Yesterday afternoon, my husband and I went to check on our Chardonnay, which we know is the first to bloom and sure enough, the Chardonnay had just begun to bloom so we took some pictures. When we went home, I saw something in a few of my photos which gave me pause. It looked like a droplet of water on the top of the stigma on one of the flowers and then I saw it on another flower.
I recalled that I've blogged about this thing called stigmatic fluid in at least two of my posts:
Events Post Capfall and in
The Perilous Journey to Fruitset. Those blogposts contained these sentences:
"Rain can dilute the stigmatic fluid and interfere with germination of the pollen grains" and "the pollen grains adhere to substances secreted on the stigma". I understood from my reading that rain during flowering is a bad thing, but now I have the visual reason why this is so.
At first, I thought that I might have mistaken a drop of dew for stigmatic fluid, so today, my husband and I took more photos in the hopes of photographically capturing this elusive droplet called the stigmatic fluid. Once you know what it looks like, it's not as elusive as I originally thought.
In Nick Dokoozlian's chapter called
Grape Berry Growth and Development, which can be found online, he mentions that the stigmatic secretion consists primarily of sugars, proteins, and mineral nutrients essential for the subsequent development of the pollen tube.
1
So what happens if there is rain during flowering? We had that last year and it was not a pretty sight.
Yesterday, our Chardonnay was probably at the beginning stages of flowering and today, it is probably at more than 50% flowering. Fortunately for us, the grape flowers, and the elusive but important stigmatic fluid, we are in for a stretch of days with no rain.
References:
1. Nick K. Dokoozlian,
Grape Berry Growth and Development.
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