Host plant variation in mortality of the leaf-folding sawfly on the arroyo willow

Abstract. 1. We tested the hypothesis that survival and sources of mortality of the leaf-folding sawfly ( Phyllocolpa sp.) varied significantly among host plants of the arroyo willow ( Salix lasiolepis Bent ham).
2. Survival of the leaf folder differed among field and potted willows in a common environment in two of three cases, and sources of mortality differed among plants in four of five cases.
3. Egg mortality differed among field plants but not among the potted willow plants.
4. Larval mortality and parasitism differed among field and potted willows in 2 years, and appeared to be compensatory mortality sources.
5. Leaf folder density among plants was not generally correlated with percentage of leaf folds with no egg (galls formed but no subsequent oviposition), percentage survival, or percentage mortality, indicating a general lack of density dependence.
6. The proportion of folds with no egg oviposited differed significantly among field and potted plants, and was only correlated with survival or sources of mortality in one of three years.
7. The data support the hypothesis that host plant genotype affects the interaction of the leaf folder with its natural enemies, and thus represents a three trophic level interaction.     

Transfilter analysis of the inductive influence of proventricular mesenchyme on stomach epithelial differentiation of chick embryos

Summary To clarify the precise conditions under which chick embryonic proventricular mesenchyme can induce proventricular epithelial differentiation, transfilter experiments were carried out. Six-day proventricular epithelium formed glands and expressed pepsinogen when a Nucleopore filter with a pore size of more than 0.6 m, but not 0.2 m, was inserted between the epithelium and the proventricular mesenchyme. The larger the pore size of the filter, the more elongated the glands and the more pepsinogen was induced in the explants. The quail nuclear marker and scanning electron microscopy were used to examine penetration of mesenchymal cells through the Nuclepore filter. The filter of more than 0.2 m pore size allowed cell processes of mesenchymal cells to pass through. However, only the filter with a pore size of more than 0.6 m allowed actual migration of mesenchymal cells through the filter, and the larger the pore size of the filter, the more mesenchymal cells passed through. Under the same conditions 6-day and 4.5-day gizzard epithelium formed glands and expressed pepsinogen. These results indicate that a flow of diffusible substances through a Nuclepore filter and even direct contact of a few short cell processes of mesenchymal cells with epithelial cells are not sufficient for induction, and that direct contact of mesenchymal cell processes and/or mesenchymal cells with epithelial cells over a considerably wide area may be prerequisite for the induction.     

Effects of selection criteria on yield stability in chickpea (Cicer arietinum L.)

Summary Selection in the F₃ generation for seed yield, fruiting branches/plant, effective pods/plant, and seed index (100-seed weight) was carried out in two chickpea crosses. Sixty F₅ lines (15 lines/selection criterion) along with check variety were evaluated for seed yield in three distinct environments. The effects of selection criteria on yield stability was examined using linear regression approach and genotype-grouping technique. There were no differences between selection criteria for linear yield responses of F₅ lines to different environments. Within all four selection criteria the lines showed similar linear responses. The non-linear component was relatively higher for lines selected for effective pods and seed index than lines selected for yield and fruiting branches. On the basis of mean yield and coefficient of variation across environments, the seed index was the least effective selection criterion for developing high yielding and stable lines. When the results of stability parameters and genotype-grouping technique were considered together, selection for yield and fruiting branches was highly effective for isolating stable and high yielding lines.     

Linear and non-linear regression analysis of genotype X environment interactions in pearl millet

Summary Regression analysis was computed on the grain yield of 15 single cross F₁ hybrids of pearl millet (Pennisetum typhoides (Burm.) S. & H.) evaluated in 20 environments at 19 sites in India to assess the nature of genotype X environment interactions. Linear, quadratic, cubic, twoand three-intersecting straight line models were examined for fit. The interactions of six hybrids viz. MH 110, MH 113, MH 114, MH 115, MH 120 and MBH 110 were explained by the linear regression model. The response of the remaining nine hybrids was largely non-linear. The two and three-intersecting straight line models fit better than the quadratic and cubic models and explained non-linearity of response. The two-intersecting straight line models fit for 6 hybrids MH 106, MH 107, MH 112, MH 116, MH 117 and BJ 104. The response of MH 109 was best explained by a three-intersecting straight line model, but there still existed a significant remainder variation. The truncation of environmental range by assuming moving division points was more efficient than the fixed division points for the segmental regression models. The stability of hybrid varieties on the best fitting model has been discussed.     

Studies on the role of iron in the reversal of cadmium toxicity in chicks

Studies were conducted to determine the effect of dietary iron (Fe) levels ranging from a deficiency to an excess on the toxicity of cadmium (Cd) in chicks. In Fe-deficient animals, cadmium was found to be more toxic than in Fe supplemented animals as measured by growth. The liver Cd burdens were increased significantly in the presence of dietary Fe supplementation, and there was a significant Cd−Fe interaction in the Cd concentration of the kidney, indicating that iron deficiency increased the concentration of Cd in the kidneys of those chicks receiving this element. Cd tended to reduce the Fe concentration in both the liver and kidney. The absorption of Cd as measured by the amount of¹⁰⁹Cd that disappeared from an isolated duodenal segment in one h was not affected by the Fe content of the diet, but the amount of isotope appearing in the liver compared to the amount present in the blood was increased in the Fe supplemented chicks. Separation of the Cd binding ligands by column chromatography revealed that more of the Cd in the liver, but not the kidney, was associated with ligands which eluted in a column volume that contained metallothionein in those chicks receiving Fe than in the livers from Fe deficient animals. The inverse relationship between the amount of Cd bound to the metallothionein containing fraction and toxicity may be related causally. Paper No. 10538 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, NC 27695-7601. The use of trade names in this publication does not imply endorsement by the NC Agricultural Research Service of the products named nor criticism of similar ones not mentioned.     

Variation in host susceptibility among and within populations ofPlantago lanceolata L. infected by the fungusPhomopsis subordinaria (Desm.) Trav.

Summary Susceptibility toPhomopsis stalk disease ofPlantago lanceolata genotypes, sampled in three different populations with a variable degree of infection by the fungusPhomopsis subordinaria, was determined under greenhouse conditions. Susceptibility of the host varied within, but not among populations. No relationship between the intensity of the disease in the field and the mean susceptibility of the host genotypes sampled at those locations could be established. Host susceptibility appeared to be composed of the host genotypes sampled at those locations could be established. Host susceptibility appeared to be composed of different (uncorrelated) plant characteristics. Determining whether host genotypes are highly or slightly susceptible can only be achieved by field trials, where the plants are exposed to the whole set of disease inducing factors. The relevance of host susceptibility to the intensity of disease in the field is discussed in relation to the variation in pathogenicity of the fungus and the variation in environmental factors prevailing inP. lanceolata populations underP. subordinaria pathogen pressure. Grassland Species Research Group Number 123     

Cytoplasmic free calcium in Riccia fluitans L. and Zea mays L.: Interaction of Ca2+ and pH?

In cells of Zea mays (root hairs, coleoptiles) and Riccia fluitans (rhizoids, thalli) intracellular Ca²⁺ and pH have been measured with double-barrelled microelectrodes. Free Ca²⁺ activities of 109–187 nM (Riccia rhizoids), 94–160 nM (Riccia thalli), 145–231 nM (Zea root hairs), 84–143 nM (Zea coleoptiles) were found, and therefore identified as cytoplasmic. In a few cases (Riccia rhizoids), free Ca²⁺ was in the lower millimolar range (2.3±0.8 mM). A change in external Ca²⁺ from 0.1 to 10 mM caused an initial and short transient increase in cytoplasmic free Ca²⁺ which finally levelled off at about 0.2 pCa unit below the control, whereas in the presence of cyanide the Ca²⁺ activity returned to the control level. It is suggested that this behaviour is indicative of active cellular Ca²⁺ regulation, and since it is energy-dependent, may involve a Ca²⁺-ATPase. Acidification of the cytoplasmic pH and alkalinization of the vacuolar pH lead to a simultaneous increase in cytoplasmic free Ca²⁺, while alkalinization of pH_c decreased the Ca²⁺ activity. Since this is true for such remote organisms as Riccia and Zea, it may be concluded that regulation of cytoplasmic pH and free Ca²⁺ are interrelated. It is further concluded that double-barrelled microelectrodes are useful tools for investigations of intracellular ion activities in plant cells.Symbols and abbreviations _m, _m membrane potential difference, changes thereof - PVC polyvinylchloride     

大叶杨组组间杂交花粉－柱头相互作用的超微结构研究

以大叶杨为母本,分别与小叶杨、欧洲黑杨、响叶杨进行人工杂交,并以大叶杨×大叶杨为对照,观察其花粉与柱头相互作用的超微结构变化。结果表明,大叶杨柱头细胞在授粉前表现生理活跃,含丰富的细胞器,壁外被含分支通道的角质层。接受大叶杨及欧洲黑杨花粉的柱头细胞内部仍有丰富的细胞器,膜结构保存完好。接受小叶杨及响叶杨花粉的柱头细胞衰亡较快,授粉部位沉积厚的胼胝质,细胞内部液泡化,膜结构逐渐消失,细胞质电子密度加大。欧洲黑杨花粉行为与大叶杨花粉行为相似,花粉能迅速萌发,并以短管形式穿入柱头,异常行为罕见。小叶杨及响叶杨花粉萌发后只有半数花粉管能以短管形式进入柱头,其中部分管内沉积胼胝质,另半数花粉管在柱头上表现各种异常行为——扭曲、爬行、肿胀、提前破裂释放内容物及先端沉积胼胝质。由各种花粉在大叶杨柱头上的行为和大叶杨柱头对各种授粉的反应判断,与大叶杨杂交亲和力在柱头阶段表现由强至弱依次是欧洲黑杨、小叶杨、响叶杨。     

The structure and cytochemistry of the pistil of Hypericum calycinum: the style

Summary A typical style of Hypericum calycinum is solid with a core of transmitting tissue traversing the whole length of the style. This transmitting tissue consists of loosely arranged cells and large intercellular spaces filled with a secretion product. The secretion product is rich in lipids, but poor in proteins and polysaccharides. The intercellular spaces of the transmitting tissue originate partly by a separation of cells as a result of the decomposition of the middle lamella and partly by degeneration of some of the cells of the transmitting tissue. H. calycinum is self-compatible. Both self- and cross-pollinations result in profuse pollen germination on the stigma and pollen tube growth through the style. The data on Hypericum is discussed in relation to information available on other solidstyled systems.     

Interaction of opioid peptides and other drugs with multiple delta ncx binding sites in rat brain: further evidence for heterogeneity.

Recent pharmacological data strongly support the hypothesis of δ receptor subtypes as mediators of both supraspinal and spinal antinociception (δ₁ and δ₂ receptors). In vitro ligand binding data, which are fully supportive of the in vivo data, are still lacking. A previous study indicated that [³H][ -Ala², -Leu⁵]enkephalin labels two binding sites in membranes depleted of μ binding sites by pretreatment with the site-directed acylating agent, 2-(p-ethoxybenzyl)-1-diethylaminoethyl-5-isothiocyanatobenzimidazole-HCI (BIT). The main goal of the present study was to develop a ligand-selectivity profile of the two δ_ncx binding sites. The data indicated that naltrindole and oxymorphindole were relatively selective for site 1 (20-fold). [ -Ser²,Thr⁶]Enkephalin and deltorphin-II were only 2.7-fold and 2.2-fold selective for site 1. [ -Pen², -Pen⁵]Enkephalin and deltorphin-I were 80-fold and 38-fold selective for site 2.3-Iodo-Tyr- -Ala-Gly-Phe- -Leu was 52-fold selective for site 1. Morphine had moderate affinity for site 1 (K_i = 16 nM), and was about 11-fold selective for site 1. Thus, of the 10 drugs studied, only DPDPE and DELT-I were selective for site 2. Viewed collectively with other data, it is likely that the δ₁ receptor and the δ_ncx binding site are synonymous.