Leaf expansion of four sunflower (Helianthus annuus L) cultivars in relation to water deficits. I. Patterns during plant development

Abstract. The influence of a slow stress and recovery cycle on the pattern of leaf expansion in four diverse sunflower cultivars ( Helianthus annuus L. cvs. Hysun 31, Havasupai, Hopi and Seneca) was studied in a glasshouse. Stress had no significant effect on the time of flower bud emergence and anthesis, or on final leaf number, but delayed the appearance of leaves at high insertions in all cultivars except Hysun 31.
Leaf expansion was markedly reduced as the predawn leaf water potential decreased from −0.35 to −0.60 MPa, and the predawn turgor pressure decreased from 0.3 to 0.2 MPa, and expansion ceased at a predawn leaf water potential of about −1.0 MPa, i.e. when the predawn turgor pressure reached zero.
The leaves most reduced in final size when water was withheld were those at the insertions which grew the most rapidly in unstressed plants. The maximum reduction in final leaf size of 25–35% was similar in all cultivars and was due to retardation of the rate of leaf expansion: the duration of leaf expansion was actually increased by stress. However, leaves that were initiated during stress, but emerged after rewatering, had final leaf areas at least equal to those in the unstressed plants: in the cultivar Seneca, the final size of leaves of high insertion was significantly greater in stressed than unstressed plants, whereas in the three other cultivars the final leaf sizes were similar in both treatments. All four cultivars examined adjusted osmotically to the same degree, but leaf water potentials in one, Seneca, increased more rapidly after rewatering than in the other three, and this may have contributed to the greater relative leaf size in the leaves of high insertion in this cultivar.     

Phylogeny and the evolution of nesting behaviour in the tribe Ageniellini (Insecta: Hymenoptera: Pompilidae)

The Pompilidae (spider hunting wasps) show a marked diversity in their hunting and reproductive ecology, but difficulties in phylogenetic taxonomy have hindered the elucidation of their evolutionary processes. We present here a review of the hunting and reproductive ecology of the pepsine tribe Ageniellini (including the first prey record for Macromerella), and phylogenetic analyses of this group to reconstruct the evolution of nest‐constructing behaviour. The maximum parsimony and Bayesian inference analyses are based on 45 adult morphological characters, coded for 41 exemplar species, including five out‐group species, representing almost all the genera and subgenera in this tribe. Results supported the following eight clades uniting more than one genus: (1) Cyphononyx + Cryptocheilus + Ageniellini; (2) Ageniellini; (3) Auplopodina, containing Dimorphagenia, Auplopus, Machaerothrix, Phanagenia, Dichragenia, Paragenia, Macromerella, and Macromeris; (4) Phanagenia + Dichragenia + Auplopus artemis + Paragenia + Macromerella + Macromeris; (5) Auplopus artemis + Paragenia + Macromerella + Macromeris; (6) Paragenia + Macromerella + Macromeris; (7) Macromerella + Macromeris; and (8) Ageniella (Lissagenia) + Phanochilus. The monophyly of the genera Auplopus and Ageniella s.l. was not confirmed. The evolution of nesting behaviour was inferred, as burrowing in the soil without using water was ancestral in Ageniellini, and constructing nests by plastering mud obtained by softening soil with water was derived only once at the ancestor of the Auplopodina. The origin of cleptoparasitism was unclear. The origin of communal nesting is also discussed in relation to the evolution of nest‐constructing behaviour. The following new combinations are proposed: Ageniella (Alasagenia) sartoriana (Cresson) comb. nov. , Cyemagenia certator (Nurse) comb. nov. , and Auplopus artemis (Bingham) comb. nov. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 88–117.     

Differential anatomical responses to elevated CO2 in saplings of four hardwood species

To determine whether an elevated carbon dioxide concentration ([CO₂]) can induce changes in the wood structure and stem radial growth in forest trees, we investigated the anatomical features of conduit cells and cambial activity in 4‐year‐old saplings of four deciduous broadleaved tree species – two ring‐porous (Quercus mongolica and Kalopanax septemlobus) and two diffuse‐porous species (Betula maximowicziana and Acer mono) – grown for three growing seasons in a free‐air CO₂ enrichment system. Elevated [CO₂] had no effects on vessels, growth and physiological traits of Q. mongolica, whereas tree height, photosynthesis and vessel area tended to increase in K. septemlobus. No effects of [CO₂] on growth, physiological traits and vessels were seen in the two diffuse‐porous woods. Elevated [CO₂] increased larger vessels in all species, except B. maximowicziana and number of cambial cells in two ring‐porous species. Our results showed that the vessel anatomy and radial stem growth of Q. mongolica, B. maximowicziana and A. mono were not affected by elevated [CO₂], although vessel size frequency and cambial activity in Q. mongolica were altered. In contrast, changes in vessel anatomy and cambial activity were induced by elevated [CO₂] in K. septemlobus. The different responses to elevated [CO₂] suggest that the sensitivity of forest trees to CO₂ is species dependent.     

Historical divergence of mechanical isolation agents in the ground beetle Carabus arrowianus as revealed by phylogeographical analyses

In the carabid genus Carabus subgenus Ohomopterus , diverged body size and genital morphology serve as mechanical reproductive barriers. To elucidate the diverging process of body and genital sizes in Carabus arrowianus , which exhibits marked morphological diversity among geographical populations and may represent an early stage of speciation, we analysed a mitochondrial gene sequence for 1051 individuals from 63 populations and male morphology for 359 individuals from 47 populations. Two discrete morphological groups segregated by geographical barriers were distinguished, one of which possessed smaller bodies and shorter genitalia ( S group) than the other ( L group), which exhibited larger bodies and exaggerated genitalia. Genetic divergence between the two groups was significant but not large. Phylogeographical and population genetic analyses indicated that the L group was derived from the S group, and a coalescent simulation revealed that the two groups diverged during the latest middle Pleistocene (0.13 million years ago), with a much larger effective population size in the L group than the S group. Because the body size divergence could not be explained by adaptation to climatic conditions and genital morphology is considered to be subject to sexual selection, we postulated that a population division and colonization in favourable habitats caused by the Pleistocene climatic and geographical change might facilitate natural and sexual selection for enlarged body and genital sizes in the L group.     

Morphological,genetic and behavioural analyses of a hybrid zone between the ground beetles Carabus lewisianus and C. albrechti (Coleoptera,Carabidae): asymmetrical introgression caused by movement of the zone?

We analysed the putative hybrid zone between the ground beetles Carabus lewisianus Breuning and C. albrechti Morawitz from the Kanto and Tanzawa Mountains in central Honshu, Japan, using morphological, genetic, and behavioural data. Canonical discriminant analysis of three external and five genital morphological characters revealed an apparent morphological gap, suggesting restricted sympatry in the contact zone. RFLP and molecular phylogenetic analyses of the mitochondrial gene ND5 revealed that haplotypes originating from C. lewisianus introgressed extensively into C. albrechti . Fitting tanh curves to morphological (external and genital) and genetic characters showed differential cline widths and centres, suggesting stronger selection for genital morphology with narrower cline widths, and extensive introgression of the nuclear genes responsible for external characters relative to those controlling genital morphology into the range of C. albrechti . Linkage disequilibria between the morphological characters did not differ from zero, suggesting sufficient recombination occurred in the zone but the effect of small sample sizes was not negligible. Mate choice trials demonstrated that males showed a weak but not significant preference for conspecific mates. We interpret these patterns as evidence for (1) partial reproductive isolation presumably by postmating processes; (2) selection against intermediate genital morphologies, and (3) independent responses of the characters to different evolutionary forces that may cause movement of genital clines and introgression of the mitochondrial gene and external morphology. The movement of the boundaries may have resulted in the particular species distribution patterns in the study area.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 86 , 79–94.     

Local climate mediates spatial and temporal variation in carabid beetle communities in three forests in Mount Odaesan,Korea

1. Global environmental change can dramatically alter the composition of floral and faunal communities, and elucidating the mechanisms underlying this process is important for predicting its outcomes. Studies on global climate change have mostly focused on statistical summaries within wide spatial and temporal scales; less attention has been paid to variability in microclimates at narrower spatial and temporal scales. 2. The microclimate is the suite of climatic conditions measured in a local area. Environmental variables at the microclimatic scale can be critical for the ecology of organisms inhabiting each area. The effect of spatial and temporal changes in the microclimate on the ecology of carabid beetle communities in three sites on Mount Odaesan, Korea was examined. 3. Carabid beetle communities and quantified site‐specific environmental factors from measurements of air temperature, air humidity, light intensity and soil temperature over 5 years (2010–2015) were surveyed. 4. It was found that microclimatic variables and the patterns of temporal changes in carabid beetle communities differed between the three sites within the single mountain system. Microclimatic variables influencing temporal changes in beetle communities also differed between the sites. Therefore, it is suggested that variation in local microclimates affects spatial and temporal variation in carabid beetle communities at a local scale. 5. The present results demonstrate the importance of regular surveys of communities at local scales. Such surveys are expected to reveal an additional fraction of variation in communities and underlying processes that have been overlooked in studies of global community patterns and change.     

Inhibition of female mating by male accessory gland substances in the ground beetle Leptocarabus procerulus

The ground beetle Leptocarabus procerulus (Chaudoir) possesses seminal substances that have a physical function to form mating plugs and a physiological function to induce female refractory behaviour, which act together to hinder female remating. Little is known about the physiological properties of the substances inducing female refractory behaviour, especially with respect to their secretory organ, dose‐dependency, molecular characteristics and the effect of female maturity. By injecting male‐derived substances into females, substances that induce female refractory behaviour are shown to be produced in the male accessory gland but not in the testis. Injection of extracts from the accessory gland increases the female refractory period at moderate doses but not at lower or higher doses. By contrast, injection of extracts from the testis reduces the female refractory period at high doses. The lack of an effect of accessory gland substances at higher doses could be the result of an anomalous effect of unnaturally large doses of seminal products by direct injection, the toxicity of seminal substances that deter female responses, or counteraction by injected substances that promote female receptivity. The accessory gland substances lose their activity when heated, although the testis substances do not. Females without mature eggs tend to reject mating entirely, although variation in the number of mature eggs (one or more) is not associated with the female refractory period, indicating the limited effect of female reproductive maturity. These findings may help to clarify the physiological basis of the evolution of the elaborated male mating behaviour in L. procerulus.     

Dynamics of Insulin Action on Mammary Epithelium

WE have found that, without entering its target cells, insulin elicits biological effects by impinging on the cell membrane. Furthermore, prolonged contact between hormone and mammary cell membrane is not necessary; transient contact through collisions suffices to produce a biological response.