Enhanced Seedling Root Development in Eight Conifer Species Induced by Naphthalene Acetic Acid

Seedlings of eight conifer species, Pinus contorta, Pinus sylvestris,Pinus nigra, Larix kaempferi, Picea abies, Picea sitchensis,Pseudotsuga, nenziesii and Abies grandis, were treated withauxin, in pot and nursery experiments. Dilute solutions of naphthaleneacetic acid (NAA) were applied at two treatment times, justbefore and just after cotyledon expansion. Lateral root numberswere increased by up to 20 times on responsive species. Sensitivityvaried considerably, the three pine species showing a much greaterresponse than the two species of spruce. In most cases the meannumber of induced roots increased steadily with increasing auxinconcentration. Forest nursery results showed that NAA couldprovide an inexpensive method for stimulating lateral root formationnear the soil surface. Practical nursery aspects of treatmentare briefly discussed.     

Hydrochemical Fluxes and their Effects on Stream Acidity in Two Forested Catchments in Central Scotland

The hydrochemical fluxes and budgets have been determined fortwo forested catchments, including inputs, tree throughfalland stemflow, soil water throughflow and output streams. Themajor vegetational induced differences are the enrichment ofsodium, chloride, sulphate and particularly hydrogen by Sitkaspruce compared to Norway spruce. These increased concentrationsare primarily due to vegetation interception along with crownleaching, both of which contribute to sulphate enhancement.Soil throughflow and consequent stream chemistries reflect thesespecies effects with additional enrichment both due to geologicalweathering of base cations as well as possible desorption ormineralization processes. Norway spruce vegetation and the associatedpodzolic soils show no net stream acidification (pH 4.61) ofinputs (pH 4.65), whereas Sitka spruce on gleyed soils showconsiderable stream acidification (pH 4.02) compared with similarinputs (pH 4.50). Both streams have similar sulphate concentrations,but this important mobile anion is associated primarily withhydrogen in the Sitka spruce dominated Kelty catchment whereasat Chon it is associated with base cations as well as hydrogen.     

Antimicrobial activity of four Artemisia species of Iran

The antimicrobial activities of methanol extracts of four species of Artemisia species of Iran are reported.     

Activity of blue green microalgae extracts against in vitro generated Staphylococcus aureus with reduced susceptibility to vancomycin

Blue green microalgae have been identified as one of the promising groups of organism from which biochemically active natural products have been isolated. Aqueous and organic extracts of nine blue green microalgae strains were screened against in vitro generated vancomycin intermediate resistant Staphylococcus aureus (VISA) strains. Aqueous extracts of all the blue green microalgae cultures were found to be inactive, while all the organic (hexane, chloroform and methanolic) extracts of Anabaena virabilis and Anabaena sp. showed activity against VISA strains with MIC of 32-64 mug/ml.     

Production of glucosinolate hydrolysis products in Farsetia aegyptia suspension cultures following elicitation

Levels of glucosinolates in Farsetia aegyptia var. ovalis suspension cultures were monitored after treatment with yeast extract, chitosan, methyl jasmonate, ampicillin, and Phytophthora infestans autoclaved mycelia as elicitors. Glucosinolates were identified, and an estimation of their levels obtained from their hydrolysis products. Yeast extract improved glucotropaeolin (benzyl-glucosinolate) and glucocheirolin [3-(methylsulfonyl)propyl-glucosinolate] accumulation, and production of sec-butyl, isobutylglucosinolate and gluconasturtiin (2-phenylethyl-glucosinolate) was only detected in yeast elicited cultures. Increases were shown in glucotropaeolin levels in cultures elicited using methyljasmonate, and chitosan and methyljasmonate in combination.     

Nitrogen contribution by multipurpose trees to rice and cowpea in an alley cropping system in Sierra Leone

In an alley cropping experiment, a study was carried out on N₂ fixation by Gliricidia sepium, nitrogen (N) accumulation by prunings of Gliricidia, Senna siamea (formerly Cassia siamea) and Gmelina arborea, and the N contribution to associated crops of rice and cowpea.Total N accumulated by the hedgerow trees ranged from 297–524 kg N ha^–1 on average but varied between tree species and depended on the growing season. Gliricidia sepium accumulated 370 kg N ha^–1 on average and more than half of this came from fixation. Senna siamea and Gmelina arborea served as reference trees for estimating N₂ fixation. The estimates of N₂ fixation using Gmelina as a reference gave higher estimates than those using Senna.Although the dry matter and nitrogen yields of prunings from the hedgerow trees were high, their relative nitrogen contribution to the associated crops was generally low ranging from 5 to 29%. Higher crop yields and nitrogen contribution were observed with Gliricidia sepium prunings. The low N contribution from prunings was attributed to the lack of synchronization between the N released from the prunings and the crop's demand for N.     

Temperature control of the development of frost hardiness in two populations of Leptospermum scoparium

Seedlings of Leptospermum scoparium J.R. et G. Forst (manuka) originating from seed from a low altitude coastal site (Auckland) and from a high altitude inland site (Desert Road) were grown for 96 days in four controlled environments to compare the relationship between growth temperature and frost hardening. Day/night temperature treatments were 12/6, 12/3, 12/0 and 12/-3 degrees C. Frost hardiness was determined at 14-day intervals by exposing whole seedlings to temperatures ranging from -2 to -8 degrees C. Frost damage differed significantly between the two populations: Desert Road seedlings were less affected than Auckland seedlings. At all growth temperatures, the time courses of frost hardiness of both populations followed curvilinear relationships reaching a maximum hardiness at about Day 50, after which the seedlings spontaneously dehardened. The rate of frost hardening increased linearly with decreasing temperature from 6 to 0 degrees C, but thereafter, no further increase occurred with decreasing temperature to -3 degrees C. The frost hardening process was more sensitive to temperature in the Desert Road seedlings than in the Auckland seedlings, and this difference may account for the intraspecific variation in frost hardening capacity of this species. Comparisons with Pinus radiata D. Don and Lolium perenne L. indicated that interspecific variation in frost hardening capacity can also be accounted for by differences in the sensitivity of the hardening process to temperature.     

Characterization of the correlation structure of lumber strength properties

Spatially averaged data from the literature for along-the-length correlation of lumber flatwise bending modulus of elasticity and tensile strength was analyzed to determine the correlation of the base process for each property. The cross correlation between the two properties was also examined. The exponential correlation function, equivalent to a first-order auto-regressive process, was the best model for both correlation and cross correlation, based on the sum of squared errors between the correlations from the test data and the fitted model. The fitted functions can be used to generate correlation and cross correlation information for spatially averaged processes averaged over lengths different from the lengths used to obtain the test data.     

Genetic variation in architectural seedling traits of Patagonian cypress natural populations from the extremes of a precipitation range

? Species distributed along wide environmental ranges are expected to be either plastic or adapted to local optima. The elucidation of which of these alternatives prevails, is crucial in planning breeding and conservation strategies for not yet domesticated species. Austrocedrus chilensis (Cupressaceae) is the most commercially important conifer of the temperate forests of Argentina and the target of a domestication program. A steep precipitation gradient characterizes its Argentinean range.

? Variation within and differentiation among four natural populations of this Patagonian cypress representative of two contrasting precipitation regimes (>1 300 and 330 mm per y) were assessed by analyzing several morpho/architectural traits in one-year-old seedlings grown in a greenhouse.

? Progenies from one of the two xeric populations did not differ from those corresponding to both humid-site populations. The two most variable populations in terms of additive genetic variance belonged to contrasting precipitation regimes. Differentiation among populations was low as measured by each and every variable (average Q _st = 0.088). Morphological traits related to the main axis size would have a dubious adaptive meaning.

? The results suggest that the Patagonian cypress would have not evolved genetic pools adapted to local optima, and thus it appears to be a phenotypically plastic species, at least regarding growth at juvenile age.