Seed vigor and ion toxicity in safflower (Carthamus tinctorius L.) seedlings produced by various seed sizes under NaCl stress

Abstract

Safflower is an important oilseed crop and is largely grown for edible oil production in low moisture or saltaffected soils of Turkey. The objective of the study was to find out the quality of seeds with different sized seeds, and the effects of seed size (3, 4 and 5 mm) and NaCl stresses at electrical conductivities of 5, 10, 20 and 30 dS m-1 on the germination and early seedling growth of the safflower cultivar Dinзer. Our results show that heavier one-thousand-seed weight (70.5 g) and higher hull percentage (52.9 %) were obtained from large seeds while the oil content and water uptake of small seeds was higher than that of medium or large seeds. Germination percentage, germination time, root length, shoot length, and seedling fresh and dry weight showed size-dependent responses of the seeds to salt stress. In general, medium-sized (4 mm) seeds germinated more rapidly compared to small and large seeds against all levels of salt stress; however, the highest germination percentage and most vigorous seedling growth was recorded from large seeds after 10 days incubation. The inhibitory effect of NaCl levels was exhibited a drastic effect on seedling growth. Increased NaCl resulted in an increase in the Na+ and Cl- content of the seedlings produced by all seed sizes, while the K+ content was not changed. However, the seedlings from small seeds had the highest Na+ and Cl- content of all measured NaCl levels. It was concluded that large seeds produced vigorous seedling growth due to a lower ion accumulation under NaCl stress. Consequently, large seeds could be used for successful stand establishment in contrast to their slow germination performance if the cultivation of safflower on saline soils is required

Salt and drought stresses in safflower: a review

“…Sodium and sulfate stimulated sulfate uptake, which reflects that plants have the ability to maintain sulfate uptake under saline conditions (Patil 2012). Increased NaCl resulted in an increase in the Na + and Cl − content of the seedlings, while the K + content was not affected and large size seeds produced vigorous seedling growth due to a lower ion accumulation under NaCl stress (Kaya et al 2011). …”

“…Na + is the principal toxic ion, which interferes with potassium uptake and transport in safflower leading to disturbance in stomatal modulations and causing water loss and necrosis (Siddiqi et al 2011). Competition between potassium and sodium under salt stress severely reduces potassium content in both leaves and roots of safflower (Kaya et al 2011). The uptake of phosphate and its accumulation is reduced in crops due to salt stress due to the reduced availability of phosphate in salt-affected soils (Ashraf 2004 , and N was decreased with increase in salt stress (Jamil et al 2006) and Ca 2+ displaces Na + from the plasmalemma of salt-stressed root cell, thus decreasing the influx of ions into the cytoplasm (Lynch et al 1987).…”

Calcium and magnesium do not alleviate the toxic effect of sodium on the emergence and initial growth of castor, cotton, and safflower

“…The safflower line 672 apparently had no ion-specific mechanism because the response was explained by the EC of water rather than the salt composition. The tolerance found in some safflower cultivars was attributed to combinations at varying degrees of several physiological mechanisms such as ion-exclusion, osmotic adjustment, accumulation in the vacuole, production of anti-oxidant substances, and ion-tolerance (Kaya et al, 2011;Karray-Bouraoui et al, 2011;Siddiqi et al, 2007Siddiqi et al, , 2011Siddiqi and Ashraf, 2008).…”

“…Similar to what was discussed for cotton, traits associated with salt tolerance in safflower have high heritability (Golkar, 2011), and the tolerance is specific to the conditions that the plant was selected, particularly regarding ion composition. Thus, safflower is regarded as a salt tolerant species, but there is large variability among varieties in this characteristic (Bassil and Kaffka, 2002;Golkar, 2011;Irving et al, 1988;Karray-Bouraoui et al, 2011;Kaya et al, 2011;Siddiqi et al, 2011;Yeilaghi et al, 2012). The line 672 used in this study was not selected under salt stress (but to endure low temperatures during winter), and consequently it showed little tolerance to this stressful condition.…”

Dimension, Geometric, Agricultural and Quality Characteristics of Safflower Seeds

“…Researchers (Sadeghi et al, 2011;Kaya et al, 2011) put forth interesting results about the relationship between dimension and seed germination properties. Therefore, the best way to know the properties of safflower seeds has multiple benefits.…”