In other species such as tobacco and cabbage, selective destruction of tapetal cells can disrupt the formation of pollen grain
and lead to sterility (Cho et al.
Description: Pollen grain
, monocolpate, overall amb elongate oval to fusiform, colpus distinct, running entire length of grain with a tendency to become narrow in middle with slightly expanded extremities.
velocity fields around stems bearing ovules.
On average, the genotypes showed high pollen grain
viability, ranging from 93 to 98.
examined under microscope can be seen in a polar or equatorial view.
Predominant pollen grains
(PP, comprising more than 45% of the nectariferous pollen grains
counted) belonged to Eucalyptus in two samples of Apis (Amparo-A and Lins-A) and one of Citrus (Itaberaba-A).
Because the growth medium was optimized for the pistil experiment, only a few pollen tubes emerge from pollen grains
without contacting a pistil (Figure 3D, asterisk).
But other combinations seemed to pit pollen grain
against pollen grain
Cyclantherinae is characterized by pollen grains
4-8 colporate and punctitegilate (Marticorena, 1963; Jeffrey, 1990; Shridhar & Singh, 1990; Stafford & Sutton, 1994; Khunwasi, 1998), and Sicyinae by pollen grains
715 colpate and echinate (Marticorena, 1963; Shridhar & Singh, 1990; Khunwasi 1998).
Species can be identified from pollen grains
, fragments of seeds or roots, wood, faecal samples, stomach contents or environmental samples collected from the air, soil or water.
This process removes residues and other substances from the surface of the pollen grain
, revealing the exine structure.
The anther was gently squashed on a slide, covered with a 22 x 50 mm cover slip and the pollen grains
were counted under 10x objective of a compound microscope.