The pitaya pollen information was summarized from following scientific references.
1. Metz C., A. Nerd and Y. Mizrahi. 2000 Viability of pollen of two fruit crop cacti of the genus Hylocereus is affect by temperature and duration of storage. Hortscience 35：199-201
2. Weiss J., A. Nerd and Y. Mizrahi. 1994 Flowering behavior and pollination requirements in climbing cacti with fruit crop potential. Hortscience 29（12）：1487-1492
Pollen morphology (Yi-Lu unpublished data)
1. Pitaya pollen grains was spheroidal with 3-colporate.
2. Pollen tectum is perfotate and Pyramidal/spinulose.
(Left : Selenicereus megalanthus Right: Hylocereus sp.)
(Left : Selenicereus megalanthus Right: Hylocereus sp.)
Pollen viability and germination (Weiss et al. 1994)
1. Viability of fresh pollen (taken at flower opening) was high, 90% - 94% (was tested by fluorochromatic assay) in Hylocereus spp and about 1/3 of it in yellow pitaya.
2. Pollen was sampled at 12 h intervals from flower opening and ending 72 h later. Pollen germination (in vitro) was highest at started to open (about 60%), declined following evening (about 50%) and declined to 0% after 60 h in Hylocereus undatus (clone A).
3. Pollen germination was effect by plant species, cultural medium composition, and incubation temperature. For example, Pollen germination (in vitro) was declined to 0% after flower opening 36 h in Hylocereus undatus. (Cheng, 1999)
Effect pollination period (Weiss et al. 1994), Pollen tube growth (Yi-Lu unpublished data)
1. Pollination after flower opening 0 – 24 h, 36 h, 48 h fruit set was 100%, 38% and 0% respectively in Hylocereus polyrhizus. The fruit weight was declined according to pollination timing.
2. After 42-48h Pollination, pollen tube growth into ovary in Hylocereus undatus (observation by Fluorescence Microscopy).
Pollen long-term storage (Weiss et al. 1994, Metz et al. 2000)
1 Semi-climbing cactus pollen belongs to trinucleate and with 3-colporate. In general, this type was short storage life.
2 For breeding purpose was to develop a method to long-term storage pitaya (H. undatus) pollen.
2.1 First, collect fresh pollen at flower opening (moisture content was 45-50%).
2.2 Second, pollen dehydration with vacuum desiccator (-50kpa) at room temperature until moisture content has been reduced to 5%-10%.
2.3 Third, dehydration pollen was storage in +4, -18, -70 and -196℃ for 3 and 9 months.
2.4 Fourth, flower pollinated by dehydrated pollen to assay fruit set percentage, fruit weight, and seed number.
2.5 Result :
2.5.1 Generally, pollen stored at 4℃ fruit set only 60-70%, yielded smaller fruit (about 240-290g), and with less seed number per fruit (average 2538).
2.5.2 Pollen stored at -18 to -196℃ fruit set was 100%, yielded bigger fruit (about 390-490g), and with more seed number per fruit (average 5014 to 6067). The seed number per fruit was 5988 in control fruit (pollenated with fresh pollen).
I don’t collect any information about short-term storage of pitaya pollen. I beg, if anyone knows about this respect information. Please let us know.