Báo cáo lâm nghiệp: "Seasonal variations in photosynthetic activity of spruces as determined by chlorophyll fluorescence" ppsx

... were higher in winter (values of 0.55-0.68) than at the time of highest pho- Seasonal variations in photosynthetic activity of spruces as determined by chlorophyll fluorescence H.K. ... Lichtenthaler and Rinderle, 1988) permits a fast screen- ing of seasonal and short-term variations tosynthetic activity, e.g., in springtime (values of...

Ngày tải lên: 09/08/2014, 04:20

... above T 15 ). As a matter of fact, the decrease observed in F v /F m was due to a decrease in F m with no increase of F o , which may be interpreted as indicating a reversible increase of thermal ... steep increase of F o (Fig. 1), [4]. 2.3. Seasonal time course of thermostability of photochemistry During 2000, T c was recorded four times (beginning of April, beginni...

Ngày tải lên: 08/08/2014, 01:22

... determined at any time of test performance by means of seasonal indexes according to formula (3). Although the results of our experiment as well as the knowledge of other authors about the seasonal ... use in forestry practice, three methods that eliminate existing seasonal fluctuations are proposed. Seasonal indexes seem promising since they enable converting the observed...

Ngày tải lên: 07/08/2014, 10:21

... such as soil instability or damage due to the action of wind or snow, as well as biological, such as the weight of epiphytes or the weight of the stem and crown of the tree itself. Controlling ... tension. Because of the stiffness of the internal wood layers, most of the maturation stress in the outer layers of the tree is not released in situ [3]. This can be evide...

Ngày tải lên: 07/08/2014, 16:20

... density of indi- vidual rings. However, for wood density of cumulated rings, the repeatability showed a steady increase starting from 3 to 5 years of age at most of the sites. The increase of repeatability was ... signs of increase by the end of the 10-year-old period at any site. The radial growth (cumulated ring width) of poplar hybrids was initially fastest at the Saint-O...

Ngày tải lên: 07/08/2014, 16:20

... about 46% of N and 27% of P were released. Other studies, such as that of Piatek and Allen [24], N release was 710 X. Xu Figure 2. Percentage of mass remaining for different nutrient elements in the ... than dry mass loss would result from leaching. The rapid release of K and Mg in the early phase observed in the present study could be attributed to the physical removal by...

Ngày tải lên: 07/08/2014, 16:20

... not sufficient for ash species determination. Even when molecular markers are efficient tools for discriminating closely-related species (e.g. [13]), useful infor- mation can also be obtained by examining physiological ... first measure of the underdevelopment of the embryo, and this character is known to be involved in germination ability and evolution of seed dormancy [1,2,12]. Thus, m...

Ngày tải lên: 07/08/2014, 16:20

... seeds of beech were sam- pled in the vicinity of these plots, during autumn 1999. During 2000, seeds germinated and young seedlings grew in 400-cm 3 pots contain- ing a mixture of peat and pine ... using a SAS program (SAS Institute Inc., Cary, NC, USA) based on non-linear regression procedure of SAS, with optimisation of the repartition of experimental points between the two...

Ngày tải lên: 08/08/2014, 00:22

... couple. Non-specific esterases, malate dehydroge- nase and leucine amino-peptidase were investi- gated. The analysis of 583 males and 1 174 females grouped according to their origin was performed, colony ... of leucine amino-pepti- dase (EC 34111), the gels were immersed in a solution of 0.5 M boric acid. The acid solution was removed after 15...

Ngày tải lên: 08/08/2014, 18:21

... of the seedlings took place chiefly in the year of cutting and during the first vegetative sea- son of the coppice. The number of seedlings emerging in the course of ... left standing was based on good development and shape of the tree (this criterion led to decreas- ing ’quality’ as their number increased). After coppicing (March 1993...

Ngày tải lên: 09/08/2014, 04:20