جستجوی مقالات مرتبط با کلیدواژه « عدد spad » در نشریات گروه « زراعت »

The aim of this study was to investigate the sole and combined effects of drought and salinity stresses on some physiological characters of two canola varieties in Ahvaz as outdoor pot experiment. This factorial experiment was based on randomized complete block design. Results showed that both salinity and drought stresses decreased seed yield, shoot dry weight, root dry weight, harvest index, biological yield, plant height, number of branches per plant and relative water content of leaf (RWC). Drought and salinity stresses increased SPAD value and relative membrance permeability (RMP). However, combined stress had a greater effect on these parameters than each sole stress. In the salinity stress, a significant positive correlation was observed between relative membrance permeability and shoot dry weight (r= -0.93**). Also, a significant negative correlation was found between relative membrance permeability and relative water content in combined stress (r= -0.94**). Relative water content was reduced because of damage to the membranes and increase of electrolytes leakage. Generally, Hyola401 variety exhibited better defensive mechanisms and more efficiency than Shirale in maintaing relative water content and relative membrance permeability in salinity, drought and combined stresses. The study showed that Hyola401 was more tolerant than Shirale under salinity, drought and combined stresses.

To study of salicylic acid effect on chlorophyll fluorescence parameters under salt stress condition an experiment was conducted in Split factorial based on randomized complete block design with three replications at Shahid Chamran University of Ahwaz research farm. In 4-leaf stage after full expanded leaves, simultaneous with 150 mM NaCl salt stress applying; the leaves of salicylic acid including 0, 0.5 and 1 mM was sprayed on the leaves early morning. Two cultivars (Jolge and Sharif) of sugar beet were used at this experiment. Growth analysis was done at vegetative stage and ripening. Salinity caused significant reduction in root and shoot dry weight, stomatal conductance, SPAD value,Ф PSІІ, qP and Fv/Fm. Also salt stress resulted in significant increase in NPQ. Treatment by salicylic acid caused significant increase of root dry weight, stomatal conductance conditions stress, SPAD value,Ф PSІІ, qP and Fv/Fm compared to not application of salicylic acid under salt stress conditions. According to the results of the Correlation, photochemical quenching excited electron energy (qP) and root dry weight (r = 0.56*) and shoot dry weight (r = 0.68**) stress conditions showed a significant positive correlation. Therefore this attribute can be used to screen for these cultivars under the conditions foliar salicylic acid.