Cold-Induced Changes of Proline, Malondialdehyde and Chlorophyll in Spring Canola Cultivars

Abstractlow temperature (lt) is an important environmental factor that limits the survival, productivity and geographicaldistribution of plants. oil seeds are the second global food resources among which brassica napus l. is the third annualoil seed in the world. in cold stress, some biochemical and physiological reactions occur in response to reactive oxygenspecies (ros). hence, the quantitative changes of proline, malondialdehyde (mda) and chlorophyll (a, b, total) contentwere assessed in two spring canola (cv. zarfam, cold tolerant and cv. option 500, cold sensitive) seedlings exposed toearly spring cold stress. they were first grown in a controlled growth room at 22/16 °c (day/night) and then at the 4thfully expanded leafy stage seedlings were transferred to a cold environment (10/3 °c) for 7 d, or they were maintainedcontinuously at 22/16 °c (control). leaf samples were harvested at days 0 (transferred day), 2, 4 and 7 of cold exposureperiod. analysis of variance showed significant differences between the temperature treatments and also cultivars for allphysiological traits. the cold tolerant cultivar showed remarkable less lt-induced decrease in chlorophylls (a, b, total)and increase in mda and accumulation of proline compared to the cold sensitive cultivar. this assay verified thesuperior response of cold tolerant zarfam canola to cold temperature.