چكيده انگليسي :
Safflower (Carthamus tinctorius L.) is an oilseed crop known for its adaptation to the climatic and edaphic conditions of Iran. It has the capability to grow and produce an acceptable grain yield under marginal soil conditions. It is tolerant to an array of environmental constraints, including drought and salinity. Zinc is involved in the synthesis of proteins and activity of many enzymes and plays role in the photosynthetic functions. Zn availability is not satisfactory, particularly in the saline and calcareous agricultural soils. Mycorrhiza increases the access of the plant root to the soil and hence enhances the absorption of soil water and minerals. Salt stress is a major constraint to the plant growth and productivity under the arid-semiarid climatic conditions. Symbiotic associations of plant-mycorrhiza improves the stress tolerance of the plants, but data on playing such roles in safflower grown under saline and calcareous soil conditions are scanty. Thus, safflower genotypes were exposed to either calcareous soil or saline water in the presence of foliar Zn application and soil mycorrhizal inoculation in two 3-replicates randomized complete block design pot experiments from March to July 2022 in the Isfahan University of Technology, Isfahan, Central Iran. One experiment sought to examine the genotypic (namely, Nebraska-10, Arak2811, Kordestan, and Kouseh) differences in response to Zn and mycorrhizae in a calcareous soil and the other one tested the effectiveness of Zn and mycorrhizae amendments in amelioration of moderate and severe salt stresses. Both Zn application and mycorrhizae inoculation enhanced traits such as 100-grains weight, grains/head, grain weight/plant, above-ground dry mass (SDM), leaf Zn, K, and P concentrations, root volume, dry weight, and cumulative length in all examined genotypes, but genotypes Kouseh and Arak2811 tended to outrank the remaining genotypes in terms of these traits particularly when amended with Zn and mycorrhizae. Salinity suppressed quantum efficiency of photosystem II (Fv/Fm), chlorophyll, carotenoids, Zn, P, and K concentrations, K/Na, relative water content, grains/head, heads/plant, grain weight/plant, SDM, and root volume, mycorrhization, dry weight and cumulative length, despite increasing carotenoids/chlorophyll concentration, proline, soluble carbohydrates, and Na concentrations. Though, both Zn and Mycorrhizae applications tended to mitigate the adverse effects of salinity through enhancing photosynthetic attributes (chlorophyll concentration and Fv/Fm), ionic balance (K/Na, P, Zn, and K status), water status (proline, soluble sugars, and relative water content), rooting (volume, length and dry weight) and consequently plant growth, grain weight, and SDM. The presented findings taken together, are suggestive of beneficial effects of foliar-applied Zn and mycorrhiza inoculation to the safflower’s physiological, growth, and grain yield attributes, particularly those of the genotypes Kouseh and Arak2811. Moreover, the above amendments lead to improvements in photosynthetic, growth, yield, and yield components of safflower under saline conditions, leading consequently to its salt tolerance.
Keywords: Safflower, Mycorrhizae, Zn, salinity, phosphorus, root volume, oilseed
