The Geotropic Curvature in Roots of Norway Spruce (Picea abies) Containing Anthocyanins

Seedlings of Norway spruce (Picea abies L.) have been found to synthesize anthocyanins in the root tips as well as in the hypocotyls upon irradiation with white light when kept at 4°C for 6–8 days. In addition, it has also been found that the elongation and the geotropic curvature of spruce roots are dependent on the light conditions. The course of the geotropic curvature in spruce roots containing anthocyanins has been followed during a period of 5 h, in which the seedlings were geotropically stimulated continuously in the horizontal position. When the stimulation was performed in white light and in darkness at 21°C, significantly larger curvatures were observed in the roots pretreated at 4°C in darkness than in the roots containing anthocyanins. The specific curvature (curvature in degrees per mm elongation), however, was approximately the same in both types of roots stimulated in white light. This was due to a retarded elongation of the roots pretreated with light at 4°C and containing anthocyanins. A smaller difference in elongation rate between roots with and without anthocyanins was observed in the dark than in the light, but even in the dark the anthocyanin-containing roots grew more slowly than roots without anthocyanins. In order to find out if it is the anthocyanin content or the illumination which affects the elongation and geotropic curvature in the roots, a series of similar experiments was performed using cress seedlings grown at 4°C in light or darkness. Roots of cress seedlings cultivated under conditions which would induce anthocyanin formation in spruce roots exhibited the highest geotropic responses both in light and darkness as compared to cress seedlings grown at 4°C in darkness. As in the case of spruce roots an increase in elongation was observed in cress roots illuminated during the geotropic stimulation. These similarities in the behaviour made it relevant to compare the development of the geotropic curvature in cress and spruce roots.     

Body size establishes the scaling of avian postnatal metabolic rate: an interspecific analysis using phylogenetically independent contrasts

The avian postnatal metabolic rate literature is reviewed using power equations, Y = aM^b, to describe the relation between postnatal resting metabolic rate (RMR) and chick body mass (M) for 25 species. In altricial species, the relation between RMR and M from hatching to fledging can be described by a single power equation, whereas in most nonaltricial species two such equations are needed, one for chicks weighing less than about 25% of mature mass ( M _a) and a second for larger chicks. For altricial chicks and larger nonaltricial chicks, the body-mass exponent, b, of 25 intraspecific power equations ranged from 0.25 to 1.67 and varied inversely with M _a. The scaling of postnatal RMR is thus unlike that of either adult or hatchling metabolism in that it is size dependent. We examined the relationship between intraspecific b and M _a using Felsenstein's independent contrasts method to control for statistical complications due to the hierarchical nature of phylogenetic relationships. This "phylogenetic regression" technique yielded the relation b = 1.6 M _a^-015, in which mature mass explained 38% of the variation in b. The mass exponent of this equation (-0.15) did not differ significantly from that determined by nonphylogenetic methods (-0.17).
In altricial chicks and larger nonaltricial chicks, the scaling coefficient, a, of the interspecific power equations varied with adult mass according to the phylogenetically determined relation a (kj/h) = 0.0052M_a^0.65and was higher in fed than in fasted chicks. Equations derived in this analysis permit one to estimate the RMR of a growing chick from its mass and adult body mass and provide a basis for evolutionary and ecological comparisons.     

Growth of corn in saline waters

Eight cultivars of Zea mays plus the wild species Zea diploperennis were screened for seedling saline tolerance up to 3.2% NaCl. The best performances were given by the cultivars Mo 17 and commercial Hawaiian Super Sweet Hybrid. These two were then field grown on coral-cinder beds using drip irrigation with fresh of half-strength sea water (1.5–1.7% dissolved solids). Growth and chemical data for Mo 17 at 12 weeks show reduced growth but the same percentage dry matter. Ash, protein and total sulfur were higher in saline plants, silica and total phosphorus lower. Na, K. Mg, and Cl were elevated and Ca reduced slightly. Fe was also increased in saline plants. Both Mo 17 and Super Sweet Hybrid corn flowered and produced seed which retained essentially normal viability both in fresh and salt water.