Diagnostic Accuracy of Estimating the Number of CL and Ovarian Volume to Predict Superovulatory Response in Dairy Cattle     

N Kanuya  M Schmidt  M Chriél  T Greve 《Reproduction in domestic animals》1997,32(6):291-296

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Relationships between nutrient composition of flowers and fruit quality in orange trees grown in calcareous soil     

Pestana M  Beja P  Correia PJ  de Varennes A  Faria EA 《Tree physiology》2005,25(6):761-767

To determine if flower nutrient composition can be used to predict fruit quality, a field experiment was conducted over three seasons (1996-1999) in a commercial orange orchard (Citrus sinensis (L.) Osbeck cv. 'Valencia Late', budded on Troyer citrange rootstock) established on a calcareous soil in southern Portugal. Flowers were collected from 20 trees during full bloom in April and their nutrient composition determined, and fruits were harvested the following March and their quality evaluated. Patterns of covariation in flower nutrient concentrations and in fruit quality variables were evaluated by principal component analysis. Regression models relating fruit quality variables to flower nutrient composition were developed by stepwise selection procedures. The predictive power of the regression models was evaluated with an independent data set. Nutrient composition of flowers at full bloom could be used to predict the fruit quality variables fresh fruit mass and maturation index in the following year. Magnesium, Ca and Zn concentrations measured in flowers were related to fruit fresh mass estimations and N, P, Mg and Fe concentrations were related to fruit maturation index. We also established reference values for the nutrient composition of flowers based on measurements made in trees that produced large (> 76 mm in diameter) fruit.  相似文献   

The effect of compression and incision on wood veneer and plywood physical and mechanical properties     

Maija Kymäläinen  Akio Yamamoto  Kasperi Sokka  Lauri Rautkari 《Wood material science & engineering》2020,15(2):97-103

ABSTRACT

Drying takes the largest share of energy in plywood production, and varying moisture content of veneers necessitates re-drying that often leads to over-dry veneers with deactivated surfaces, which may promote imperfect bonding. In order to decrease the drying time, reduce the need for re-drying of veneers, and improve the quality of plywood, birch and spruce veneers were subjected to pre-treatment by cold compression, incision, or a combination of the two. The effects of pre-treatment on the veneer and plywood quality were assessed by standard tests. Compression had a beneficial effect on water removal of the wettest veneers (spruce sapwood (SW) and birch), but some thickness reduction was observed in the veneers as well as the finished birch plywood. Compression led to thickness reduction of spruce veneers, but had no effect on SW plywood thickness likely due to higher viscoelasticity. Both compression and the combination of incising and compression levelled the moisture variation within the compressed stacks. Incision improved the modulus of elasticity of birch plywood, shear strength of SW plywood, and both bending and shear strengths of heartwood plywood. Higher surface pressure decreased the drying time of spruce SW in both plain compression and combined incision and compression pre-treatment.  相似文献   

Daily time course of whole-shoot gas exchange rates in two drought-exposed Mediterranean shrubs     

Nogués S  Munné-Bosch S  Casadesús J  López-Carbonell M  Alegre L 《Tree physiology》2001,21(1):51-58

Effects of drought on water relations, whole-shoot gas-exchange characteristics, and pigment and zeatin concentrations were investigated in the Mediterranean shrubs rosemary (Rosmarinus officinalis L.) and lavender (Lavandula stoechas L.). Two-year-old, greenhouse-grown plants were placed in a whole-shoot gas-exchange measurement system and subjected to 10 days of drought, resulting in severe water stress, and then re-watered for 5 days in order to study their recovery. Water stress resulted in a significant decline in maximum whole-shoot net CO2 assimilation rates (An) for both species that was associated with reductions in leaf area and stomatal conductance. Because shoot dark respiration rate (Rd) was less sensitive to water stress than An, shoot Rd/An ratio increased from about 15 to 95% during water stress. No major changes in chlorophyll and carotenoid concentrations of rosemary leaves were observed during the experiments, but chlorophyll and carotenoid concentrations fell significantly in water-stressed lavender leaves. Zeatin concentrations were higher in rosemary leaves than in lavender leaves during water stress. After re-watering, whole-shoot An and Rd rapidly recovered to their pre-drought rates.  相似文献   

Shoot development and dieback in progenies of Nothofagus obliqua     

Javier Puntieri  Javier Grosfeld  Marina Stecconi  Cecilia Brion  María Marta Azpilicueta  Leonardo Gallo  Daniel Barthélémy 《Annals of Forest Science》2007,64(8):839-844

Shoot growth and dieback were compared among progenies of nursery-grown seedlings of Nothofagus obliqua belonging to seven progenies of the same provenance (Quila-Quina, Argentina). First-year shoots consisted of one growth unit (GU) and second-year shoots of one or two GUs. The probability of development of two GU was similar for all progenies. Progenies were different in terms of shoot size, terminal bud abscission, the extent of shoot dieback after shoot extension and the node of origin of the relay shoot on the first shoot. Plants with a second-year shoot consisting of two GUs had a thicker stem and more nodes than those with single-GU shoots. The selection of N. obliqua seed trees based on architectural traits suitable for forestry development at specific sites must contemplate variability among progenies and their probabilities of successful development under different conditions.  相似文献   

Spatial pattern of the density of Armillaria epiphytic rhizomorphs on tree collar in an oak stand     

B. Marçais  O. Caël 《Forest Pathology》2006,36(1):32-40

The density of Armillaria gallica epiphytic rhizomorphs on tree collar was mapped in a young stand of pedunculate oaks (Quercus robur). A quick method to estimate the rhizomorph density was developed, investigating 19 trees, and was used in the subsequent study. The method consists of measuring the frequency of rhizomorphs present on a grid applied to an exposed small area of the tree collar. The pattern in tree collar rhizomorph density was closely related to the pattern of stump colonization by Armillaria and stumps were therefore important as inoculum sources. Rhizomorph density on tree collar showed a strong aggregated spatial pattern which could not be explained by variability in the soil characteristics, in particular waterlogging, or by a spatial pattern in tree vigour. Moreover, rhizomorph density on tree collar did not depend on their dominance status.  相似文献   

A comparison of two stand table projection methods for young Eucalyptus nitens (Maiden) plantations in Chile     

Guillermo Trincado V.  Raúl Quezada P.  Klaus von Gadow 《Forest Ecology and Management》2003,180(1-3):443-451

The study compares two methods of stand table projection based on data from young Eucalyptus nitens (Maiden) plantations in Chile. The projected diameter distributions were estimated using the methods proposed by Nepal and Somers (1992) [For. Sci. 38 (1992) 120] and Cao and Baldwin (1999) [For. Sci. 45 (1999) 506]. The evaluation compared the observed and estimated diameter distributions for different projection intervals, using the Kolmogorov–Smirnov test and an error index called ‘relative discrepancy’. The evaluation showed that both methods are suitable for application in the Eucalypt plantations. However, the method proposed by Nepal and Somers proved to be more accurate, especially when the projection period extends over 4 years or more. Expected error and bias for the observed and estimated total and merchantable volumes at stand level were also evaluated. The observed error and bias were relatively low for both methods; however, some differences were detected when the volume distributions were analyzed at diameter class level.  相似文献   

A method for automatic collimator alignment in microdensity measurements     

K. Pernestål  B. Jonsson 《Wood Science and Technology》1996,30(2):91-97

Summary In microdensitometry, based on X-ray absorption technique and a direct, electronic detector technique, it is usually not possible to observe the collimator and its alignment to the annual ring under investigation during the measurement. In this paper a method for automatic alignment of the collimator to the ring is described. The operating technique is based on an optimization of the resolution of the instrument at every annual ring while the collimator is rotated to the best position. The procedure has been in use a number of years and has proven itself to be efficient and reliable. The theory of operation for the procedure is described and its software structure is shown in a block diagram. Advantages and limitations of the procedure are discussed.The funding of this project is made by Nordbanken. The density profile in Fig. 5 has been recorded by Mr. Bo Larsson and is published with his kind permission  相似文献   

Crystalline structure of heat-treated Scots pine [<Emphasis Type="Italic">Pinus sylvestris</Emphasis> L.] and Uludağ fir [<Emphasis Type="Italic">Abies nordmanniana</Emphasis> (Stev.) subsp. <Emphasis Type="Italic">bornmuelleriana</Emphasis> (Mattf.)] wood     

Mehmet Akgül  Esat Gümüşkaya  Süleyman Korkut 《Wood Science and Technology》2007,41(3):281-289

The aim of this study was to determine changes in crystallinity and crystalline unit cell type of heat-treated Scots pine (Pinus sylvestris L.) and Uludağ fir (Abies nordmanniana stev. subsp. bornmuelleriana Mattf.) wood samples by means of FT-IR spectroscopic method. Heat treatment was applied on the test samples in an oven at three different temperatures (120, 150, and 180°C) and for two different periods of time (6 and 10 h) under atmospheric pressure. It was designated that crystallinity of both Scots pine and Uludağ fir wood samples increased during heat treatment depending on the duration. However, monoclinic structure in crystalline unit cells of Scots pine and Uludağ fir wood samples converted to triclinic structure when heat treated. It was estimated that monoclinic structure was dominant in the crystalline unit cell. It was established that the crystalline structure of Scots pine wood samples was more affected by heat treatment than that of Uludağ fir wood samples.  相似文献   

Effect of temperature and compression on the mechanical behavior of steam-treated wood   总被引：2，自引：0，他引：2  

Petri P. KÄrenlampi  Pekka TynjÄlÄ  Pasi StrÖm 《Journal of Wood Science》2003,49(4):298-304

The mechanical behavior of steamed spruce wood changes dramatically with compression along the grain, the change being much more moderate perpendicular to the grain. The stiffness decrement due to increased temperature is greatest in the tangential material direction. The stiffness decrement due to compression is greatest along the grain. Compression to 80% compressive strain at 131°C inverts the order of the material directions regarding stiffness, the stiffness being the least along the grain. Plastic strain due to compression is greater at higher temperatures. The compression-induced decrement of stiffness along the grain is greater at higher temperatures, but the off-axis decrement of stiffness is less at higher temperatures.  相似文献