Water Influx Characteristics and Hydraulic Conductivity for Roots of Agave deserti Engelm.

Various plant and environmental factors influence the hydraulicproperties for roots, which were examined using negative hydrostaticpressures applied to the proximal ends of individual excisedroots of a common succulent perennial from the Sonoran Desert,Agave deserti Engelm. The root hydraulic conductivity, L^p, increasedsubstantially with temperature, the approximately 4-fold increasefrom 0.5°C to 40°C representing a Q¹⁰ of 1.45. Suchvariations in L_p with temperature must be taken into accountwhen modelling water uptake, as soil temperatures in the rootzone of such a shallow-rooted species vary substantially bothdaily and seasonally. At 20°C, L_p was 2.3 x 10^–7 ms^{macron}1MPa^{macron}1for 3-week-old roots, decreasing to abouthalf this value at 10 weeks and then becoming approximatelyhalved again at 6 months. For a given root age, L_p for rainroots that are induced by watering as lateral branches on theestablished roots (which arise from the stem base) was aboutthe same as L_p for established roots. Hence, the conventionalbelief that rain roots have a higher L_p than do establishedroots is more a reflection of root age, as the rain roots tendto be shed following drought and thus on average are much youngerthan are established roots. Unlike previous measurements onroot respiration, lowering the gas-phase oxygen concentrationfrom 21% to 0% or raising the carbon dioxide concentration from0.1% to 2% had no detectable effect on L_p for rain roots andestablished roots. L_p for rain roots and established roots wasdecreased by an average of 11% and 35% by lowering the soilwater potential from wet conditions (_soil=0 kPa) to {macron}40kPa and {macron}80 kPa, respectively. Such decreases in L_p mayreflect reduced water contact between soil particles and theroot surface and should be taken into account when predictingwater uptake by A. deserti. Key words: Gas phase, rain roots, root age, soil, temperature, water potential     

Influences of Water Status, Temperature, and Root Age on Daily Patterns of Root Respiration for Two Cactus Species

Daily patterns of root respiration measured as CO₂, efflux werestudied at various soil water potentials, temperatures, androot ages for individual, attached roots of the barrel cactusFerocactus acanthodes and the platyopuntia Opuntia ficus-indica.The daily patterns of root respiration for both establishedroots and rain roots followed the daily patterns of root temperature.Root respiration increased when root temperature was raisedfrom 5 °C to 50 °C for F. acanthodes and from 5 °Cto 55 °C for O. ficus-indica; at 60 °C root respirationdecreased 50° from the maximum for F. acanthodes and decreased25° for O. ficus-indica. Root respiration per unit d. wtdecreased with root age for both species, especially for rainroots. Root respiration rates for rain roots were reduced tozero at a soil water potential (     

Ecological and morphological characteristics of endoparasitoids on Elcysma westwoodii (Vollenhoven) (Lepidoptera: Zygaenidae)

Six species of insect endoparasitoids were identified from Elcysma westwoodii, which is the most damaging lepidopteran pest of Prunus yedoensis. From Hymenoptera, two species were identified: a species in Braconidae and Charops striatus in Ichneumonidae. From Diptera, there were four species in Tachinidae: Compsilura concinnata, Exorista sp., Pales sp. and Tachinidae spp. The parasitic ratio was 4.86% (45 of 926 larvae). The hymenopterans were parasitic on 31 individuals of E. westwoodii (68.9%) and the dipterans were parasitic on 14 individuals (31.1%). It was found that parasitoids from the larvae of E. westwoodii were all either endoparasitoids or larval parasitoids. However, Exorista sp. of Tachinidae was found to be either a larval parasitoid or larval-pupal parasitoid. Additionally, all the identified parasitoids were solitary parasitoids, as only one parasite occurred in a larva of E. westwoodii. Because the larva of E. westwoodii eats and molts after it is parasitized, all the parasitoids were identified as koinobionts. There were no big differences in morphological characteristics and life histories between C. striatus and C. concinnata. However, for Exorista sp. and Pales sp., males took 3–5 days longer to emerge from their pupae and had remarkably longer body lengths than females.     

Internal Leaf Area and Cellular CO2 Resistance: Photosynthetic Implications of Variations with Growth Conditions and Plant Species

The influences of illumination, temperature, and soil water potential during development on leaf thickness, mesophyll cell wall area per unit leaf area (^Ames/A), and the cellular CO₂, resistance expressed on a mesophyll cell wall area basis (r_CO2^cell,) were examined for Plectranthus parviflorus Henckel. Although the ranges of all three growth conditions caused at least 9-fold variations in the leaf biomass produced in 4 weeks, only the illumination had a major effect on internal leaf morphology, e.g. the thickness went from 279 to 831 μm and A^mes/A from 10.5 to 34.8 as the photosynthetically active radiation was raised from 3 to 53 nEinsteins cm^?2 s^?1, while r_CO2^cell remained close to 154 s cm^?1. Variations in the growth temperature, soil water potential, and the nutritional status of the plant, affected photosynthesis mainly by changes in r_CO2^cell. To compare the influence of internal leaf area on photosynthesis for other plants, especially those with low A^mes/A values, the maximum rates of CO₂ uptake at light saturation and photosynthetically optimal temperatures were also determined for a moss, Mnium ciliare (C. Muell.) Schimp., and two ferns, Adiantum decorum Moore and Alsophila australe R. Br. As Ames/A went from 2.00 for the moss to 3.8, 7.5, 11.7, and 20.8 for the fens, the illumination at light saturation and the maximum rate of photosynthesis both progressively increased. The cellular CO₂ resistance, which theoretically might have a lower limit of 20 s cm^?1, ranged from 85 to 190 s cm^?1.     

Genus Thubana Walker in Indonesia, with descriptions of four new species (Lepidoptera: Lecithoceridae) and a world catalog of the genus

The genus Thubana Walker (Lepidoptera: Lecithoceridae: Torodorinae) in Indonesia is reviewed, with three known species from Java and four additional new species: Th. raphidodea sp. nov. from Sulawesi, Indonesia and Malaysia; and Th. erycinae sp. nov., Th. apiculalis sp. nov. and Th. sellarius sp. nov. from Sumatra, Indonesia. The previously known species from Java, Th. costimaculella (Snellen), is redescribed for the wing venation and genitalia of both sexes; however, the syntype of Th. heylaertsi (Snellen) is observed only by its photograph. No specimens of Th. heylaertsi and Th. xylogramma Meyrick were found during this study. Photos of all known species, except Th. xylogramma Meyrick, and a key to species are provided. A catalog for the genus with all 46 known species in the world is given.     

Light Microscopic Observations, Ultrastructure, and Molecular Phylogeny of Hicanonectes teleskopos n. g., n. sp., a Deep-Branching Relative of Diplomonads

ABSTRACT. We describe Hicanonectes teleskopos n. g., n. sp., a heterotrophic flagellate isolated from low-oxygen marine sediment. Hicanonectes teleskopos has a ventral groove and two unequal flagella, and rapidly rotates during swimming. At the ultrastructural level H. teleskopos is a "typical excavate": it displays flagellar vanes, a split right microtubular root, "I,""B," and "C" fibres, a singlet microtubular root, and a possible composite fibre. Small subunit rRNA (SSU rRNA) gene phylogenies and an "arched" B fibre demonstrate that H. teleskopos belongs to Fornicata (i.e. diplomonads, retortamonads, and relatives). It forms a clade with the deep-branching fornicate Carpediemonas , with moderate-to-strong bootstrap support, although their SSU rRNA gene sequences are quite dissimilar. Hicanonectes differs from Carpediemonas in cell shape, swimming behaviour, number of basal bodies (i.e. 4 vs. 3), number of flagellar vanes (i.e. 2 vs. 3), anterior root organization, and by having a cytopharynx. Like Carpediemonas and Dysnectes, Hicanonectes has conspicuous mitochondrion-like organelles that lack cristae and superficially resemble the hydrogenosomes of parabasalids, rather than the mitosomes of their closer relatives the diplomonads (e.g. Giardia ).     

Two middle Cambrian diceratocephalid trilobites, Cyclolorenzella convexa and Diceratocephalus cornutus, from Korea: development and functional morphology

Park, T.-Y. & Choi, D.K. 2010: Two middle Cambrian diceratocephalid trilobites, Cyclolorenzella convexa and Diceratocephalus cornutus , from Korea: development and functional morphology. Lethaia , Vol. 43, pp. 73–87.
Silicified sclerites of the latest middle Cambrian trilobites, Cyclolorenzella convexa and Diceratocephalus cornutus , have been recovered from the Sesong Formation, Korea. Their morphological similarity and stratigraphic occurrences suggest that D. cornutus is a descendant of C. convexa . The ontogenies of both trilobites demonstrate that a pair of long frontal horns in the cephalon of D. cornutus is an evolutionarily novel structure. It is inferred that redeployment of some pre-existing regulatory gene played a significant role in constructing the frontal horns of D. cornutus . The frontal horns may have been a defensive structure to deter predators. The facial suture of D. cornutus , which extends onto the frontal horns and splits them into the dorsal and ventral halves, was a solution to enable easier forward egression during ecdysis. □ Functional morphology, Korea, Middle Cambrian, ontogeny, trilobites .