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Wyświetlanie 1-3 z 3
Tytuł:
Characteristics of the staminate flower and pollen from autotetraploid Betula platyphylla
Autorzy:
Lin, L.
Yao, Q.
Xu, H.
Mu, H.
Jiang, J.
Powiązania:
https://bibliotekanauki.pl/articles/41710.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Opis:
Comparison of the staminate flower and pollen of Betula platyphylla between autotetraploid and diploid individuals may reveal the reason for cross sterility when an autotetraploid male parent is crossed with a diploid female parent. Staminate flowers and pollen from seven autotetraploid individual trees were examined. The morphologies of the staminate flower and pollen and pollen germination of these autotetraploid individuals were compared with diploid trees. The structure of the staminate flower did not differ between autotetraploids and diploids, whereas the size of the staminate flower was larger in the autotetraploids compared with the diploids. The mean diameter and pore depth of the pollen were significantly larger in autotetraploid individuals compared with diploids, and several abnormalities in pollen morphology were found commonly amongst pollen from the autotetraploid trees. The germination rate of pollen from autotetraploids was significantly inferior to that of diploids and there was a significant negative correlation between germination rate and the percentage of abnormal pollen. These results demonstrate that the autotetraploid should not be chosen as the male parent to obtain hybrid triploid progenies because the pollen is abnormal and results in low fertility despite its large size. The results provide important information for selecting and distributing parent strains with the aim of building seed orchards of triploid birch trees.
Źródło:
Dendrobiology; 2013, 69
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Seasonal dynamics in cambial activity and the formation of xylem and phloem in the branches of Cinnamomum camphora
Autorzy:
Dong, M.
Xu, Y.M.
Lin, H.
Li, X.Q.
Xia, Q.Q.
Powiązania:
https://bibliotekanauki.pl/articles/41385.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
seasonal dynamics
cambial activity
formation
xylem
phloem
branch formation
tree
tropical tree
Cinnamomum camphora
wood formation
phenology
Opis:
The cambial activity and periodicity of secondary xylem and phloem formation have been less studied in tropical tree species than in temperate ones. Cambium activity is the only source of timber production. Studies on its activity and xylem formation can provide helpful data for dendrochronology and possible factors that control tree growth, the yield and quality of wood. Cinnamomum camphora is an important fast-growing tree for furniture and sculpture wood in South China. Its dynamics of cambial activity was not reported. During the growth season in 2011, five trees of Cinnamomum camphora plantation were monitored on the campus of Huazhong Agricultural University in central china (located on 113°41’ to 115°05’ E and 29°58’ to 31°22’ N). Sampling time was from 13, February 2011 to 13, February 2012. Some small stems of 15–20 cm length were selected to sample in the middle of 2–3 years old health branches in the central crown of these trees. The observational study found that the cambium of camphor trees was active from March to October and dormant from November to February. Onset of cambial cell division was observed in early March, one week after sprouting of new buds. The morphology of the cells and number of cell layers in the cambium zone varied throughout the year. In early March, cambium reactivated with the rising of temperature, the cell wall was relative thick. The number of cell layers increased from 2–3 in middle Feb. to 3–5. In June, the number of cell layers in cambium reached the maximum of 5–7 in a radial direction. In mid March, phloem cells began to differentiate, followed by xylem three weeks later. The number of cell layers in immature phloem and xylem increased dramatically before mid June and the increment of cell layers in xylem was almost fifth times of phloem in the differentiating process. The phloem cells mainly stopped dividing new cells in end of October, but xylem cells were still in the activity a week later. The annual activities of cambium was in accordance with the air mean temperature change in 2011–2012. The results showed that the cambial activity and formation of xylem and phloem were related to the environmental factors, especially the temperature.
Źródło:
Dendrobiology; 2016, 75
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acer truncatum seedlings are more plastic than Quercus variabilis seedlings in response to different light regimes
Autorzy:
Guo, X.
Wang, R.-Q.
Wang, C.D.
Xu, F.
Zhao, S.
Guo, W.-H.
Powiązania:
https://bibliotekanauki.pl/articles/41339.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
Acer truncatum
seedling
Quercus variabilis
Chinese cork oak
plant response
light regime
irradiance acclimation
chlorophyll fluorescence
morphology
photoinhibition
Opis:
In this study, we investigated responses of the mid-successional species Acer truncatum Bunge and the late-successional species Quercus variabilis Blume to three solar illumination conditions: (1) constant low light (CL), (2) constant high light (CH) and (3) low light first and high light afterwards (LH). The last treatment was to simulate a canopy opening. Both species exhibited increases in biomass, totally and in part, and decreases in leaf water content, specific leaf area and chlorophyll concentrations in LH treatment compared to CL treatment. For A. truncatum, exposure to high light condition (LH) increased crown area, and decreased root to shoot ratio, stem mass ratio and leaf perimeter. However, for Q. variabilis, LH treatment increased stem diameter at ground height, effective quantum yield, photochemical quenching and decreased maximum photosystem II quantum yield. The biomass allocation pattern did not change in Q. variabilis among three light conditions. With respect to newly developed leaves, no significant differences were found in leaf size of Q. variabilis between LH treatment and CH treatment while that of A. truncatum decreased in LH treatment. All chlorophyll fluorescence parameters in newly developed oak leaves in LH treatment increased compared to those of CH treatment while no difference was found for A. truncatum between LH and CH treatment. A. truncatum displayed a greater overall plasticity than Q. variabilis although the oak seedlings have a greater plasticity with respect to chlorophyll concentration and chlorophyll fluorescence parameters. A. truncatum should be a better candidate for vegetation recovery, especially in places with heterogeneous light conditions.
Źródło:
Dendrobiology; 2016, 76
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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