The pollen grain is the carrier of the male gametes or their progenitor cell, in higher plants. In a single unit, each grain contains all the genetic information required to specify an entire haploid plant organism (for example, pollen embryoids in tissue culture), or to unite with the ...
The pollen grain develops from a microspore in the microsporangium and completes its development after pollination, that is, its transfer into the pollen chamber of the ovule (in gymnosperms) or to the stigma of the pistil (in angiosperms). It has two membranes: the external one, or the ...
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Pollen Under The MicroscopeMethods, Techniques and Observations What is Pollen? Pollen is a small grain that consists of a few cells. To the naked eye it appears as a yellowish (pale yellow) dust-like substance that is either dispersed by wind or insects....
FRENGUELLI, G., FERRANTI, F., TEDESCHINI, E., ANDREUTTI, R., 1997: Volume changes in the pollen grain of Corylus avellana L. (Corylaceae) during development. Grana 36, 289-292.Frenguelli, G., Ferranti, F., Tedeschini, E. and Andreutti, R. 1997. Volume changes in pollen ...
Cupules are borne helically on a branched elaborated axis and each cupule contains one or two seeds. The presence of a bract is not confirmed but the whole structure may have been borne in the axil of a bract or leaf. Individual cupules are not subtended by a bract. e, Umkomasia quadri...
It was widely accepted based on chemical and molecular genetic analysis that sporopollenin contains phenolics and polyhydroxylated aliphatics that are covalently coupled by ether and ester bonds34. However, the chemical structure of sporopollenin requires further study. In recent years, Fourier ...
A kernel of corn contains the food supply for the plant to get started. The kernel soaks up water, swells, and bursts. Then the roots begin to grow down. The roots absorb water and food for the plant. Next the corn plant sprouts above ground. ...
BJ2 contains the first recorded presence of maize (Zea mays) in our profile at ca. 2900 BCE (1σ, 3100-2500 BCE). Between 3200 and 2000 BCE, a continuous increase in Combretaceae/Melastomataceae pollen is recorded (2–16%) through this zone. At 3200 BCE, high abundances of forest ...
Pollen grain viability and starch presence in pollen were followed during the long blooming period (May-November) of Parietaria judaica, the most widespread pellitory in Italy, responsible for many cases of allergic diseases. Observations were carried out near Siena (Tuscany), in the years 1978 ...