problems with growing healthy Arabidopsis plants

Hello

I’m writing to see if anyone has come across these types of problems with
growing of Arabidopsis plants and knows the reasons for these problems.



We grow Arabidopsis plants in two ways. For some experiments they are grown
in trays with 36 slots filled with soil-less mixes such as Pro-mix (Plant
Products) or Sunshine mix (JVK). For other experiments plants are grown in
individual pots ranging in size from 2.25” to 4”. Plants in trays are
usually grown in reach-in two shelf growth chambers (MTR30, Conviron) and
plants in individual pots are grown in walk-in chambers (PGV36, Conviron).
All chamber have the same growth conditions of 22C, 50-70% RH, 18hr light
(150-200 uE) and 6hr dark. Plants are watered with RO water daily from the
top as needed, trying not to over-water and allowing soil to dry up a little
between waterings, especially when the plants get a little bigger . All
plants are fertilized twice weekly with 20-20-20 (plant products) (1g/L)
solution starting at about 1 week after transplant. All plants are started
on ½ MS agar plates for 1 week before transplanting into soil media.



Only in plants that are grown in the walk-in chambers (in individual pots
rather than trays) we see the following 2 problems:



1). During vegetative growth at about 4-5 leaf stage the main meristem dies
off, senesces and stops further production of leaves. These plants do not
bolt or continue to grow.



2) Plants grow nicely until bolting time. At bolting the main stem
produces sick abnormal flower. The buds are very small and open into tiny
flowers which become aborted and do not result in no healthy pod production.
Sometimes, healthy flowers and pods will form after a series of abnormal
flowers and sometimes not.



These two problems can happen independently or in the same experiment.



We have noticed these problems on and off over the last few years.
Generally, more so in the winter than in the summer. We have attributed
them to problems with soil because changing our soil mix from Promix to
Sunshine or vice versa would generally get rid of the problem. Recently,
however both soil mixes give us these problems. The puzzling thing is that
plants grown in trays in the smaller reach-in chambers do not show any of
these problems and the same soil media are being used.



I would welcome any suggestions or ideas on what may be at the root of the
problems



Monika Kuzma







Dr. Monika Kuzma

Manager, Gene and Trait Assessment



Performance Plants Inc.,

4th Floor, BioScience Complex,

116 Barrie Street, Suite 4600

Kingston, ON K7L 3N6

Telephone: (613) 545-0390 EXT. 18

Facsimile: (613) 545-3618

Email: [Only registered users see links. ]

Web: [Only registered users see links. ]



the promise of growth



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Dear Dr. Kuzma,

I read your note about growing healthy Arabidopsis plants. I have a
few suggestions.

You may be fertilizing the plants too much. I would suggest either no
fertilizer if your soil mix already has fertilizer amendments, or use
of half-strength Hoagland's solution once every one or two weeks (in
addition to watering when necessary).

In addition, top watering is a nuisance for the plant caretaker and is
also hard on the plants; sub-irrigation is much easier on both. The
flat that holds the pots can be filled to about 5 cm water, and in 10
minutes, the soil will absorb as much water as it will hold. Then
decant the excess liquid to prevent waterlogging the soil (which
stresses the plants and can lead to disease problems). When the pots
start to feel lighter in weight, then is a good time to water (usually
every 3-4 days).

You might also check to be sure that the temperature is not over 22°C,
as at higher temps the plants have poor pollen (and thus seed and
silique) set. Also, if plants in growth chambers are grown over
fluorescent lamp fixtures from the shelf below, the bulbs can heat up
the soil and stress the plants, even if the air temp is cooler.

Good luck!

Terry Delaney

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Terrence P. Delaney, Ph. D.
The University of Vermont
Department of Plant Biology
326A Marsh Life Science Building
Burlington, VT 05405-0086
Phone: (802) 656-0416; Fax: (802) 656-0440
E-mail: [Only registered users see links. ]
Lab website: [Only registered users see links. ]
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On Feb 6, 3:47 pm, "Monika Kuzma" <[Only registered users see links. ]>
wrote: