The pollen grain then takes in moisture and begins to germinate, forming a pollen tube that extends down toward the micropyle opening in the ovule.
42.
Sperm cells of Pinophyta and Gnetophyta are without flagella, and are carried by the pollen tube, while those of Cycadophyta and Ginkgophyta have many flagella.
43.
The germinated pollen tube must then drill its way through the nutrient-rich style and curl to the bottom of the ovary to reach the ovule.
44.
Activation involves the development of actin filaments throughout the cytoplasm of the cell, which eventually become concentrated at the point from which the pollen tube will emerge.
45.
Under a constant electric field of 1 V / cm pollen tubes of " Camellia japonica " have been reported to grow towards the negative electrode.
46.
Exo-PGs involved in pollen tube growth need Ca 2 + for maximal enzymatic activity and can be inhibited by high concentrations of NaCl, citrate, and EDTA.
47.
The pollen tube growth is similar to the infection thread development in that infection threads grow in a polar manner that is similar to a pollen tubes polar growth towards the ovules.
48.
The pollen tube growth is similar to the infection thread development in that infection threads grow in a polar manner that is similar to a pollen tubes polar growth towards the ovules.
49.
He describes the standard arrangement in angiosperms the nucellus joined by the chalaza to the integuments, which surround the nucellus except at the micropyle, through which the pollen tubes enter.
50.
The four resulting cells consist of a large tube cell that forms the pollen tube, a generative cell that will produce two sperm by mitosis, and two prothallial cells that degenerate.
