Weather factors controlling growth of Oriental beech are on the turn over the growing season

A better understanding of the ecophysiological basis of wood formation by monitoring radial growth over the whole vegetation period may help to explain possible discrepancies between long-term average climate–growth relationships and short-term climatic impacts on tree growth. To understand how growth–climate associations of Oriental beech vary throughout a vegetation period, we studied seasonal growth patterns of high-elevation beech trees growing in the north of Iran by collecting wood anatomical micro-cores in 10 to bi-weekly intervals and measuring stem increment with high-resolution electronic dendrometers. Wood formation was for two consecutive years with contrasting inter-annual climate conditions (2011 and 2012). We divided the growing period into three equal time phases and related daily climate variability to the cambial growth in each phase. The pattern of climate–growth relationships varies over a complete growing season and between years: in both study years, trees responded homogenously at the beginning and at the end of the growing season, but showed opposing influence of relative humidity during spring and early summer (June and July). Temperature as the main driver of xylogenesis had a stimulating effect on growth at the beginning of the growing season, but had negative effects on radial increment during late June and July mainly due to the excess of ambient temperatures over an optimum threshold. Higher temperature in late June and July 2011 compared with those of 2012 led to a significantly narrower tree ring in 2011, despite the similar sums/means of annual climate parameters in these two years. Since regional climate change scenarios expect higher temperature and reduced moisture conditions in future, radial growth of beech in the north of Iran may be adversely affected.     

Proliferation of functional hair cells in vivo in the absence of the retinoblastoma protein

In mammals, hair cell loss causes irreversible hearing and balance impairment because hair cells are terminally differentiated and do not regenerate spontaneously. By profiling gene expression in developing mouse vestibular organs, we identified the retinoblastoma protein (pRb) as a candidate regulator of cell cycle exit in hair cells. Differentiated and functional mouse hair cells with a targeted deletion of Rb1 undergo mitosis, divide, and cycle, yet continue to become highly differentiated and functional. Moreover, acute loss of Rb1 in postnatal hair cells caused cell cycle reentry. Manipulation of the pRb pathway may ultimately lead to mammalian hair cell regeneration.     

Prophylactic and therapeutic effects of a novel granulated formulation of Artemisia extract on broiler coccidiosis

Purpose

Coccidiosis is an important parasitic disease in poultry industry. Owing to the development of drug resistance against Eimeria and concerns about drug residues, attentions toward the alternative compounds including herbal medicines have been increased. This study aimed to examine the prophylactic and therapeutic effects of a new formulation derived from Artemisia sieberi extract on avian coccidiosis.

Methods

The extract was obtained from A. sieberi using petroleum ether, and then, it was formulated into a wet granule. Three hundred and sixty 1-day-old broilers were divided into six groups, each with three replicates (n?=?20); the first group was chosen as the noninfected control group and the remainders were challenged by oral administration of 250,000 oocysts of Eimeria tenella per chick on day 21. Group 2 (as nontreated control) received no treatment, but group 3 (as prophylactic group) received 0.5 mg/kg artemisinin 10 days before challenging with E. tenella. However, groups 4, 5, and 6 received 1 mg/kg artemisinin on the next day and at 24 and 48 h after the challenge, respectively, for 5 days. Mortality rate, bloody diarrhea score, lesion score, and oocysts per gram (OPG) of feces were used to determine the anticoccidial effects of the formulation.

Results

The granule significantly (p?<?0.05) reduced mortality, diarrhea, and lesion score in the treated groups. The OPG output was also significantly (p?<?0.0001) reduced in the groups that received formulation. However, there was no significant difference between the prophylactic and therapeutic groups.

Conclusion

The results suggested that this new formulation is a promising herbal medicine that can be used as a prophylactic or therapeutic product to control avian coccidiosis.     

Investigation on transversal variation of poplar tension wood quality using ultrasound wave parameters

Transversal variations of some ultrasound wave parameters (phase velocity, group velocity, attenuation coefficient and acoustic radiation) were measured from the pith to the bark of poplar tension wood discs in different orthotropic directions. Over 80 cubic specimens of 2 × 2 × 10 cm³ (radial, tangential and longitudinal, respectively) were prepared and tested acoustically. Samples containing tension woods were separated from normal ones using anatomical experiments. Results showed acoustical behaviour of normal and tension wood improved in longitudinal direction while the distance between pith and bark increased; also, wave parameter variations were less important in radial and tangential directions. In addition, phase velocity and acoustic radiation – which significantly varied – were the best parameters for quality assessment of poplar wood compared with group velocity and attenuation coefficients. Since samples near the bark were acoustically better than counterparts near the pith, they could be used in products requiring more strength, like lumber. Finally, acoustic radiation and phase velocity were correlated more strongly with density than group velocity and attenuation.     

Effect of canopy gap size and ecological factors on species diversity and beech seedlings in managed beech stands in Hyrcanian forests

We studied the species diversity of the herb layer and ecological factors in harvest-created gaps in beech stands under a single-tree selection system in Northern Iran. To determine diversity, the number of beech seedlings, and other ecological factors, 16 gaps were selected and subplots of 5 m2 were positioned at the centre and at the cardinal points of each gap. Species richness and Simpson diversity index increased with increasing gap area as did numbers of seedlings. With increasing humus layer thickness, species richness declined but the Hill evenness index increased. Species richness increased with increasing light availability. There was no relationship between crown radii of beech trees and diversity indices. Correlations between environmental factors and numbers ofindividuals of some species in the herb layer were not significant except in a few cases. The results help explain the effects of man-made gaps on the dynamics of managed beech stands and this benefits evaluation of silvicultural operating plans.     

PHYSIOLOGICAL RESPONSE OF SPRING DURUM WHEAT GENOTYPES TO SALINITY

Soil salinity is a serious threat in many parts of Iran, which negatively affects plant production. In order to investigate response of durum wheat to salinity, two genotypes, ‘Turkey 506’ (salt tolerant) and ‘Egypt 557’ (salt sensitive), were grown in hydroponic conditions, exposed to various salt levels (0, 50, 100, 150 and 200 mmol NaCl) in a split split plot based on randomized complete block design with three replications of each treatment. Salinity stress decreased relative water content (RWC), potassium content, potassium/sodium ratio, chlorophyll a (chla), chlorophyll b (chlb), and total chlorophyll contents, efficiency of photosystem II (F_v/F_m) and membrane stability index (MSI), and increased sodium, proline and soluble sugars concentrations and ratio of chla/chlb in both genotypes. The decrease in RWC, chla, chlb, F_v/F_m, and MSI were significantly higher in ‘Egypt 557’ than ‘Turkey 506’. ‘Turkey 506’ showed higher content of potassium, potassium/sodium ratio, proline, and soluble sugar concentrations as well as lower sodium content as compared with ‘Egypt 557’. The salinity tolerance of ‘Turkey 506’ is associated with higher RWC, potassium content, osmolyte concentrations, chlorophyll contents, F_v/F_m ratio, and maybe more vacuole sequestration of sodium.     

Isolation and identification of a lipase producing Bacillus sp. from soil

Lipase production in an indigenous lipolytic Bacillus sp. was detected in media containing Tributyrin-Tween 80 and Rhodamine B-Olive oil. The statistical Taguchi model was used to predict the optimum experimental conditions for bacterial growth and lipase production. Partial optimization was carried out for selection of salt base, oil, glucose, NH4Cl and yeast extract concentrations, inoculum density, pH and agitation. Maximum lipase activity was detected in the cell free supernatants of cultures grown in a medium containing 10 g L(-1) yeast extract, 15 g L(-1) NH4Cl, 3 g L(-1) K2HPO4, 1 g L(-1) KH2PO4, 0.1 g L(-1) MgSO4 x 7H2O, 2 g L(-1) glucose, 0.6 mM MgCl2 and 15 ml L(-1) olive oil, pH 8.5 at 30 degrees C for 24 h and low agitation. The amount oflipase produced in the designed medium was in agreement with the predicted values by the statistical method. 16S rRNA cloning and sequencing identified the test organism as Bacillus pumilus.