Picture taken from http://www.steve.gb.com/science/plant_growth.html
Two days into the research rotation and I’m already really enjoying the work. Alan gave me a shot right away at meristem isolation on chrysanthemums, an incredibly intriguing and patience-teaching process. I wish I could put a picture I took up here to demonstrate, but I don’t have the tools to take photos through a microscope. Thus, I’ll just have to paint the picture with words (and steal an illustration from another website).
First off, the reason for meristem isolations is to enable virus-free propagation. For instance, I am working with chrysanthemums that have had a virus, but getting new plants of these varieties is not possible due to international restrictions on the ones that came from abroad and other various reasons. As such, if Longwood wants to continue using these varieties in their mums display each autumn, the plants must be propagated in a way that rids them of the virus. A meristem is the growing point where cells begin differentiating to form leaves. As such, the virus hasn’t infiltrated it yet. Under the microscope, a meristem just looks like a perfect sphere of green jelly.
To perform a meristem isolation, I begin with about a two inch cutting of the apical tip (end of a stem where leaves are emerging). In a sterile chamber under a hood that removes any contaminated air, I then use a microscope to carefully cut away the tiny leaves that are just beginning to form, peeling them away like the way you peel an onion. Slowly, the inside of the stem emerges, along with all the “hair” that surrounds the meristem of mums. Under increased magnification, I have to carefully scrap away the hairs, a very tedious process, until the top of the meristem appears like a glowing little orb. Next comes the trickiest step: I have to hold my breath and make very finite cuts with the tip of the scalpel to shave out a “pedestal” under the meristem so that I can then pop it off without bursting it. After the meristem is on the tip of my scalpel, I then place it in a tube with augur and hope that it grows into a new virus-free plant.
What’s really shocking about this process and what I wish I could picture is how tiny this little blob is. The first time I did it, I was very focused on my work under the microscope and didn’t bother to look at anything out from under it until the end. What had looked so important and noticeable under magnification was just the teeny tiniest speck on the end of my scalpel that I really wouldn’t have seen if I hadn’t known to squint hard and look for it. I can’t believe I could find the thing, let alone isolate it and pick it up! Apparently this ability is a bit of a talent as Alan says not everyone gets it, let alone on their first try. Yah for me, I guess. All I know is I really enjoy performing meristem isolation, and I think I might get lots of practice at it this month, judging from the gleem in Alan’s eye
