Some behavioural observations on wild and captive sand monitors, Varanus gouldii (Sauria: Varanidae)

Behavioural observations were made on wild and captive sand monitors in Australia. Threat and defensive postures are described for V. gouldii and reference is made to V. varius and V. spenceri; such behaviour is compared to other species within the family Varanidae. With captive V. gouldii, one case of cannibalism occurred when space was restricted.     

RNA Species during Visual Stimulation

AS part of a programme concerned with the quality of RNA synthesized during behaviour we have carried out an experiment to detect the synthesis of qualitatively unique species of RNA during visual stimulation. Two litters of male Wistar rats were housed in a dimly lit room from 40 days of age. At 100 days four members of each litter were injected intracran-ially with 1 mCi of 5-³H-uridine and after 30 min were subjected to 90 min of visual stimulation (experimental subjects), while other rats of each litter were restrained in darkness (control subjects).     

A Study of the Growth of Excised Embryo Shoot Apices of Wheat In vitro

A technique for obtaining excised embryo shoot apices of wheatis described. When yeast extract or various amino acids wereincluded in the basal medium the explants did not grow and muchof the tissue showed signs of necrosis. Coconut milk, eitherautoclaved or filter-sterilized, inhibited the growth of theexplants. Root initiation and shoot growth were stimulated byammonium salts. It was not known whether root initiation wasthe result of stimulation by ammonium salts or the rapid growthof the shoot apex. Aqueous extracts of roots also stimulatedthe growth of the explants, but extracts of other plant organsdid not. The addition of individual vitamins had various effectson the growth of the explants, but since the growth responsewas so slow, results other than complete inhibition were rejected.On the basis of these results, other substances appear to benecessary to support the growth of wheat explants without theinitiation of roots.     

Genetic differentiation and diversity of Acacia koa populations in the Hawaiian Islands

Acacia koa A. Gray (koa) is a leguminous tree endemic to the Hawaiian Islands and can be divided into morphologically distinguishable groups of A. koaia Hillebrand, A. koa and populations that are intermediate between these extremes. The objectives of this investigation were to distinguish among divergent groups of koa at molecular levels, and to determine genetic diversity within and among the groups. Phylogenetic analyses using the ITS/5.8S rDNA and trnK intron sequences did not separate the representative koa types into distinct clusters. An unweighted pair group method with arithmetic mean cluster analysis and principal coordinate analysis, based on allele profiles of 12 microsatellite loci for 215 individual koa samples, separated the population into three distinct clusters consistent with their morphology, A. koaia, A. koa and intermediate forms. There was an average of 8.8 alleles per polymorphic locus (AP) among all koa and koaia individuals. The intermediate populations had the highest genetic diversity (H′ = 1.599), AP (7.9) and total number of unique alleles (21), whereas A. koaia and A. koa showed similar levels of genetic diversity (H′ = 0.965 and 0.943, respectively). No correlation was observed between geographic distance and genetic distance as determined by a Mantel test (r = 0.027, P = 0.91). The data presented here support previous recommendations that morphological variation within koa should be recognized at the subspecific level rather than as distinct species.     

Pattern and Control of Distribution of 14C-assimilates in Reproductive Plants of Lolium multiflorum Lam. var. Westerwoldicum

The distribution of ¹⁴C-assimilates was examined in reproductiveplants of Lolium multiflorum Lam. var. Westerwoldicum (cv. Tama)from which all emerged tillers had been removed, leaving themain tiller with two expanding leaves, one of them the flagleaf, and two expanded leaves. Export of ¹⁴C from the lowerexpanded leaf was mainly to the tiller in its axil, the steminternode below its node and the roots, whereas the upper expandedleaf supplied predominantly the expanding leaves, the ear, steminternodes, roots and the tiller bud in the axil of the lowerleaf. Defoliation and root-pruning showed that expanding leaveswere able to compete successfully for assimilates, probablythrough the production of substances capable of mobilizing supply.Local application of 1-naphthaleneacetic acid (NAA), gibberellicacid (GA₃) and 6-benzylaminopurine (BAP) to small tiller budsshowed that GA³ and BAP promoted bud growth and ¹⁴C accumulation,but that addition of NAA reduced these effects.     

Seasonal Altitudinal Movements of Mountain Goats

Abstract: I investigated seasonal altitudinal movements of 42 mountain goats (Oreamnos americanus) in the Cascade Range of Washington, USA. Because mountain goats typically move to lower elevations during the winter, I partitioned locations from Global Positioning System collars into summer and winter seasons based on elevation. Using an iterative narrowing search, I identified summer and winter start dates for each individual and year and derived several measures of altitudinal movements from these, and examined differences in these measures on the basis of sex and year and their interrelationship. Generally, female mountain goats started summer about 2 weeks earlier than nondispersing males; winter start dates varied among years. Horizontal distance moved between seasons was unrelated to measures of altitudinal movement. Based on elevation, winters were generally longer than summers for mountain goats I studied, suggesting that the common perception of mountain goats as inhabitants of alpine and subalpine terrain is biased, because they spent the greater part of the year at lower elevations. Mountain goats showed a wide range of responses to seasonal environmental changes and individuals cannot be easily classified as migratory or nonmigratory. Because ecological conditions in mountain environments are closely related to elevation and horizontal and altitudinal movements were unrelated, studies of seasonal movements of mountain animals based on horizontal movement may be misleading. Because seasonal altitudinal movements of mountain goats are highly variable, the management needs of each population must be considered separately.     

Characterization of Chemical Contamination in Shallow-Water Estuarine Habitats of an Industrialized River. Part 1: Organic Compounds

The lower six miles of the tidal portion of the Passaic River (Study Area) has been heavily industrialized since the mid-1800s. The objectives of this study were to: quantify the present extent and magnitude of chemical contamination in surface sediments from the Study Area; evaluate the contamination in the Study Area relative to a reference area and surrounding regional waterways; assess the potential for adverse effects to aquatic organisms; and identify spatial gradients in concentrations that may indicate potential point-sources of chemicals. Because existing ecological communities center primarily on intertidal mudflats in the Study Area, composite surface sediment was collected from 15 mudflats to generate a realistic assessment of fish and wildlife exposure to sediment contaminants. This study showed that present concentrations of organic contaminants are elevated throughout the Study Area and are generally higher than concentrations in the reference area and regional waterways. A screening-level analysis showed that there is potential for adverse effects to sediment-associated organisms from a number of chemicals. No spatial trends were apparent for most compounds evaluated, consistent with the presence of multiple sources of chemicals in the Study Area. The exception is semivolatile compounds, which appear to be localized to specific mudflats, indicating potential point-sources of contamination for these chemicals.