Investigating the Effect of Mycorrhizal Arbuscular Fungus and Vermiculus Solubilizing on Morphological and Physiological Traits of Gazania under Drought Stress Conditions

Drought is one of the major environmental constraints that limits plant growth and productivity more than any other environmental factors. Recent Mycorrhizal arbescular application to affeviate drought stress in many plants has been reported. Vermiwash can be used in two forms of foliar application or drench. It contains several enzymes, plant growth hormones, vitamins and macro and micro nutrients which can enhance plants tolerance to biotic and abiotic stress, as well as crop yield efficiency.

In order to investigate Mycorrhizal arbuscular fungi and Vermiwash foliar application on Gazania (Gazania rigens L.) growth and flowering characteristics under drought stress a greenhouse experiment with factorial design was conducted based on complete randomized blocks by considering three factors including MA fungi in two levels (incubation with MA and non- incubated plants), Vermiwash foliar application in four levels (0, 50, 100 and 200 ppm) and imposing drought stress in three levels (irrigation based on 40, 70 and 100% field capacity) with three replications in the greenhouse and laboratory of the Campus of Agriculture and Natural Resources of Tehran University in 2018. Studied traits involved plant height, number and leaf area, flower diameter and number, aerial fresh and dry weight, chlorophyll and carotenoid amount, N, P and K quantity of leaves. Analysis of variance’s results indicated that the influence of main effect of droughtt stress, MA and Vermiwash on the measured traits were considerably functional.

The maximum value of leaf’s carbohydrate was achieved in drought stress with the high severity in 40% of FC witch was 32.46 mg/gr. MA caused elevation in macro elements amount of the leaves. Foliar application of Vermiwash increased flower number and dimention and macro elements amounts as well. Among the Vermiwash treatments, foliat application of 200 ppm treatment reduced the negative effects of drought stress on plants. Comparison of the mean of dual effect of vermicompost in drought stress showed that the highest plant height in 200 ppm Vermiwash was 100% irrigation and the lowest value was in 50 ppm Vermiwash in irrigation 40% of field capacity. The lowest amount of chlorophyll a was observed in 40% water capacity and no Mycorrhizal fungi application. The highest leaf carbohydrate content was observed in irrigation treatments with 40% and 200 ppm Vermiwash.

vegetative growth decreased with increasig drought stress intensity from optimal irrigation level to severe stress. The use of Mycorrhiza and Vermiwash was positive compared to the control (Non-use), consumption of 100 and 200 ppm Vermiwash has better performance than other levels. Gazania responds to intense stress with more intensity than mild stress. It is recommended to prevent severe stress during the plant growth period. In this regard, the use of symbiotic fungi as well as Vermiwash foliar application (100 and 200 ppm) can help maintain plant growth by increasing plant tolerance to increasing stress intensity.