The content of the DNA, the RNA and the wet weight and the RNA:DNA and the wet weight:DNA ratio in different tissues during the growth of chickens. 2. Analysis of the kidney, the spleen, the gizzard and the M. pectoralis superficialis]

At chicken of the race "White Leghorn" the content of nuclei in the kidney was highest (14.60 x 10(9)) on the 203rd, in the spleen on the 112th (14.85 x 10(9)), in the gizzard on the 112th (18,24 x 10(9)) and in the M. pectoralis superficialis on the 168th day (36.42 x 10(9)) after hatching. The biggest fresh weight:DNA-ratio was determined in the kidney on the 203rd (285), in the spleen on the 28th (92) and in the gizzard (694) and in the M. pectoralis superficialis (1984) on the 203rd day. The DNA-concentration on the 2nd day after hatching in the kidney was 4,56 +/- 0,36, in the spleen 11.49 +/- 0.84, in the gizzard 1.85 +/- 0.13 and in the M. pectoralis superficialis 2.96 +/- 0.18 mg/g wet weight respectively the RNA:DNA-ratio in these tissues 1.00, 0.88, 1.70 and 0.85. The growth of tissues by the increase of the number of cells (hyperplasia) and of the volume of cells (hypertrophy) is described.     

Variation in seedling hydraulic architecture as a function of species and environment

Northern red oak (Quercus rubra L.) and yellow-poplar (Liriodendron tulipifera L.) were grown for two years in full sunlight (unshaded) or 20% of full sunlight (shaded) under either well-watered or drought conditions. There was a close association between evaporative flux (in situ) and leaf-specific conductivity (LSC) in stem segments of both species. Shaded, drought-stressed seedlings of both species had significantly reduced leaf area, evaporative flux, volume flow rate in xylem, flow velocity, potentially functional xylem area, and LSC than unshaded, well-watered seedlings. Reductions in LSC associated with drought or shade were similar for both species; and within a treatment, both species had similar LSC. Species differed in the manner of LSC adjustment to drought and shade. Reductions in leaf area associated with drought or shade were accompanied primarily by reductions in potentially functional xylem area for L. tulipifera, and by reductions in flow velocity for Q. rubra. These results suggest (1) the existence of a homeostatic balance between evaporative flux and LSC, (2) that species with widely different growth patterns and xylem anatomies may develop similar LSC within the same environment, and (3) a possible hydraulic basis for differences in habitat between ring- and diffuse-porous species.     

Leaf gas exchange characteristics differ among Sonoran Desert riparian tree species

We investigated leaf gas exchange responses to leaf temperature, leaf-to-air vapor pressure deficit (VPD), and predawn and midday shoot water potential (psipd and psimd, respectively) of two native Sonoran Desert riparian tree species, Fremont cottonwood (Populus fremontii S. Wats.) and Goodding willow (Salix gooddingii Ball), and one exotic riparian tree species, saltcedar (Tamarix chinensis Lour. and related species). Measurements were made at two sites over 2 years that differed climatically. Because multiple linear regression models explained less than 29% of the variation in stomatal conductance (gs) and less than 48% of the variation in net photosynthetic rate (Pn) of all species, we used boundary-line analysis to compare gas exchange responses among species. Gas exchange rates were high in all species. The hyperbolic relationship between Pn and gs suggested that initial reductions in gs at high gs did not inhibit Pn. Reductions in gs of cottonwood and willow occurred at psimd values at or below previously reported xylem cavitation thresholds (-1.6 and -1.4 MPa, respectively), indicating tight stomatal regulation of water loss and a narrow cavitation safety margin. In contrast, reductions in gs of saltcedar occurred at psimd values well above the cavitation threshold (-7.0 MPa), but at much lower psimd values than in cottonwood and willow, suggesting a wider cavitation safety margin and less tight regulation of water loss in saltcedar. High VPD had a smaller effect on leaf gas exchange in willow than in cottonwood. In contrast, willow had a less negative psipd threshold for stomatal closure than cottonwood. Compared with cottonwood and willow, leaf gas exchange of saltcedar was more tolerant of high VPD and low psipd. These physiological characteristics of saltcedar explain its widespread success as an invader of riparian ecosystems containing native Fremont cottonwood and Goodding willow in the Sonoran Desert.     

Boxelder water sources and physiology at perennial and ephemeral stream sites in Arizona

To assess the influence of stream water on leaf gas exchange and water potential in different sized boxelder trees (Acer negundo L.), we compared these characteristics in trees growing beside a perennial stream and a nearby ephemeral stream in a montane-riparian forest in northern Arizona. Patterns of tree water use were quantified by stable isotope analysis (delta(18)O). Physiological characteristics were similar for large and small trees. Similarity between sites in predawn and daytime water potentials and xylem delta(18)O indicated that stream water was not a physiologically important water source. Seasonal and site variations in light-saturated net photosynthetic rate were significantly related to leaf-to-air vapor pressure deficit (r = -0.691) and foliar nitrogen concentration (r = 0.388). Although deep water was the dominant water source, surface soil water was utilized following precipitation, especially by small trees. We conclude that net carbon gain and severity of water stress are only weakly coupled to stream water availability.     

Enzyme arrangement of various tissues in swine. 3. Studies of pre- and postnatal activities of various enzymes (ATPase, GOT, GPT, leucine aminopeptidase, acid and alkaline phosphatases, aldose reductase, glucuronate reductase, sorbitol dehydrogenase) in various tissues]

The crude protein levels as well as the activities of various enzymes were studied in certain tissues of fetuses (80th through 114th days of development), piglets of different age groups, and pigs for slaughter. In most of the tissues tested the postnatal activities of Na-K-ATPase were beyond those recorded from fetuses. The highest GOT activities were recorded from the liver, myocardium, and kidneys. Activities were found to rise sizeably in some tissues after birth. The activity of GPT, too, exhibited age-dependent variations. The activity of leucine-aminopeptidase increased strongly after birth in liver and kidneys. Acid phosphatase activity was less markedly influenced by development phases. Those enzymes which are involved in the formation of fructose and glucose (aldolreductase, glucuronate-reductase, and sorbite-dehydrogenase) had their highest activities, all age-dependent, in liver and kidneys.     

The concentration of ascorbic acid in different tissues of calf fetuses in 3 different development stages]

The concentration of ascorbic acid in the cerebrum and in the brain stem of bovine fetuses decreased with increasing body weight; in the cerebellum there was no change. The decrease of the concentration in the lungs, in the heart, in the kidneys, in the M. longissimus and in the M. semimembranosus in the course of the fetal growth was different. In the liver and in the adrenals the concentration in the 3 groups of fetuses with a body weight of 4.18 +/- 2.01, of 9.72 +/- 0.97 and of 17.12 +/- 2.61 kg was similar. The highest concentrations were found in the adrenals, in the testes and in the cerebrum. The functional significance of the changes in the concentration in the tissues of the bovine fetuses is discussed and compared with the results in human fetuses and in adult cattle.     

Activity and properties of alkaline phosphatase in the plasma and various organs (kidney, liver, small intestine mucosa, bone) of the swine]

There was a high activity of alkaline phosphatase in the blood plasma of piglets during the first few days of live; enzyme obtained at this time had high heat stability and was readily inhibited by L-phenylalanine (5 mM). The enzyme in blood was inhibited to a greater extent than alkaline phosphatase from intestinal mucosa. With increasing age there was a fall in heat stability and in the ease with that the enzyme could be inhibited by phenylalanine. The proportion of alkaline phosphatase derived from bone and present in blood plasma increased with increasing age. Two isoenzymes were detected in liver, kidney, lung, intestinal mucosa and endometrial mucosa by electrophoresis in polyacrylamide gel. Heat lability and inhibition by phenylalanine were good criteria for differentiating different types of alkaline phosphatase in pigs. In the case of alkaline phosphatase in blood plasma, disodium phenylphosphate was split more readily than p-nitrophenyl phosphate and very much more readily than phenolphthalein diphosphate and beta-glycerophosphate.