Journal of Plant Process and Function

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In order to investigate the effect of different levels of water stress on Satureja hortensis, a completely randomized design (CRD) with four replications was carried out in the greenhouse of Yazd University in 2014. The water stress treatments including 100, 75, 50 and 25 Percent of field capacity (FC) were applied. The results showed that water deficit stress significantly (p<0.01) decreased plant height, canopy cover volume, canopy cover surface, shoot dry weight and root dry weigh, root thickness as well as soluble sugars content. Also, proline, chlorophyll content and root length significantly increased under drought stress. The maximum amount of proline, a, b and total chlorophyll and root length was observed in 25% of field capacity. Maximum plant height, crown volume and leaf area was obtained at 75% of field capacity. The shoots and roots dry weight of and crown area was observed in plant treated at 100% of field capacity. The overall results of this study showed that S.hortensis with can be adapted to drought stress by using some avoidance mechanisms such as reduced plant height, plant volume, surface and crown diameter, shoot and root dry weight, root thickness and increasing of chlorophyll contents and proline.

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Knowledge concerning some physiological and biochemical basis of flowering process is essential for achieving higher yield and quality of saffron. This study aimed to elucidate the relation between flower mass ratio and a rough content of carbohydrate, starch and protein of plants do produce flower and non-blooming saffron at flowering stage, affecting on flower development and to determine mass-flowering pattern based on comparison of carbohydrate, and protein content of saffron corms as well as the antioxidant enzyme activities at stages of complete dormancy, flowering and vegetative growth. 120 healthy and uniform weight saffron corms were selected and were grown in a completely randomized design (CRD) with three replicates and placed in a growth chamber. Corms were sampled separately during the dormancy stages (mid-August), flowering (late October) and vegetative growth (January). The results showed that sugar content at flowering stage was increased 65.6% compared to complete dormancy stage and starch content was decreased 32% in vegetative growth stage compared to flowering stage. Catalase enzyme activity was at its maximum level (3 μmol H₂O₂ min ^-1 mg^-1 protein) and peroxidase at vegetative stage (2.6 μmol POX min ^-1 mg^-1 protein). Due to the lower starch content in plants do produce flower than non-blooming saffron plants, it can be concluded that the plant may convert the starch in the corm of saffron into sugar, depending on its need at the flowering stage, and exchange these two substances as needed. Among the antioxidant enzymes investigated, it was found that the peroxidase enzyme usually acts as a multifunctional enzyme and can enhance or inhibit flower induction.