4 天之前 · Pollen Description. Grains are usually spheroidal with a thin exine. The grains are 1-aperturate with a faint circular pore. The pollen grains are uniform within the family and different genera are difficult to distinguish. Grains are 25-36 micrometers in diameter.

2011年6月17日 · Pollen grains of several Cupressus species were observed using various techniques and methodologies, under light and fluorescence microscopy, phase-contrast microscopy, confocal microscopy, scanning electron microscopy, and an environmental scanning electron microscope.

2010年6月16日 · Rehydrated pollen grains collected from 20 Asian, Afro-Mediterranean and American cypress species were measured under a light microscope. The size of the pollen grains and the percentage of intine in relation to the pollen grain diameter were significantly different between Old World and New World species.

2020年2月10日 · Cupressaceae pollen diffusion was detected by means of two sampling methods: moss cushions, which are able to accumulate pollen grains for several successive years, and volumetric sampler,...

Key results: A temporary structure located just above the pore was observed on Cupressus pollen grains, as well as on other taxoid-type pollens. It is hemispheric, layered, and consists of polysaccharides and proteins. The latter are confined to its inner part.

2017年4月11日 · All Cupressaceae species produce spherical pollen grains very similar in appearance (Fig. 2a). In the Cupressus genus, the mean size of hydrated pollen grains varies from 25 to 40 μm (Fig. 2b), and they differ based on their geographical origins.

microsporangium contains a ge number of uniform pollen grains (Fig.lar 3I) which are surrounded by the wall of the sporangium and two inner layers of tapetal tissue (Fig. 2D). 4 Discussion . 4.1 Comparison of pollen cones among Cupressus. Typical cupressaceous pollen cones are unbranched, consisting of several microsporangiophores,

Pollen morphology and u~rastructuru in most genera of the Cu pressaceae has been studied using light, scanning electron and transmission electron microscopy.

We have conducted the study of ultrastructural changes of wall and cytoplasm of Plantago lanceolata (English plantain) pollen grains during the first 10 min of hydration and activation...

The abundance of Cup a 3 in pollen grains under polluted air conditions indicates that these cypresses intensify their activity as a defense from environmental pollution, thus strengthening their allergenicity.