Induction of tetraploidy in garden cress: morphological and cytological changes

Plant Cell, Tissue and Organ Culture (PCTOC) - Garden cress (Lepidium sativum L., Brassicaceae) is one of the most popular leafy vegetables which is widely used, and has also various medicinal...     

Spatio‐temporal association of Therioaphis maculata and Hippodamia variegata in alfalfa fields

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The effects of dietary Betaplus® and TechnoMos® on growth performance,blood parameters,and intestinal microflora in juvenile kutum,Rutilus kutum (Kamensky, 1901)

The main goal of the current study was to assess the combined effects of a dietary probiotic Betaplus and prebiotic TechnoMos on growth performance, blood biochemical parameters, and intestinal microflora in juvenile Rutilus kutum. Four experimental diets were prepared with the addition of Betaplus and/or TechnoMos to a basal diet for R. kutum juveniles. The diets were randomly assigned to one of 12 tanks, with three replications per diet. The results showed that supplementation of both pro‐ and prebiotic, separately or in combination, improved fish growth parameters (p < .05). These additives also reduced fish mortality rates, either alone or in combination (p < .05). Protein content of the carcass increased by an addition of Betaplus (p < .05), but Betaplus supplementation reduced the fat content of the carcass (p < .05). Bacillus leicheniformis and B. subtilis counts were elevated by the addition of Betaplus and TechnoMos, with even a larger bacterial count observed in fish fed a mixed diet of pro‐ and prebiotics (p < .05). White blood cell counts increased with both pro‐ and prebiotic supplementations. Glucose and cortisol levels significantly decreased with the administration of Betaplus and TechnoMos, and the mixed treatment showed the lowest estimate of these parameters (p < .05). In conclusion, a better performance of juvenile R. kutum fed a diet mixture of Betaplus and TechnoMos is probably related to the elevation of Lactobacillus counts in the fish gut, which improves the digestive performance.     

In vitro polyploidy induction: changes in morphology,podophyllotoxin biosynthesis,and expression of the related genes in Linum album (Linaceae)

Planta - Induction of tetraploidy was performed and podophyllotoxin production increased by upregulating the expression level and enzyme activity of genes related to its biosynthesis in tetraploid...     

Plant Resistance Affects the Olfactory Response and Parasitism Success of Cotesia vestalis

Understanding the factors influencing host-selection behavior of parasitoids is essential in studies on host-parasitoid ecology and evolution, and in combining sustainable strategies of pest management, such as host-plant resistance and biological control. The effects of host-plant resistance on the olfactory response and parasitism success by Cotesia vestalis, a parasitoid of diamondback moth (Plutella xylostella) larvae were examined. Here, it was demonstrated that host-plant resistance can strongly influence foraging behavior and parasitism success of the parasitoid. In olfactometer experiments, C. vestalis did not differentiate between crucifer plant types with similar levels of susceptibility or resistance to P. xylostella but showed a strong preference for susceptible compared with partially-resistant host plants. The influence of previous oviposition activity varied with the host-plant type experienced by the parasitoid. In cage experiments, C. vestalis preferred to parasitize P. xylostella larvae on a susceptible plant compared with larvae on a partially resistant host plant when exposed to hosts for 24 h. However, this preference appeared to be transitory, and was not found after 96 h exposure. The present study suggests that combining partial host-plant resistance with biological control by C. vestalis for the control of P. xylostella may in some circumstances be antagonistic and negatively affect parasitism success.     

Cold-induced accumulation of protein in the leaves of spring and winter barley cultivars

Electrophoretic pattern and quantitative changes in soluble proteins were determined in the leaves of spring and winter cultivars of barley (Hordeum vulgare L., cv. Makouei and cv. Reyhan, respectively) exposed to 4 degrees C for 14 d. Seedlings were grown in a controlled growth chamber for 2 weeks at a constant air temperature of 20 degrees C and then transferred to constant 4 degrees C for 14 d followed by returning to 20 degrees C (cold treatment), or they were maintained throughout at 20 degrees C during the experimental period of 40 d (control treatment). Plants were sampled every 48 h for leaf fresh weight measurements. Total leaf soluble proteins were extracted and their concentration was either determined by a colorimetric method, or size-fractionated on SDS-PAGE. Low temperature-induced increases in protein amount occurred over the second week of exposure to cold treatment irrespective of cultivar: the winter cultivar was 2 d prior in this response. The protein patterns and their density showed differences between-cultivars and between-temperature treatments. A new cold-induced polypeptide was recognized in the leaves of winter barley cultivar on day 22 (8 d at 4 degrees C) compared to the control. This polypeptide was produced earlier over the first 48 h of low temperature in the winter cultivar compared with the spring one, recognizing in the leaves of cold-treated seedling until day 26. This more rapid response to a low temperature by the winter barley cultivar indicates a more sensitive response compared with the spring barley, probably cold-shock protein is a component of this cold-induced response.     

Dynamic economic thresholds for the management of vegetable leafminer on glasshouse cucumber estimated by simulated defoliation

Defoliation by the vegetable leafminer, Liriomyza sativae Blanchard (Diptera: Agromyzidae), was simulated by removing known amounts of leaf area with a hole punch in a glasshouse experiment that evaluated 21 combinations of defoliation intensity, timing and duration on cucumber yields. Defoliation was quantified in cm²-days (leaf area removed x no. days), and linear regression was used to correlate yield losses to simulated damage. The probability of erroneous decisions associated with different intensities of sequential sampling was explored. Spatial heterogeneity in leafminer infestation and the cumulative impact of defoliation over time were both considered, and the economic costs associated with wrong decisions were also assessed. Significant yield loss was observed beyond 10,000 cm²-days of defoliation, whereas lower defoliation levels were tolerated by plants. The economic injury level (EIL) rose at an increasing rate as the onset of defoliation moved later in the season. An algorithm was used to estimate monthly EILs that farmers can use to guide leafminer management decisions in cucumber and minimize their economic risk.     

Spatial and developmental expression of key genes of terpene biosynthesis in Tanacetum parthenium

Feverfew (Tanacetum parthenium) is a medicinal plant belonging to the Asteraceae family. To improve understanding terpene metabolism in feverfew, the relative gene expression of four key genes coding 3-hydroxy-3-methylglutarylcoenzyme A reductase (HMGR) and germacrene A synthase (GAS) from the mevalonic acid pathway (MVA), as well as 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR) and hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate reductase (HDR) from the methyl erythritol phosphate pathway (MEP), were examined. Target organs and tissues included young leaves (not fully expanded), mature leaves (fully expanded), flowers, stems, roots, and glandular trichomes. HMGR, DXR, and HDR were isolated and sequenced for the first time in feverfew. Real-time quantitative PCR analysis revealed differential expression of these genes in feverfew tissues and developmental stages.