توصيفگر ها :
تغيير اقليم , تنوع ژنتيكي , خشكسالي , درصد روغن , شاخص تحمل به تنش , گلرنگ , دي اكسيدكربن
چكيده انگليسي :
Nowadays, the effects of climate change, population growth, and industrial development may lead to a decline in the share of water resources to the agricultural sector and an increase in water scarcity related to crop production in arid and semi-arid regions. Furthermore, the rise in the concentration of atmospheric carbon dioxide, the primary greenhouse gas, has affected the plant's growth. Meanwhile, the safflower plant (Carthamus tinctorius L.) should be more considered in crop rotation under these harsh conditions because of its adaptability to water shortage conditions, great-quality seed oils, high added value in picking petals, the possibility of planting in different seasons, and the ability to provide proper fodder for animal husbandry units. Therefore, this research was conducted to study the interaction effects of both CO2 concentration and soil water levels on growth and some physiological traits of safflower plants under Open Top Chambers (OTC) conditions during spring 2021 at Bagh-e-Anari Research Field Station (32◦42′ N and 51◦32′ E; altitude of 1,645 m above sea level) of Isfahan University of Technology, Isfahan, Iran. Four safflower genotypes including Arak, C411, Koseh, and PI-301055 were grown under three irrigation regimes (based on 50%, 75%, and 85% soil-water depletion as control, mild, and severe water deficit levels, respectively) as a factorial experiment in a randomized complete block design with three replications at two atmospheric CO2 conditions (400 ± 50 and 700 ± 50 μmol mol-1 as ambient and elevated conditions). The results showed that under ambient CO2, mild water deficit stress reduced shoot dry weights (ShDW) of Arak and Koseh genotypes by 17 and 19%, respectively, however it had no significant effect on C411 and PI genotypes. Moreover, severe water stress decreased the ShDW of all genotypes. While, under elevated CO2, mild water deficit stress just deteriorated ShDW of C411 genotype (about 30%). Unlikely, severe water stress decreased the ShDW of all genotypes. In addition, elevated CO2 just enhanced the Arak genotype's root dry weight and not affected others. Plant Seed weights averagely declined due to mild and severe water stress by 27 and 54 %, respectively, compared to the control treatment, and the highest and lowest ones belonged to Koseh (0.909 g plant-1) and PI (0.729 g plant-1) genotypes. Under elevated CO2, mild water deficit stress just reduced the petal weight of the C411 genotype (about 48%) and had no significant effect on others, while severe water stress decreased petal weights of all ones. Enriched CO2 condition led to an increase in the irrigation water use efficiency (IWUE) of Arak, Koseh, C411, and PI genotypes by 18, 39, 34, and 25%, respectively, and on the contrary, seed oil concentration decreased by 17, 29, 8 and 23%, respectively. According to the biplot curve, the highest values of seed oils and root volume were observed in C411, while the highest of Fv/Fm was considered in PI genotypes, under combined elevated CO2 and severe water deficit stress conditions. However, maximum levels of shoot dry weight and IWUE were found in Arak and Koseh genotypes. Commonly, it can be stated that safflower plants' growth response to different CO2× Soil water status conditions was genotype-dependent. Moreover, the attributions of studied traits regarded to the quantitative and qualitative plant growth were altered depending on the growth conditions, which should be considered in its breeding programs.
