Influences of Water Deficit Stress and Symbiosis with Growth-Promoting Bacteria on Seed Biochemistry of Camelina sativa

Abstract

Camelina sativa, being a flowering plant in the family Brassicaceae, is traditionally cultivated as an oilseed crop due to its exceptionally high level (up to 45%) of omega-3 fatty acids, which is uncommon in vegetable sources. In the recent years camelina has been growing more than before because of its potentiality in the production of biodiesel and bioproduct. An aforementioned experiment was designed in three irrigation levels (100%, 75% and 50% of field capacity) and Micrococcus yunnanensis was used as plant growth-promoting bacteria during the reproductive phase. The bacteria were incubated in a nutrient broth medium at the temperature of 28°C for 24h on shaker ceaselessly. When sowing, seeds were treated with 1.0 ml bacteria suspension in the inoculated groups. Water stress was applied to each pot in the levels of 75 and 50 % FC from the budding stage to full maturity in generative phase. Camelina silique yield was harvested at the maturity stage for analysis of seed quality and biochemical responses. Total soluble carbohydrate was extracted thrice from 100 mg of mature seed using extraction soluble including glacial acetic acid, methanol, and water. Oil and protein content were measured using Near-Infrared Reflectance spectrometer. Seed fatty acid contents were determined using gas chromatography. The results showed a significant relation between the highest proportion of fatty acid and the polyunsaturated fatty acid (55.12 to 65.66%) in particular linolenic acid. The increase of polyunsaturated fatty acid and saturated fatty acid was coincided with the decrease of monounsaturated fatty acid under water deficit stress. The application of plant growth-promoting bacteria is proven to increase protein with 50% of field capacity. In general, water deficit stress and plant growth-promoting bacteria have significant effects on the remobilization of nutrients from the soil to developing seed and following metabolism synthesis.