Does rotan <Emphasis Type="Italic">Perccottus glenii</Emphasis> (Perciformes: Odontobutidae) eat the eggs of fish and amphibians?

The introduced fish rotan Perccottus glenii negatively affects the native ecosystems. An integrated study was performed to verify the suggestion that P. glenii feeds on eggs of fish (Rutilus rutilus, Abramis brama, Perca fluviatilis) and amphibians (Rana temporaria, R. arvalis, Bufo bufo). It was found that, during the intraoral testing of fish eggs, P. glenii perceives it as an edible item and swallows; however, under experimental conditions, this predator is limited in its ability for finding this prey because of its immobility. At the last stages of development, the movements of embryos within eggs attract the attention of P. glenii. This increases the vulnerability of fish eggs. In a large water body, there may be a spatial biotopic separation of the sites of egg deposition of some fish (for instance, perch) and the sites of concentrations of P. glenii. This makes eggs inaccessible for this predator. The amphibian eggs, on the contrary, are rejected by P. glenii after intraoral testing, which is determined by the presence of a thick jelly coat. During the period of development of eggs of frogs and toad in a pond, P. glenii actively feed (diverse invertebrates and adult newts were found in their diet); however, they ignore amphibian eggs that successfully develop in water bodies inhabited by P. glenii.     

Sulphur metabolism in Thiorhodaceae. III. Storage and turnover of thiosulphate sulphur inThiocapsa floridana andChromatium species

Thiocapsa floridana strain 1711 andChromatium strains 1211 and 1611 utilize sulphide, thiosulphate, and elementary sulphur as electron donors for growth; sulphite can be used only byChromatium strain 1611. In contrast to the other strains, thiosulphate utilization inChromatium strain 1211 is inducible and not constitutive: thiosulphate is consumed only after an induction period of about 20 hours. The turnover rate of different sulphur compounds is controlled by the CO₂ fixation rate. Using differently labeled³⁵S thiosulphates in short term experiments in a special stirred cuvette, it was shown that the maximum amount of stored intracellular sulphur depends on the strain as well as on the experimental conditions like pH and thiosulphate concentration. WhileChromatium strain 1211 showed a maximum storage of only 10% from sulphane-labeled thiosulphate at pH 6.7, and of 25.7% at pH 6.2,Thiocapsa floridana accumulated 75–90% of the radioactivity into the cells at pH 6.7. While in theChromatium strains the labeling of the cells remained at a constant level until all thiosulphate was consumed, inThiocapsa floridana a defined peak of radioactivity storage was obtained, followed by a steady but 3–4 times slower rate of excretion. With sulphonelabeled thiosulphate no significant accumulation of radioactivity occurred in the cells. During dark-incubation ofThiocapsa floridana (free of intracellular sulphur) in phosphate buffer, pH 6.5, with thiosulphate a production of sulphide could be measured while sulphite was not detected; no sulphide was produced by disrupted cells under the same conditions. The results obtained withThiocapsa floridana strongly support the concept of an initial cleavage of thiosulphate. The present observations do not allow a decision concerning the enzymatic mechanism of the cleavage itself.     

Different thermal stimuli initiate hatching of <Emphasis Type="Italic">Daphnia</Emphasis> diapausing eggs originating from lakes and temporary waters

The simultaneous hatching of Daphnia resting eggs from a number of different lakes and ponds using one set of hatching cues can be difficult to achieve as environmental conditions differ considerably between water bodies. Therefore, optimal hatching conditions for ephippial eggs originating from shallow temporary waters may differ from those found in large lakes. The aim of our study was to compare the optimal thermal conditions for hatching ephippial eggs of Daphnia found in permanent lakes and those from shallow temporary ponds. We used ephippial eggs of Daphnia from the longispina species complex originating from two temporary city ponds and two deep lakes in Poland. The ephippia were protected against overheating at all stages of the field and laboratory work to prevent activation or killing of the eggs. After a refractory period (imposed storage in cool and dark conditions), ephippia were incubated at six different temperatures (6, 9, 12, 15, 18 and 21 °C) under a 16:8 L:D light regime. Our results indicate that hatching of resting eggs of Daphnia that inhabit lakes or ponds may require different thermal conditions. The hatching success of ephippial eggs originating from temporary waters was relatively high (30–56%) at all tested incubation temperatures, while for the ephippial eggs from the deep lakes it was lower (7–37%) and inversely related to water temperature. The divergent hatching responses of the ephippial eggs originating from temporary pools and lakes may reflect the typical thermal conditions during hatching in their native habitats. While in the deep lakes of the temperate zone Daphnia hatching typically occurs during the low water temperatures of early spring, in shallow ponds Daphnia hatching may occur throughout the year at varying water temperatures, from a few to over a dozen degrees Celsius.     

Chemical defences of native European coccinellid eggs against intraguild predation by the invasive Asian coccinellid, <Emphasis Type="Italic">Harmonia axyridis</Emphasis> (Pallas)

Harmonia axyridis (Pallas) is a coccinellid of Asian origin that has recently invaded substantial parts of Europe and is suspected to affect native coccinellid populations through intraguild predation and competition for food. Previous work has shown that two species from the Calvia genus appeared to be well protected against H. axyridis predation. To deepen our understanding on chemical protection of Calvia spp. and the predation risk by H. axyridis, we tested for susceptibility and palatability of Calvia spp. and H. axyridis eggs against predation by H. axyridis neonate larvae. Results show that eggs of C. quatuordecimguttata were mostly not eaten by H. axyridis, while eggs of the congeneric C. decemguttata were found to be largely unprotected against predation by the invasive coccinellid. We also observed that H. axyridis first instars successfully cannibalized on conspecific eggs. Removing the surface chemicals from C. quatuordecimguttata eggs resulted in significantly reduced protection from being preyed upon by H. axyridis, while applying these extracts onto C. decemguttata and H. axyridis eggs resulted in increased protection against H. axyridis larvae. The importance of surface chemicals in the interactions between H. axyridis and native coccinellids was confirmed by GC–MS analysis, showing a high diversity of hydrocarbons located on the surface of C. quatuordecimguttata eggs, i.e. more than twice as many when compared to C. decemguttata. Survival of H. axyridis larvae feeding on eggs of C. quatuordecimguttata, C. decemguttata or conspecific eggs, from which surface chemicals were removed by washing them with hexane, was not different from survival on unwashed eggs.     

Plant and supplementary food sources effect the development of <Emphasis Type="Italic">Dicyphus errans</Emphasis> (Hemiptera: Miridae)

Dicyphus errans (Wolff) (Hemiptera: Miridae) is an omnivorous predator of several pests attacking tomato and other vegetable crops. The nymphal development of D. errans was studied in the presence of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs with or without a water source and in the presence of a leaf of cucumber, eggplant or tomato supplemented with variable food types (E. kuehniella eggs, Artemia sp. cysts, pollen or milk powder) or without the provision of any food. Water provision was found to be essential for the completion of nymphal development even when animal food was offered to predators. When nymphs foraged on leaves in the absence of any food type, development was significantly more favoured on eggplant and cucumber than on tomato. E. kuehniella eggs and Artemia sp. cysts enhanced development of D. errans in comparison to milk powder and pollen. Development and female weight were improved when the food types were offered to the nymphs on a plant leaf than when were provided together with only water. This study contributes to understanding the importance of water vs. plant feeding for the development of D. errans and reveals implications for its mass rearing and application in biological control.     

Meiotic chromosome configurations in oocytes of <Emphasis Type="Italic">Cobitis taenia</Emphasis> and its polyploid hybrids

Diploid and triploid hybrid females of Cobitis as a rule produce unreduced eggs which mainly develop gynogenetically, but some of the eggs incorporate sperm genome and develop into triploids and tetraploids, respectively. Here, we observed for the first time the meiotic chromosomes in the germinal vesicles (GVs) of mature oocytes of three diploid C. taenia (2n = 48) and 20 allopolyploid females of Cobitis (18 triploid 3n = 74 and 2 tetraploid 4n = 99). The majority of GVs in diploid, triploid and tetraploid females contained 24, 74 and 96 or 99 bivalents, respectively. These results directly indicated premeiotic endomitosis as a mechanism underlying the formation of unreduced eggs in allopolyploid females of Cobitis.     

Function and structure of leaves contributing to increasing water storage with height in the tallest <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> trees of Japan

Key message

In Cryptomeria japonica , transfusion tissue in leaves may have functions of water storage and supply, which could compensate for hydraulic constraints with increasing height.

Abstract

The tallest trees of Cryptomeria japonica occur in climatic regions similar to the world’s tallest trees. We hypothesized that tall C. japonica trees would have evolved adaptive mechanisms to overcome height growth limitation. Here, we focused on foliar water storage, a mechanism recently discovered in Sequoia sempervirens. In C. japonica, leaf water potential at turgor loss did not change with height or light availability, while leaf hydraulic capacitance and succulence (water content per leaf surface area) increased, suggesting hydraulic compensation. Plasticity of leaf morphology could contribute to avoiding negative effects of height on photosynthesis. We also focused on the structure and function of transfusion tissue in leaves and its role in water storage and supply. Cross-sectional area of transfusion tissue increased with height, whereas that of xylem was constant. We confirmed that water flowed from vascular bundle to mesophyll via the transfusion tissue. Cryo-scanning electron microscopy images of leaf cross sections showed that transfusion cells were flattened, but not fully dehydrated when leaf water potential decreased in situ and by experimental dehydration, and cell deformation was more marked for treetop leaves than for lower-crown leaves. The shape of transfusion cells recovered at predawn as well as after experimental rehydration. As in S. sempervirens, transfusion tissue of C. japonica may function as a hydraulic buffer, absorbing and releasing water according to leaf water status. Anatomical and hydraulic properties contributing to foliar water storage may be an adaptive mechanism acquired by tall Cupressaceae trees to overcome the hydraulic constraints on physiological function with increasing height.

     

A comparison of partial dehydration and hydrated storage-induced changes in viability,reactive oxygen species production,and glutathione metabolism in two contrasting recalcitrant-seeded species

This study compared the responses of Avicennia marina and Trichilia dregeana seeds, both of which are recalcitrant, to partial dehydration and storage. Seeds of A. marina exhibited a faster rate of water and viability loss (± 50% viability loss in 4 days) during partial dehydration, compared with T. dregeana (± 50% viability loss in 14 days). In A. marina embryonic axes, reactive oxygen species (ROS) production peaked on 4 days of dehydration and was accompanied by an increase in the GSH:GSSG ratio; it appears that the glutathione system alone could not overcome dehydration-induced oxidative stress in this species. In A. marina, ROS and axis water content levels increased during hydrated storage and were accompanied by a decline in the GSH:GSSG ratio and rapid viability loss. In T. dregeana embryonic axes, ROS production (particularly hydrogen peroxide) initially increased and thereafter decreased during both partial dehydration and hydrated storage. Unlike in A. marina embryonic axes, this reduced ROS production was accompanied by a decline in the GSH:GSSG ratio. While T. dregeana seeds may have incurred some oxidative stress during storage, a delay in and/or suppression of the ROS-based trigger for germination may account for their significantly longer storage longevity compared with A. marina. Mechanisms of desiccation-induced seed viability loss may differ across recalcitrant-seeded species based on the rate and extent to which they lose water during partial drying and storage. While recalcitrant seed desiccation sensitivity and, by implication, storage longevity are modulated by redox metabolism, the specific ROS and antioxidants that contribute to this control may differ across species.     

Features of reproductive biology in two tropical fish species from the family Scorpaenidae

Composition of the urogenital system, oocyte development, gamete morphology, and features of embryonic development are described in Scorpaenopsis possi and Sebastapistes cyanostigma (Scorpaenidae) from the Nha Trang Bay, the South China Sea (Vietnam). In males of both species, paired spermiducts enter into the anterior dorsal part of the hypertrophied urinary bladder containing mature sperm. The duration of progressive movements of spermatozoa obtained from the testes and urinary bladder is 5–6 and 12–15 min after activation, respectively. Ovulated oocytes possess oval shapes, they are transparent and without oil droplets. The oocytes are embedded into the floating gelatinous matrix. Insemination of the eggs in nature is apparently external. The embryos of S. cyanostigma hatch at a more advanced morphological condition in comparison to the embryos of Sc. possi. The features of reproductive biology are discussed in the context of the evolution of viviparity within the family.     

Life history differences and latitudinal variation in recruitment in two species of arctic-boreal perciform fishes,the fish doctor <Emphasis Type="Italic">Gymnelus viridis</Emphasis> and the Arctic shanny <Emphasis Type="Italic">Stichaeus punctatus</Emphasis>

Growth and recruitment were examined in two arctic-boreal, shallow water marine perciform species: the fish doctor Gymnelus viridis (Zoarcidae) and the Arctic shanny Stichaeus punctatus (Stichaeidae). G. viridis ranges in the Canadian Arctic from northern Hudson Bay to northern Ellesmere Island, whereas S. punctatus has a more southerly range from Nova Scotia coastal waters to northern Hudson Bay. At Nuvuk Islands in northeastern Hudson Bay, where the two species are sympatric in shallow water, they had comparable juvenile growth rates but temporal variation in 0+ recruitment was substantially greater in S. punctatus. This difference may stem from their contrasting early life histories. S. punctatus spawns large numbers of small demersal eggs that hatch into pelagic larvae, whereas G. viridis spawns small numbers of large demersal eggs that hatch directly into demersal juveniles with no pelagic stage, suggesting that recruitment in G. viridis should be less sensitive to yearly variation in the onset of the ice-free period in Hudson Bay and the subsequent pulse of pelagic invertebrate production. Relative to Nuvuk, recruitment variation in G. viridis was found to be greater at Resolute, Cornwallis Island, close to its northern range limit, whereas recruitment variation in S. punctatus was not evident in Newfoundland, closer to its southern range limit.     

Rate of consumption,biological parameters,and population growth capacity of <Emphasis Type="Italic">Orius laevigatus</Emphasis> fed on <Emphasis Type="Italic">Spodoptera exigua</Emphasis>

Orius laevigatus (Fieber) (Hemiptera: Anthocoridae) is already successfully used to control Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) in protected crops. In the present work, the predatory capacity of O. laevigatus on the eggs and larvae of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) as well as the population growth capacity of O. laevigatus fed on eggs of the noctuid were determined. Fourth and 5th instar nymphs had a greater consumption of eggs than younger ones. Females consumed more eggs than males. Only 5th instar nymphs and adults preyed on the neonatal larvae of S. exigua. The intrinsic rate of natural increase did not differ between O. laevigatus fed with S. exigua eggs and those offered eggs of the substitute host Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae). Thus, O. laevigatus is a good candidate for the biological control of S. exigua, a cosmopolitan pest of many crops.     

The effect of lyophilization and storage time on the survival rate and hydrolytic activity of <Emphasis Type="Italic">Trichoderma</Emphasis> strains

The study evaluates the survivability and storage stability of seven Trichoderma strains belonging to the species: T. harzianum (1), T. atroviride (4), and T. virens (2) after the lyophilization of their solid state cultures on wheat straw. Biomass of Trichoderma strains was freeze-dried with and without the addition of maltodextrin. Furthermore, in order to determine the ability of tested Trichoderma strains to preserve selected technological features, the biosynthesis of extracellular hydrolases (cellulases, xylanases, and polygalacturonases) after a 3-month storage of lyophilizates was investigated. Strains of T. atroviride (except TRS40) and T. harzianum TRS85 showed the highest viability after lyophilization process (up to 100%). After 3 months of storage, T. atroviride TRS14 exhibited the highest stability (95.23%); however, the number of active conidia remained at high level of 10⁶–10⁷ cfu/g for all tested T. atroviride strains and T. harzianum TRS85. Interestingly, after a 3-month storage of lyophilized formulations, most of the tested Trichoderma strains exhibited higher cellulolytic and xylanolytic activities compared to the control, i.e., before freeze-drying process. The highest activities of these enzymes exhibited the following: T. atroviride TRS14–2.37 U/g and T. atroviride TRS25–21.47 U/g, respectively, whereas pectinolytic activity was weak for all tested strains, with the highest value of 0.64 U/g registered for T. virens TRS109.     

Dynamic changes of histone H3 lysine 9 following trimethylation in bovine oocytes and pre-implantation embryos

Objectives

We have examined dynamic changes of histone H3 lysine 9 following trimethylation (H3K9me3), the mRNA expression levels of SUV39H1 and SUV39H2 in bovine oocytes and the role in the development of in vitro fertilization (IVF) pre-implantation embryos.

Results

There were strong H3K9me3 signals in germinal vesicle (GV) oocytes but no signals in MII oocytes. H3K9me3 signals were maintained during IVF pre-implantation embryo development. SUV39H1 and SUV39H2 showed significantly higher mRNA expression levels in GV oocytes than MII oocytes (P < 0.01). SUV39H1 showed high mRNA expression level in two-cell embryos, however, SUV39H2 showed high mRNA expression level in four-cell embryos. In other development stage, SUV39H1 and SUV39H2 showed low expression levels.

Conclusion

Bovine IVF pre-implantation embryos maintain strong H3K9me3 signals and SUV39H1 and SUV39H2 are highly expressed at the early development stage of pre-implantation embryos.

     

Is It Possible to Manipulate Scelionidae Wasps’ Preference to a Target Host?

Parasitoid host selection is mainly mediated by chemical cues, which can be adjusted by experience, changing their innate behavior. Therefore, this study evaluated if immature experience (pre-imaginal conditioning) on eggs and volatiles from different host eggs has influence on parasitism and chemotaxic behavior of Telenomus podisi Ashmead and/or Trissolcus basalis Wollaston (Hymenoptera: Scelionidae). Both wasp species were submitted to a multiple-choice parasitism test among Euschistus heros (Fabricius), Piezodorus guildinii (Westwood), and Nezara viridula L. (Hemiptera: Pentatomidae) (Hemiptera: Pentatomidae) egg masses. Eggs from these three stink bugs were equally offered to female parasitoids. After that, adults which emerged from each host were also exposed to parasitism in a multiple-choice test for up to an additional generation. Moreover, in olfactometer “Y,” the behavior of innate and experienced T. podisi females to volatiles from hosts’ egg extracts was tested, to study their learning and memory ability. The original host had influence on T. podisi parasitism; however, T. basalis always parasitized more N. viridula eggs independently of its last rearing host. Innate T. podisi females responded positively to E. heros and P. guildinii egg volatiles, but this behavior was not observed in N. viridula. When T. podisi females were experienced on egg volatiles from a new host, they showed significant learning and memory ability for the specific host volatile for, at least, 24 h. Experienced wasps responded positively to N. viridula and through this result we have evidences about the possibility to manipulate wasp’s preferences to a specific target host.     

Synthesis and Membrane Transport of Serotonin in the Developing Ovarian Follicle of Mouse

Using RT-PCR, we showed the presence of Tph1 mRNA in follicular cells and Tph2 mRNA in oocytes isolated from primary multilayer ovarian follicles of mouse and the absence of Ddc expression, which indicates that serotonin cannot be synthesized in a developing ovarian follicle. The membrane serotonin transporter Sert is expressed in follicular cells and oocytes. Experiments on the cultivation of follicles in vitro confirmed the absence of serotonin synthesis from 5-hydroxytryptophan and the presence of membrane transport activity in the oocyte.     

Ants (Hymenoptera: Formicidae) as potential egg predators of lepidopteran pests of sweet potato, <Emphasis Type="Italic">Ipomoea batatas</Emphasis> (Solanales: Convolvulaceae), in Japan

The sweet potato Ipomoea batatas (L.) Lam., which has extrafloral nectaries, was visited by nine indigenous ant species in south Kyushu, Japan. These ant species were evaluated for their ability to remove the eggs of two lepidopteran species—Aedia leucomelas (Linnaeus) and Spodoptera litura (Fabricius)—through ant-exclusion experiments. The results showed that Tetramorium bicarinatum (Nylander), one of the dominant ant species, is an efficient predator of lepidopteran eggs. This ant species removed A. leucomelas eggs from ant-visited plants in six trials conducted from mid-July to mid-October, with high removal rates (90–100%) occurring from mid-September onward. On ant-excluded plants, only 0–18% of exposed eggs were removed by ants that accidentally invaded the plants. Tetramorium bicarinatum also removed egg masses and the hatchlings of S. litura. The mean percent area of egg-laden leaves eaten by S. litura larvae was lower on ant-visited plants (0.9%) than on ant-excluded plants (57.3%). In contrast, Formica japonica Motschulsky, another dominant ant species, was not observed removing the eggs or larvae of the lepidopteran species. These results show that certain indigenous ant species are efficient as biocontrol agents. Thus, individual ant species need to be investigated for their ability to control insect pests in various crops.     

The Psilostomidae Looss, 1900 (<Emphasis Type="Italic">sensu stricto</Emphasis>) (Digenea: Echinostomatoidea): description of three new genera and a key to the genera of the family

Three new psilostomid genera, Byrdtrema n. g., Longisaccus n. g. and Macracetabulum n. g., each with a single species, are described from ducks, Aix sponsa (L.) and Bucephala albeola (L.) in North America. Byrdtrema n. g. and Macracetabulum n. g. possess a bipartite seminal vesicle and share this character with four psilostomid genera, Grysoma Byrd, Bogitsh & Maples, 1961, Neopsilotrema Kudlai, Pulis, Kostadinova & Tkach, 2016, Psilostomum Looss, 1899 and Psilotornus Byrd & Prestwood, 1969. Byrdtrema n. g. differs from Macracetabulum n. g. in the shape of the body (elongate vs elongate-oval); the position of the ventral sucker (in first third of body vs just pre-equatorial); the shorter forebody; as well as in the smaller size of the eggs in relation to body length. Both new genera differ from (i) Grysoma by the nature of the vitellarium (large, compact follicles with small vitelline cells vs weakly defined follicles with large vitelline cells, respectively) and the smaller size of the eggs in relation to body length; (ii) Psilostomum in the posterior extend of the cirrus-sac in relation to ventral sucker (slightly posterior vs more posterior), the location of the genital pore (at the level of oesophagus vs just postbifurcal), the shorter length of uterine and longer post-testicular fields in relation to body length, and the anterior limits of vitellarium (at the level of ventral sucker vs posterior to ventral sucker); (iii) Psilotornus by the presence of a muscular pharynx (vs absent or rudimentary) and the location of the cirrus-sac (antero-dorsal to ventral sucker or more posterior vs entirely anterior to ventral sucker) and ovary (in hindbody vs in forebody). Byrdtrema n. g. differs from Neopsilotrema in the shape of the body (elongate vs subspherical to elongate-oval) and ventral sucker (elongate-oval vs subspherical to transversely oval), the shorter forebody and smaller eggs in relation to body length. Macracetabulum n. g. differs from Neopsilotrema by the shape of the ventral sucker (elongate-oval vs subspherical to transversely oval), the anterior limits of vitellarium (level of middle of ventral sucker vs level of intestinal bifurcation or anterior testis); and the slightly smaller size of eggs in relation to body length. Among the psilostomid genera, Longisaccus n. g. shows close affinities to Psilochasmus Lühe, 1909 in the presence of the long cirrus-sac and tubular internal seminal vesicle but can be clearly distinguished from the latter by the absence of the retractile tail-like process. In combination with molecular data, the above differences justify the recognition of three new genera. A key to the genera of the Psilostomidae is provided.     

Low Temperature Storage of <Emphasis Type="Italic">Telenomus remus</Emphasis> (Nixon) (Hymenoptera: Platygastridae) and its Factitious Host <Emphasis Type="Italic">Corcyra cephalonica</Emphasis> (Stainton) (Lepidoptera: Pyralidae)

We conducted three bioassays to evaluate the effect of low-temperature storage of eggs (host) and pupae and adults (parasitoid) on the biology and parasitism capacity of the egg parasitoid Telenomus remus (Nixon) (Hymenoptera: Platygastridae). Viable stored Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae) eggs were parasitized to the same degree or even higher than fresh eggs when stored until 14 days at 5°C or until 21 days at 10°C. In contrast, the percentage of parasitized sterilized eggs was equal to the control only when stored for 7 and 14 days. Survival of T. remus pupae declined with storage time at both studied temperatures (5 and 10°C). However, after 7 days of storage, survival of pupae was still 86.3 and 64.9% at 10 and 5°C, respectively. The number of adult male survivors remained similar until the fourth storage day at both 5 and 10°C. In contrast, female survival did not differ until day 8 at 10°C or day 6 at 5°C. Parasitism capacity of stored adults was not altered by storage compared with the control. Therefore, we conclude that the maximal storage time at 10°C is 21 days for viable C. cephalonica eggs and 7 days for T. remus pupae, while parasitoid adults should not be stored for more than 4 days at either 5 or 10°C.     

Role of CLE41 Peptide in the Development of Root Storage Parenchyma in Species of the Genus <Emphasis Type="Italic">Raphanus</Emphasis> L.

CLE peptides (CLAVATA3/ENDOSPERM SURROUNDING REGION) are signal molecules or plant peptide hormones that play an important role in regulation of development of various meristems governing the expression of WOX (WUSCHEL-RELATED HOMEOBOX) genes. In particular, CLE peptides belonging to a small TDIF (Tracheary Element Differentiation Inhibitory Factor) group are responsible for the operation of gene WOX4 controlling the development of cambium and the conducting system. We looked into the role of CLE41 peptide from the TDIF group in the development of storage root in two species of the genus Raphanus: cultivated radish (Raphanus sativus var. radicula Pers.) that is a popular root crop with a storage root and its ancestor wild radish (Raphanus raphanistrum L.) where storage parenchyma of the root is poorly developed. It was shown that overexpression of gene RsCLE41 and plant treatment with exogenous peptide CLE41 influenced the development of cambium and xylem in the roots of R. sativus and R. raphanistrum and affected expression of the genes from different groups. One could say that peptide CLE41 activates expression of the genes whose homologues in arabidopsis play a key role in the maintenance of cambium (RsWOX4, RsWOX14, RsHAM4, and RsCYCD3). In the storage root of radish, peptide CLE41 activates proliferation of cambium cells reducing the amount of one of the xylem’s elements (lignified parenchyma). The obtained results point to an important role of CLE41 in the development of storage root in radish.