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71.
Jan Čermák Jan Gašpárek Francesca De Lorenzi Hamlyn G. Jones 《Annals of Forest Science》2007,64(5):491-501
The objectives of this paper were (1) to provide general biometry data for an 80-year-old olive (Olea europea L., cv. Coratina) grove in Andria, southern Italy, and (2) to compare different methods for estimating leaf area distributions. Stand biometry was represented by a stocking density of 132 trees ha?1, mean spacing of 8.7 m and mean social area (proportional to spacing and tree size) of about 76 m2 per tree. Trunk total circumference averaged 110 cm and after subtraction of missing or dead parts of stems averaged 81 cm, projected area of crowns averaged 17.7 m2 and the mean tree height was 4.9 m. Leaf distribution was evaluated using calibrated ground-based side photographs through image analysis and through using a simple canopy-layer model (considering hollow volume within tree crowns) and double-Gaussian curves. The mean leaf size was about 5 cm2 (distributed in a log-normal manner over the range of 2 to 12 cm2). Considering whole tree crowns, the mean leaf density was about 2.6 m2m?3; the maximum leaf area occurred in canopy layers between 1.5 to 3 m, tailing with a steeper slope to the crown base and a less steep slope to the tree-top. The foliated volume of olive crowns (mean 33.2 m3) contained on average 145 thousand leaves of the total area of 72.6 m2. The corresponding leaf area index on the stand level (LAI grove = 0.96), was rather low due to low stocking density. However when taking into account only the projected crown areas (and avoiding free space between trees), the mean LAI reached about 3.5 (range from 1–7). The radial pattern of leaf distribution derived from image analysis indicated peak LAI rad values at a distance from the stem of about 60 to 70% of crown radius in trees of different size. The applicability of different approaches to the estimation of the necessary allometric parameters is discussed. 相似文献
72.
Brenda Colleen Clifton-Cardoso Marcelo Schramm Mielke José Roberto De Melo Rondinele Nascimento Querino 《New Forests》2008,35(1):15-31
Dimorphandra jorgei MF Silva (Caesalpinaceae) and Swartzia macrostachya Benth. var. riedelii Cowan (Fabaceae) are tree species from the southern Bahian Atlantic Forest, identified for the restoration of degraded areas.
The objective of this research is to study their seed germination and seedling growth to develop simple methods for seedling
production in small scale nurseries. Because the species have distinct dormancy and germination characteristics, the seeds
were submitted to different treatments. D. jorgei seeds were immersed in hot water, scarified and stored for 12 weeks in the laboratory environment (25°C). S. macrostachya seeds were submitted to different combinations of drying and storage in the laboratory environment or refrigerator (4°C).
Seedlings were submitted to two light treatments for 3 months: partial shade (52% of full sun) and full shade (12% of full
sun). In D. jorgei, the highest germination occurred for scarified seeds (87%) and for seeds stored for 12 weeks and then scarified (69%). In
S. macrostachya the undried control seeds had the highest germination, followed by that of the refrigeration storage treatment, without predrying
(99% and 97%, respectively). The average values for the growth parameters were greater in full shade for D. jorgei, while S. macrostachya seedlings showed greater growth rates in partial shade. Two months growth is recommended before D. jorgei seedlings are of the sufficient size and leaf number for field planting. On the other hand, a period of 4 months is recommended
for S. macrostachya, due to its relatively slow growth. 相似文献
73.
Anna Dupleix Domingos De Sousa Meneses Mark Hughes Rémy Marchal 《Wood Science and Technology》2013,47(6):1231-1241
There is a lack of quantitative data on the penetration depth and the amount of energy absorbed by green wood under infrared (IR) radiation. This lack of knowledge is a potential barrier to the development of IR heating as an alternative to soaking as a means of warming logs prior to peeling in the manufacture of plywood. Experimental measurements of normal hemispherical spectral reflectance and transmittance over the range 550–5,500 cm?1 wavenumbers on four wood species, beech, birch, Douglas-fir and spruce have brought new knowledge on mid-infrared absorption properties of green wood and removed some uncertainties. For instance, it is not possible to deliver energy deeper than up to 0.3 mm below the wood surface because 70–90 % of all incident IR radiation on the wood surface is absorbed in this layer. Some wood features, such as surface quality, the presence of knots and of free water in wood (the latter two having a more significant effect) influence the amount of energy absorbed. These results illustrate that IR radiation can heat the surface layers, but then heat penetrates deeper into the inside layers of wood by conduction. 相似文献
74.
The first records of the invasive pest Drosophila suzukii in the South American continent 总被引:1,自引:0,他引:1
Maríndia Deprá Jean Lucas Poppe Hermes José Schmitz Daniela Cristina De Toni Vera L. S. Valente 《Journal of pest science》2014,87(3):379-383
This paper presents the first report of the occurrence of Drosophila suzukii (Diptera: Drosophilidae) in South America. Several samples were collected during various seasons in 2012 and 2013, and a significant number of individuals were obtained and identified. Based on the data recorded during each sampling campaign, including the locality, temperature, time of year, and number of individuals collected, several conclusions were drawn about the development of this invasion in southern Brazil. 相似文献
75.
Transmission of resistance to common scab from the diploid to the tetraploid level via 4x-2x crosses in potatoes 总被引:1,自引:0,他引:1
Summary Diploid potato clones selected for their reaction to common scab and their ability to produce 2n male gametes were used in a series of crosses to a susceptible tetraploid female parent (cv. Shepody). In addition, two tetraploid clones were also selected for their reaction to common scab and crossed with Shepody as a female parent. Results indicated that resistance to common scab can be effectively transmitted from the diploid to the tetraploid level via 4x-2x crosses. Diploid parents producing 2n pollen via either first division or second division restitution can be used to transmit scab resistance. A relatively small proportion of resistant individuals could be recovered from susceptible x susceptible crosses in both 4x-2x and 4x-4x combinations. The data support a previously developed hypothesis that scab resistance is relatively simply inherited. 相似文献
76.
77.
D. P. De Vries 《Euphytica》1965,14(1):78-82
In 9–13 year old cherry seedling populations, totalling 1,033 individuals, a preliminary selection was made in 1963, for field resistance to bacterial canker (Pseudomonas syringae
van Hall).The field resistance of the three cherry species used, P. avium, P. cerasus and P. avium × P. cerasus, has shown to be low, high and very high, respectively. 相似文献
78.
Summary A spring wheat genotype which produces somatic embryos in vitro, after short and long-term culture, was tested for its ability to sexually transmit this embryogenic trait. Reciprocal crosses were performed between a embryogenic line and a nonembryogenic variety.Immature embryos were cultured on Murashige and Skoog medium plus 2 mg/l 2,4-dichlorophenoxyacetic acid, gelled with 5.5 g/l agarose. Somatic embryogenesis was not expressed in the F1's. In contrast, from several hundred immature embryos of the F2 generation of one cross, 10.7% and 1.6% expressed somatic embryogenesis in short and long-term cultures respectively. These percentages of embryogenic: non-embryogenic fits a model of a few complementary genes. The embryogenic capacity of the F2 genotypes depends on the presence of recessive alleles at these gene loci. The long-term wheat somatic embryogenesis capacity requires a more complex mechanism than the short-term one.Abbreviations CS
Chinese Spring
- Aq
Aquila
- E
Embryogenic
- NE
Nonembryogenic
- SC
Subculture 相似文献
79.
Summary Thirty, one-season-old Rosa canina Inermis seedlings (8–12 mm in diameter) were grown in the greenhouse. After 5 months, single-node softwood cuttings were made of each plant. Analysis of variance demonstrated marked differences between the internode length, number of leaflets per leaf and the leaf area of the original seedling, and between the time of axillary bud-break, axillary sprout length and weight of adventitious roots of their 23-day-old cuttings. Clonal root weight of cuttings was highly significantly correlated with: number of leaflets per leaf (r=–0.65), leaf area (r=+0.65), and days to axillary bud-break (r=+0.62). The origin of heterogeneity among Inermis seedling rootstocks, its probable effect on the flower production of cut roses and its possible use in the selection for clonal rootstocks are discussed. 相似文献
80.
Stefan Fleck Nathalie Cools Bruno De Vos Henning Meesenburg Richard Fischer 《Annals of Forest Science》2016,73(4):945-957