Hypersensitive reaction and callose formation were two important resistance mechanisms.
In the grasses the pollen tube is blocked at the stigma surface with pectins and callose.
Callose stains are aniline blue, resorcin blue and rosolic acid.
Abnormalities of the content and distribution of callose and phenolics are also mentioned.
Incompatible pollen is blocked initially by pectins followed by callose deposition.
Incompatible pollen tubes grow more slowly and, at least in some, the pollen tube bursts before it reaches the ovule and the polysaccharide callose is deposited around the tube.
Secondly, if pollen tubes entered into stigma, growth was retarded with callose plug deposition, then they stopped to grow because of inhibition.
Changes in the activities of CAT, SOD and the contents of H_2O_2, callose in cultivars of Stylosanthes spp differing in the disease resistance after inoculation with Colletotrichum gloeosporiodes;
A number of callose deposition can be observed in embryonic calli, but not in non-embryonic calli.
Random deposition of callose along pollen tube wall and even the whole wall was observed.
The self-pollinated pollen tubes stopped growing as the callose added on the cell wall.
Callose in the size of the spores in the period, a pattern of occurrence and degradation.
The abnormality of tetrad callose wall degradation and tapetum development was associated with the abortion of microspore.
Thick callose deposits in the walls of degenerative megaspores, while little in the wall of functional megaspore.
There was positive correlation between somatic embryogenesis and callose produced after plasmolysis treatment.
So there was no callose deposited at PD and viruses could transport between cells in the compatible combination.
In late development stage, they have callose wall, until the cells disintegrate.
At the stage of meiosis prophase, microspore mother cell begin to accumulate callose wall.
But the side walls usually lacked callose.
The accumulation of callose was benefit to dispersion of pollen mother cells and microspores.
The wall of the generative cell contains callose. Callose was absent at megasporocyte stage.
The formation of the callose wall occured at the PMC stage.
Therefore, the formation of callose in infected plants restrained water transport, and decreased leaf water content and photosynthesis.
Ovule development and callose deposition in Rheum palmatum
Callose exists mainly in transverse walls during dyad, triad and tetrad stages, a little in side walls.
It is suggested that the abnormality of callose wall and short of spro pollenin in the male sterile plant during the genesis and development of the microspore are the main reasons for abortion of microsporangium.
These phenomena may be related to the conveyance of implanted ions across cell wall, or be related to the accumulation of callose.
The results showed that pollen-wall protein can induce callose formation in stigma papilla cells with the same S-allele and self-compatibility in stigmas with different S-alleles;
No callose fluorescence shows in the wall of mononuclear embryo sac after its formation, while thick callose deposits in the wall of the degenerative megaspore.