Scottish Rock Garden Club Forum

Bulbs => Galanthus => Topic started by: annew on January 29, 2014, 06:47:51 PM

Title: Snowdrop pollination - brainstorming needed
Post by: annew on January 29, 2014, 06:47:51 PM
The problem - some of the snowdrops I want to pollinate are in my frames in baskets, and so can't be lifted to bring into the warm to get the pollen running etc. Any ideas about how to raise the temperature just over single pots to a) get the pollen running and
b) allow the donated pollen to germinate and grow down the pollen tube for fertilisation?
Also does anyone know how long it takes for the pollen tube to reach the ovary? In fact is there a minimum temperature at which this occurs? Bearing in mind the prevailing weather at the normal time of flowering of snowdrops, maybe it will happen even at low temperatures?
Next year, I must try and get potential parents into the greenhouse to make it easier (and save my knees). Next problem, how to make more space under glass??
Title: Re: Snowdrop pollination - brainstorming needed
Post by: Tim Ingram on January 29, 2014, 06:53:47 PM
Anne - would those heated pads sometimes used to reduce back pain work? You'd probably have to rig up a clamp to hold them in place (and maybe enclose the snowdrops in a prop. box if that would work?).
Title: Re: Snowdrop pollination - brainstorming needed
Post by: annew on January 29, 2014, 06:57:48 PM
They'd certainly help my knees!!
Current suggestion from husband is bottomless lemonade bottle to make tall mini-propagators. Maybe some sort of light bulb to provide heat?? The question is really how long would these need to be in place to have the desired effect? Even half an hour would probably get the pollen running, but it's the actual fertilisation that I'm completely in the dark about. 8)
Title: Re: Snowdrop pollination - brainstorming needed
Post by: Maggi Young on January 29, 2014, 07:07:54 PM
Margaret Taylor taught  the trick  at shows of covering a plant with an upturned bowl  - warmed by filling with hot water then emptied  and upturned over the plant for a few moments to encourage buds to open with the  resulting warm humid atmosphere .  Perhaps an old glass cloche ( if made of thick enough glass) or a large plastic container would work over larger plants.  Pyrex ( unbreakable glass) bowl or jug would do the trick.

 Better to be glass or something transparent so you can easily follow the progress of the opening flower.
Worth a try?
Title: Re: Snowdrop pollination - brainstorming needed
Post by: annew on January 29, 2014, 07:09:59 PM
Sounds like the knees are in for a long haul....
Title: Re: Snowdrop pollination - brainstorming needed
Post by: ichristie on January 29, 2014, 07:52:03 PM
Hello Anne, I can see you have a few problems to pollinate the snowdrops I have often wondered and asked many questions just how long the pollen is viable and when we have wild colonies with two different species G. nivalis which are usually late and G plicatus where some are early and some are late like the ones at Brechin the resulting hybrids can flower around end of January whilst nothing else is anywhere near also the hybrids between the two species some look like G, nivalis produce a twin flower spike and leaves that are folded on one side. I will post some pictures just to show this.
Title: Re: Snowdrop pollination - brainstorming needed
Post by: annew on January 29, 2014, 10:50:18 PM
You are clearly getting some overlap in the flowering period, Ian.
Title: Re: Snowdrop pollination - brainstorming needed
Post by: hwscot on January 29, 2014, 11:30:55 PM
The reusable heat pads are chunky enough they'd be quite easy to prop up beside the plants, I would think. They stay warm about an hour. We get them from Lidl, couiple of quid a packet of two. Invaluable for back ache and may be adaptable for knees. Simmer for ten minutes to reset - pads, not knees.
Title: Re: Snowdrop pollination - brainstorming needed
Post by: Margaret on January 29, 2014, 11:50:16 PM

Have you tried knee pads, Anne. They help a bit.
Title: Re: Snowdrop pollination - brainstorming needed
Post by: annew on January 30, 2014, 08:29:41 AM
I do have a very good memory foam kneeling pad, it's just the last couple of weeks I've been redecorating and un-flatpacking furniture so they've been hammered more than usual! I also have some gel packs which I keep in the freezer for headaches/muscle problems, but they can be used as heat pads by microwaving them, so they would probably do the trick for heating the flower to get pollen.
Still don't have any info on speed of growth of the pollen tube down the style, or minimum temperature at which this happens. Given the time of year they flower, can we assume the pollen will germinate and grow at 'normal' January temperatures, do you think?
Title: Re: Snowdrop pollination - brainstorming needed
Post by: Alan_b on January 30, 2014, 11:26:49 AM
I would guess that if it's warm enough for the bees to come out then it's warm enough for germination.  That's probably just a few hours on a few days in January.
Title: Re: Snowdrop pollination - brainstorming needed
Post by: mark smyth on January 31, 2014, 01:11:22 PM
Easy - grow some pots in your sand plunge then bring them in for a few hours
Title: Re: Snowdrop pollination - brainstorming needed
Post by: Maggi Young on January 31, 2014, 01:18:19 PM
Easy - grow some pots in your sand plunge then bring them in for a few hours
No it's not that easy - such plants will have roots going out into the plunge and it will damage them to lift them .  I think Anne already mentioned that. 
It 's for that reason that Ian doesn't lift pots even from  from the glasshouse plunge for photographs.
Title: Re: Snowdrop pollination - brainstorming needed
Post by: Garry Edwards on January 31, 2014, 01:56:02 PM
Depending on the size of cold frame and its construction ,hang 4ft twin strip lights with 30 watt tubes,then cover frame with a layer of frost blanket or similar product then finish of with poly to keep blanket dry. 4ft of strip light per 6 ft frame approx.I have tried different types of bulbs it does not seem to matter which ones you use.

The lights are not there to help the plant growth but to provide a warming effect for the bench.

During the day the frost blanket is removed as soon as the sun is up or the temperature has risen in the tunnel,if the temperature does not increase in the tunnel the frost blanket remains in place with no adverse effects on the plant material.

This should raise the temperature by at least 6-10 degrees.

I am using this system on a raised bench 48ft x 4ft with multiple lights with a layer of poly then three layers of heavy duty frost blanket inside a double skinned unheated poly tunnel. The outside temp can drop to minus 20 and the bench will hold a temp of  plus 10 to 12 depending on the wind chill factor.

The bench also has soil warming cables installed which are on a thermostat set at 7 degrees, this only seems to come on when the temp drops below -25 outside  and because the bench is well insulated they do not run for very long. 
Title: Re: Snowdrop pollination - brainstorming needed
Post by: mark smyth on February 04, 2014, 11:14:30 AM
I lift snowdrops, grown in clay pots in the sand plunge, to bring them inside to warm up to photograph. I rarely find more than a few roots out of the bottom hole. This one I just lifted
Title: Re: Snowdrop pollination - brainstorming needed
Post by: annew on February 04, 2014, 05:58:30 PM
I am lifting pots where possible, it's the ones in baskets I'm having problems with. Garry, that sounds like an excellent solution, but probable rather more than I need here - we're not as cold as you. Had some luck over the last few days with a bit of sunshine to heat the frames - I've pollinated and then partly closed the frames to retain the warmth. I've reapplied the pollen on the more important ones on subsequent days as well. Hope it works!
Title: Re: Snowdrop pollination - brainstorming needed
Post by: Matt T on February 04, 2014, 06:38:37 PM
I think I read somewhere that EA Bowles would hold a bell cloche over a flame to capture warm air and then place it over a Crocus to encourage the flowers to open and allow pollination. A similar arrangement might work for you with the bottomless lemonade bottle and a suitable heat source?

In terms of fertilisation, it appears there are several factors involved - pollen adhesion, pollen germination, pollen tube growth, ovule receptivity etc. There seems to have been a lot of research on this in fruit trees (peaches, cherries etc).

Some studies have found that temperature can affect different part of the fertilisation process, i.e. increasing temperature speeds up pollen germination and pollen tube growth in peaches, but reduces stigmatic receptivity (http://www.ncbi.nlm.nih.gov/pubmed/16163612 (http://www.ncbi.nlm.nih.gov/pubmed/16163612)).

In cherries pollen germination was inhibited by increasing temperature but not pollen tube growth and the number of pollen tubes reaching the base of the style remained constant across a range of temperature regimes (http://www.amjbot.org/content/91/4/558.full (http://www.amjbot.org/content/91/4/558.full) - this paper cites some sources that look like interesting further reading).

Genetics also appear to have an effect on pollen germination and tube growth (www.researchgate.net/publication/222331537_The_effects_of_temperature_on_in_vitro_pollen_germination_and_pollen_tube_growth_of_Pistacia_spp (http://www.researchgate.net/publication/222331537_The_effects_of_temperature_on_in_vitro_pollen_germination_and_pollen_tube_growth_of_Pistacia_spp)).

Here is a paper on Erythronium grandiflorum, which found that "The number of pollen tubes reaching the base of the style increased rapidly between 24 and 72 hr after pollination and few or no pollen tubes grew to the ovary after 72 hr". It is also suggested that pollen tube growth is inhibited more in self-pollination than when outcrossing. (http://labs.eeb.utoronto.ca/thomson/publications/Referreed%20Article%20from%20Lab%20Group/Cruzan%20Pollen-tube%20attrition%201989%20Am%20J%20Bot.pdf (http://labs.eeb.utoronto.ca/thomson/publications/Referreed%20Article%20from%20Lab%20Group/Cruzan%20Pollen-tube%20attrition%201989%20Am%20J%20Bot.pdf))

These are not Galanthus I know, but they demonstrate that successful fertilisation of the ovules might not be a simple linear relationship with increasing temperature?

If I were you, I'd just go for it and assume that as the plants are now flowering, temperatures must also be sufficient to allow fertilisation of (at least some of) the ovules.

Good luck!
Title: Re: Snowdrop pollination - brainstorming needed
Post by: annew on February 05, 2014, 05:39:59 PM
Thanks for those, Matt. I'll just plod on and see what happens. :)
Title: Re: Snowdrop pollination - brainstorming needed
Post by: hwscot on February 27, 2014, 04:15:54 PM
Being new to pollinating snowdrops, I appreciate all the practical advice. Thanks to Anne's (soundtrack deleted) video, and with the help of this thread, I have found collecting pollen much easier than I expected.

Title: Re: Snowdrop pollination - brainstorming needed
Post by: annew on February 27, 2014, 06:22:27 PM
 ;D ;D