Preserving pollen.

Dr Roland Fischer comments:-

A limiting condition in breeding is the fact that open flowers of
different species are often unavailable at the same time. Many species flower at different times of the year; e.g., P. actinia mainly in spring, P. phoenicea on the other hand mainly in late summer. Many species flower for a short period only but in batches of up to 20 flowers at the same time; e.g., P. retipetala. Even banal reasons, eg., the different age of individual plants, can bring about a situation in which the potential pollinator is in full bloom while the potential partner is just setting small flower buds. One possibility to pollinate a flower successfully is the preservation of pollen that is to be used later. The following procedure is to be recommended.

 1. After the flower has opened one waits until the anthers have burst completely and have released the mature pollen. The pollen is cautiously removed with a fine brush and put on a clean, white sheet of paper. The pollen from several flowers of the same plant can be put in one place.

 2. The paper with the fresh pollen is taken to a moderately warm place where the pollen can dry swiftly but gently. There are many places in an apartment which are suited for that. The place should be warm, but not too hot and the atmospheric humidity should be very low. Suitable is a location near a fluorescent lamp or a heater. If there is no place to secure sufficient drying, the paper with the pollen can be stored on a little bag with a desiccant (available in computer shops) in a tight fitting vessel, e.g. in a jam jar. When this vessel is stored in a warm place the pollen will dry very rapidly.

 3. The paper with the dry pollen is folded and labeled with the pertinent annotations: date, name of the plant, clone number, etc. Put on a fresh desiccant bag in a tight fitting vessel it is stored in the fridge at a temperature of 4°C (40°F).

 4. As soon as the flower that is to be treated is ready for pollination, i.e. when the styles begin to bend down, the paper with the pollen is opened and the dry pollen is spread onto the fresh stigma with a fine brush. Then the atmospheric humidity is raised. However, the pollinated stigmas should not be sprayed directly.

 There is no systematic investigation regarding the usability of stored passionflower pollen. Chinese authors report that pollen of magnolias had a vitality of 50% after it had been stored on a desiccant for a month. (JINGMIN et al. 1999).