinking water. Ser73 in AtGSTZ is a conserved residue at Glutathione binding site (G-site). Compared with the equivalent residues in other GSTs, the catalytic and structural properties of Ser73 were poorly investigated. In this article, site-saturation mutagenesis was performed to characterize the detailed role of Ser73. The DCA de.chlorinating (DCA-DC) activity showed that most of the mutants had less than 3% of the wild-type activity, except S73T and $73A showing 43.48% and 21.62% of the wild-type activity, respectively, indicating that position 73 in AtGSTZ showed low mutational substitutability. Kinetic experiments revealed that mutants S73T, $73A, and S73G showed low binding affinity and catalytic efficiency toward DCA, 1.8-, 3.1-, and 10.7- fold increases in KmDcA values and 4.0-, 9.6-, and 34.1- fold decreases in KcatDCA/KmDCA values, respectively, compared to the wild type. Thermostability and refolding experiments showed that the wild type maintalned more thermostability and recovered activity. These results demonstrated the important role of Set73 in catalytic activity and structural stability of the enzyme. Such properties of Set73 could be particularly crucial to the molecular evolution of AtGSTZ and might,therefore, help explain why Ser73 is conserved in all GSTs. This conclusion might provide insights into the directed evolution of the DCA-DC activity of AtGSTZ.