Effect of Different Levels of Zeolite on some Physiological Traits, Oil and Protein Yield of Linseed under Deficit Irrigation

Abstract
In order to investigate the effect of different levels of zeolite and defficit irrigation on some physiological traits, oil and protein yield of lineeed crop, in a split plot experiment were conducted in based on a randomized complete blocks design with three replications  in Shahrekord University in 2016. Defficit irrigation as the main factor in four levels, including 50 (control), 80, 130 and 180 mm of evaporation from the class A evaporation pan, and the use of zeolite as a secondary factor in three levels, including non-use (control) and the use of 5 and 10 tons/hectares were considered. The results of the experiment showed that the application of zeolite at a probability level of 1% had a significant effect on the content of chlorophyll a, chlorophyll b, total chlorophyll and carotenoids of leaves, oil yield, nitrogen percentage, protein percentage and seed protein yield, allthogh, the oil percentage was not affected by this treatment. Also, different levels of irrigation were significant on all the mentioned traits at the level of 1%. The interaction of the simple effect of the treatments on protein percentage, nitrogen percentage, chlorophyll a and total chlorophyll was significant at the 1% probability level and on oil yield and chlorophyll b at the 5% probability level, and showed non-significance on the oil percentage, protein yield and carotenoid . The highest amount of the above traits was obtained from the control treatment (normal irrigation) and the application of 10 tons zeolite /hectare, and the lowest amount of the traits was obtained from the treatment of 180 mm of evaporation from the evaporation pan and no application of zeolite. The results showed that the application of zeolite has significantly improved the performance of the lineeed crop in non-stress conditions to moderate drought stress conditions.
Introduction
Oilseeds are big sources of energy and protein. Linseed (Linum usitatissimum) is an oilseed crop with a history of several thousand years of cultivation, which seeds contain 30 to 50% edible oil. Linseed is a one-year herbaceous plant belonging to the Linaceae family, which is believed to have originated in the western Mediterranean (Omidbeighi, 2014). The protein content of linseed seeds is between 29-44%. It has been reported (Iran-Nejad, 2014). Water defficit is one of the significant and important stresses affecting the growth, development and functions crops. Water stress in plants may lead to physiological disorders such as reduction of photosynthetic pigments, reduction of assimilates. and reduce growth (Petropoulos et al., 2008). water stress reduces the absorption of nutrients through the roots due to the reduction of soil water and the reduction of the distribution of nutrients in the soil tissue; it also reduces the transfer of nutrients from the roots to When plants are under stress, their chlorophyll content decreases and as a result, photosynthetic activity also decreases in plants under stress.
Materials and Methods
The field experiment has been conducted as a split plot based on a randomized complete block design with three replications at the research farm of Shahrekord University on linseed crop in 2016. The main factor water stress included four levels of 50 (control), 80, 130, the lowest irrigation level and 180 mm of evaporation from the evaporation pan, and the secondary factor of zeolite consumption in three levels, including control (without zeolite), 5 and 10 tons of zeolite per hectare. The traits of chlorophyll concentration (a, b and total), yield and yield components, thousand seed weight, oil percentage, seed oil yield, seed nitrogen percentage, protein percentage and seed protein yield were measured.
Results and Discussion
The experiment results showed that the application of zeolite on chlorophyll a, chlorophyll b, total chlorophyll and carotenoid, oil yield, nitrogen percentage, protein percentage and seed protein yield was significant at the probability level of 1% and it was not significant on oil percentage. Also, different irrigation levels were significant on all the mentioned traits at the level of 1%. The interaction effect of treatments on protein percentage, nitrogen percentage, chlorophyll a and total chlorophyll was significant at one percent probability level, and on oil yield and chlorophyll b at five percent probability level. It was not significant on oil percentage, protein yield, and carotenoid. The results showed that deficit irrigation reduced all investigated traits. So that the maximum amount of the above traits were obtained from the control treatment (normal irrigation) and the application of 10 tons of zeolite per hectare, and the lowest amount of traits was obtained from of 180 mm evaporation from the evaporation pan and the absence of zeolite application. The results showed that the use of zeolite, has significantly increased the yield of linseed crop under non-stress conditions to moderate drought stress conditions, but under severe stress conditions, the limiting effects of drought stress have significantly reduced the studied traits.
Conclusion
The results showed that the use of zeolite, due to its property of absorbing water, maintaining and increasing the availability of moisture, reduces the intensity of drought stress and moderates the destructive effects of drought stress on the content of chlorophyll, carotenoid, and protein in plants. In this research, it was found that the use of 10 tons of zeolite per hectare had a favorable effect on reducing the damage caused by drought stress in linseed crops, and considering the abundance of zeolite in different parts of the country and its reasonable economic price, as well as, the problem of drought stress in Iran, the use of Zeolite can improve plant access to soil water and increase yield and quality of oil and protein of linseed under water deficit conditions.