*4.4. Plant Materials, Growth Conditions and Stress Treatments*

Seeds of *Arabidopsis thaliana* ecotype Columbia (Col-0) were used in this research. The seeds were surface sterilized with bleach and washed extensively with sterilized water for three times, and then incubated in a growth chamber after cold treatment for two days. After growth for one week, the seedlings were exposed to various stress conditions in plates containing 150 mM NaCl and 10 µM ABA, respectively. For cold and heat treatment, 7-day-old plants were placed at 4 ◦C or 42 ◦C incubator with normal illumination. Samples from leaves, buds, flowers and siliques were collected from well-growing plants at the same time. All the plant materials were harvested by liquid nitrogen cooling before stored at −80 ◦C.
