BRASSICA NAPUS L واكنش اجزاي جوانه زني بذر به تنش شوري در كلزا

Response of Germination Components to Salinity Stress in Oilseed Rape (Brassica napus L.)

Germination rate (GR), final germination percentage (FGP), germination uniformity (GU) and heterotrophic seedling growth are important components in the germination process in crops. It is likely that sensitivity of these components varies according to environmental stresses, including salinity. Furthermore, for breeding purposes and in order to increase salinity resistance in germination stage, knowledge of relative sensitivity of germination components as well as identification of the most sensitive component is necessary. Hence, this study was conducted to examine the responses and relative sensitivity of germination components of oilseed rape (Brassica napus L.) to salinity. The experiment was conducted in petri - dishes using a factorial arrangment in a completely randomized design with 5 replications. Experimental factors were NaCl salinity at three levels (0, -0.4 and -0.8 MPa) and a number of five oilseed rape cultivars (Talaie, Ceres, Regent, Cobrax W. A and PF 7045.91). Results showed that salinity has a significant effect on Gr, GU, FGP as well as seedling length and root 1 shoot ratio (R: S), but these components were affected by varying degrees. FGP and GR were the most tolerant and sensitive components, respectively. Root growth was more sensitive than shoot growth. Also, significant cultivars x salinity interactions were found for GR, FGP and GU, but not in the case of seedling growth. In control, the highest GR (0.58) was observed for Ceres, while the lowest decrease in GR, relative to control (19.6%), in high salinity treatment (-0.8 MPa) was observed for Regent. The lowest decline in GR relative to control in medium salinity (-0.4 MPa) was observed for the case of PF 7045.91.