Putrescine helps pollen germination

I have come across articles like this before but have not posted them as I figured that amateur hybridizers would not have access to / or want to work with putrescine; but I think that some of the posters lately appear to be rather sophisticated so maybe there would be an interest.

Title: Effects of putrescine application on fruit set in Housui’ Japanese pear (Pyrus pyrifolia Nakai).

Authors: Franco-Mora, O.; Tanabe, K.; Tamura, F.; Itai, A.

Authors affiliation: Laboratory of Horticulture, Faculty of Agriculture, Tottori University, Koyama Minami 4-101, Tottori, Japan.

Published in: Scientia Horticulturae (Amsterdam, Netherlands) (2005), 104(3), pages 265-273.

Abstract: “In Japan, artificial pollination is practiced to improve fruit set as well as fruit size and to obtain perfect round shapes in Housui’ (S3S5) Japanese pear and most com. cultivars that present gametophytic self-incompatibility. The period of artificial pollination application is limited by environmental conditions and the availability of a labor force. The present study aimed to det. if pre-pollination applications of putrescine (1.0 and 0.01 mM) pos. affect fruit set in Housui’ after hand-pollination. During 2002 and 2003, fruit set in late pollinated flowers increased with pre-pollination putrescine applications and concns. of 1.0 mM had a better effect than 0.01 mM. In vitro pollination tests revealed that higher pollen germination was present in the stigmas of flowers sprayed with 1.0 mM of putrescine compared to the controls. Putrescine application did not affect post-pollination ethylene prodn. in the styles. Moreover, in the styles of non-treated flowers, an increment of putrescine content and ethylene prodn. after pollination was found, suggesting post-pollination responses and confirming the lack of antagonism between polyamines and ethylene at least during this process.”

Here’s a reference I’ve come across in Hort Tech that specifically addresses roses.

Gudin, S. and Ar

I wonder if the amine component of many 2 component expoxies would work also.