Assessment of changes in yield components, yield and some physiological traits of Thymus vulgaris and Thymus daenensis under drought stress and application of manure

One of the negative effects of drought stress, reducing availability and absorption of nutrients for the plant(omidi, 2012). Manure increase soil fertility and improves the growth and yield(Fallah et al., 2007). This study conducted to evaluate some morphological and physiological characteristics of two species of thyme plant under drought stress and manure.
Experiment was at the field of the Faculty of Agronomy of the University of Birjand, Birjand, Iran with located at latitude 53º: 32N, longitude 13:55ºE and altitude 1480 m above sea level in 2015.In order to evaluate the effects of different levels of drought stress and manure on Thymus vulgaris and Thymus danensis, an experiment was conducted as factorial based on a RCBD with 3 replications in 2015.Treatments were combination of three water stress levels 100% FC, 67% FC and 33% FC, manure at two levels: the no manure and consume 30 t.ha-1, and two species of Thymus vulgaris and Thymus daenensis.
Measurements of Leaf pigments (Chlorophyll a and b, Carotenoid and concentrations): 0.1g samples were taken from the collected leaves. Subsequently each sample was extracted by 80% acetone and put in the centrifuges with rotation speed of 6000 per minute for 10 minute. Absorbance using a spectrophotometer at wavelengths of 470, 647, 663 nm was measured. Pigments were determined according to Lichthenthaler (1987).
Measurements of Anthocyanin: 0.1g samples were taken from the collected leaves Subsequently each sample was extracted by methanol and put in the test tube in dark place for 24 hours then put in the centrifuges with rotation speed of 4000 per minute for 10 minute. Absorbance using a spectrophotometer at wavelengths of 550 nm was measured. Pigments were determined according to Wanger(1979).
Measurements of Yield and yield components: For this purpose, three plants were harvested from crop lines. After drying the samples in an oven at 72 ° C for 48 hours the dry weight of stem, leaf, flower and total dry weight of each sample was measured.
Statistical analyses were carried out by ANOVA, with a multiple range test (LSD) for subsequent pairwise comparisons. Data were analyzed using of SAS to compare the difference between the treatments.
Leaf pigments: The highest Ch a, b obtained from of Thymus danensis. Carotenoid content increased under drought stress. The highest and lowest Carotenoid content obtained from of 33% Fc(The highest level of drought) and 100% Fc(normal condition) respectively. Among species, Thymus vulgaris showed the highest and Thymus danensis showed lowest Carotenoid content respectively. Manure while reducing the effects of drought stress and Cha, b increased under 30ton.ha-1 manure but manure reduced the amount of carotenoids.
Anthocyanin: Anthocyanin content was increased under drought stress levels. The highest and lowest Anthocyanin contents were obtained from of 33% Fc(The highest level of drought) and 100% Fc(normal condition) respectively. Among species, Thymus vulgaris showed the highest and Thymus danensis showed lowest Carotenoid content respectively. Also the highest and lowest Anthocyanin content obtained from of no manure and 30ton.ha-1 manure respectively.
Leaf and shoot dry weight: Leaf and shoot dry weight decreased under drought stress. The highest and lowest Leaf and shoot dry weight obtained from of 100% Fc(normal condition) and 33% Fc(The highest level of drought) respectively. Thymus danensis showed the highest and Thymus vulgaris showed lowest Leaf and shoot dry weight respectively. Among manure treatment, 30ton.ha-1 manure showed the highest Leaf and shoot dry weight.
Leaf dry weight to shoot: The highest and lowest Leaf dry weight to shoot obtained from of 100% Fc(normal condition) and 33% Fc(The highest level of drought) respectively. Leaf dry weight to shoot increased drought 30ton.ha-1 manure and the highest Leaf dry weight to shoot obtained from of 30ton.ha-1 manure.
Flower dry weight: The highest and lowest Flower dry weight obtained from of 100%Fc and Thymus danensis and 33%Fc and Thymus vulgaris respectively. Manure reduced the effects of drought stress and the highest and lowest Flower dry weight obtained from of Thymus danensis and 30ton.ha-1 manure and Thymus vulgaris and no manure respectively.
Total Dry Matter: The highest and lowest total dry Matter obtained from of 100%Fc and Thymus danensis and 33%Fc and Thymus vulgaris respectively. Interaction of manure in species showed that the highest and lowest total dry matter obtained from of Thymus danensis and 30ton.ha-1 manure and Thymus vulgaris and no manure respectively.
The main goal of this study was the selection of species that contain higher yield. Where in this study the Thymus vulgaris demonstrate the highest pigment and the highest yield compared to the Thymus vulgaris Therefore, According to these results we can say Thymus daenensis can grow successfully in arid and semi-arid. Also application of manure on food and water resource management and drought stress conditions in order to achieve the desired yield is recommended.