I did some pollinating today at about 7:00a.m. and it just now started raining at 4:00. So about 9 hours between the two. I am wondering if that gave the plants enough time to accept the pollen. Do you think it necessary to reapply tomorrow? The rain lasted only about 10 minutes and was steady but not too hard.
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You did this in daylight hrs, plants photosynthesis should have been working, should not be a problem. If you repollinate tomorrow, it will probably be more for your peace of mind.
I cover all my newly pollinated roses with âhatsâ I make out of blue paper shop towels. They make it through rain, hail and watering just fine.
Successful pollination requires the pollen to be hydrated by sugar-bearing phloem that exudes from the stigmata. Rain not only washes away pollen but also dilutes that exuded phloem thus limiting germination of pollen that doesnât wash off.
I try to protect pollinations from rain for 24 hours, and for 48 hours if phloem was not yet exuding from the stigmata when the pollination was made.
I write the pollen parent on masking tape and wrap the tape around the stem of the flower I just pollinated. This year Iâm taking another piece of tape and wrapping over the top of the flower to cover the stigmas. I havenât tried this before so I donât know how well itâll work. But Iâve had a lot of pollinations fail in the past from rain and I hope to get better hip and seed set this year by doing this. I just got done doing some pollinations and itâs about to rain now, it came up quicker than I was expecting.
Paul, are you thinking of also putting a second piece of tape, upside down so the two sticky sides adhere together so the sticky side of the tape doesnât pull the pollen off the stigma?
ThatââŹâ˘s a good idea Kim I hadnââŹâ˘t thought of doing that. I had concerns that the adhesive might pull the pollen off the stigmas if I moved or lifted the tape once it was applied so when I looped the tape over the top I did it in one quick motion without moving it. But putting a second piece of tape on first would be extra insurance of not disturbing the pollen.
ThatââŹâ˘s a good idea Kim I hadnââŹâ˘t thought of doing that. I had concerns that the adhesive might pull the pollen off the stigmas if I moved or lifted the tape once it was applied so when I looped the tape over the top I did it in one quick motion without moving it. But putting a second piece of tape on first would be extra insurance of not disturbing the pollen.
I use small draw-string bags made from organza over new pollinations for a few days to protect it from light-to-medium rain. It seems to do the trick nicely. My logic was that all I need do was intercept the rain and scatter the rain drop to reduce the impact. It reduces the amount of water on the stigmas too as it seems to wick/channel it away down to the draw-string region and then down the stem. It is primarily to keep insects away but it serves this purpose well too. I buy bags of 20 of them for $2 at the local $2 junk shop and have a stash of hundreds. It doesnât work on heavy rainâŚ
[center][attachment 740 drawstringbag.jpg][/center]
Simon,
That looked a little âfancyâ but the price is right, and they are perfect. And you can pull the strings to tighten, right? These are reusable, and at 10 cents per, are a bargain. Is the $2 junk store equivalent to the 99cents store here in the states? This seems so perfect for protecting against bees and other insects that might also âtamperâ with the pollen. If anyone knows a source stateside, please post.
Jackie, as I am in OZ as well and just read this bit, yes the $2 shop and the 99 cent are the same. Sometimes they are referred to as ârejectâ shops as well
Jackie, take a look at these. Organza or organdy is a good type to use as they would be a bit more water resistant than cotton while still breathing. I Googled âorganza tea bagsâ as those would be closest to the proper size. These clearanced ones are only eight cents each. Who cares what colors they are (except for very dark which may heat up too much) or whether they match or not? Iâd just specify any pastel colors or white when ordering.
Thank you Kim and Simon,
So I ordered 50 mocha (on clearance) colored covers, I only hope the roses feel as styling as they are gonna look.It is not so much about the rain as it is about insects, bees, and assorted vermin that may make things go wrong. There has been several good discussions about this very subject, and it always seems like such a good idea, but I just donât see myself making little âhatsâ-Iâm lucky to get both socks matching in the morning.
This is what I meant about protecting hips:
[attachment 748 2012newseedlings186.jpg]
This is supposed to be a Rt 66 X Basyes Legacy, but I believe both the color and the foliage is wrong, with new purple growth maturing to a shiny deep green. Right next to Rt 66 (over lapping foliage/branches) is a large Gemini. I have gotten yellow centered orangy reds from Gemini when crossed with Rt 66, and the foliage is identical to many Gemini seedlings. Bees love to visit Rt 66, even if I have a minimal amount of bees around, there is usually some action on newly opened Rt 66 flowers. A hip covering for 2-3 days would probably protect against this happening, and not to far from me a neighbor has started some bee hives, so I expect this more, not less.
[attachment 747 2012newseedlings189.jpg]
This red in real life is about as garish orange red as geranium red can get. But very showy. I have a couple of other less obvious but suspect seedlings, so I think that with the little âhatsâ in place, bees will have a harder time sabotaging.
Yup, makes perfect sense to me (whichever way you wanna cover 'em)!
Im still fairly new to rose breeding and i have to worry about rain all the time in south carolina and wanted to add to the conversation! I found this article on rose pollen tubes reaching the ovules between 12 and 24 hours post pollination
"## Pollen Grains and Tubesâ
Matteo Caser, in Reference Module in Life Sciences, 2017
Pollen Germination and Fertilization
Pollen tube growth in roses displays similarities to that in other Rosaceae and, by extension, other genera. When a rose pollen grain lands on a stigma, it adsorbs water and a rehydration process occurs. Various signals, especially those of pollenâstigma interaction, induce an intense metabolic activity in the pollen grain which start to grow and forms a pollen tube. The pollen tube invades the pistil, growing between the walls of the stigmatic cells, then traveling through an extracellular matrix within the transmitting tissue of the style. The pollen tube finally arrives at the ovary, where it is attracted to an ovule that contains an egg cell. This phase of pollen development, called the progamic phase, corresponds to the phase occurring between pollination and fertilization. In roses, the pollen tubes reach the ovules between 12 and 24 h after pollination. Fertilization is believed to occur within this interval of time. The growth of the pollen tube has been studied at the molecular level on model plants such as Arabidopsis thaliana, and several genes involved in pollen hydration, germination and tube guidance have been identified (Maruyama et al., 2014; Lin et al., 2014). The role of volatile molecules on pollination events are also described on the model plant Petunia x hybrida (Muhlemann et al., 2014). The primary pollination event is accompanied by an increase in ethylene evolution in the stigma and style within hours after pollination and well before pollen germination. While, among plant hormones, auxin is proposed to serve as the primary pollination signal by the direct transfer of pollen-borne auxin to the stigma (Kovaleva and Zakharova, 2003). Pollen tubes are themselves considered to be a model for cellular growth of plant cells.
Some external factors are well known to influence rose pollen germination strongly. Important variation in stigma pH can be found between genotypes. This factor, known to be involved in the pollen germination response, depends on the genotype, and plays a role in the fertilization response and consequently in seed set. Ionic elements, such as boron and calcium, that are involved in the metabolism during pollen tube growth, and at different concentrations can stimulate or inhibit it. Naturally occurring polyamines such as spermine also stimulate pollen tube germination and elongation when they are sprayed on the stigma. In vitro techniques for rose pollen germination are positively applied by using germination media containing boric acid (H3BO3), sucrose, putrescine, and agar at pH equal to 5.0. The fresh pollen is dusted directly onto sterile Petri dishes with the medium. Temperatures between 23â30°C and a relative humidity about 60â65% are the best conditions for in vitro pollen germination and pollen tube elongation. In hybrid tea roses the mean percentage of pollen germination is positively correlated with the percentage of normal pollen."
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Interesting! I make umbrellas with alumimium foil to keep the tubes dry and keep bees away. I sometimes keep them on for a week but maybe two days is enough.
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I do the same, but donât leave the aluminium foil umbrellas on the pollinated flower for a long time, max. 2-4 days. Experience has shown that too long air closure can also have a negative effect on a successful pollination. Moisture has built up and calyx, stigma and stamens became soft and light brown.