Phase Analysis of the Cellulose Triacetate-Nitromethane System

A comprehensive study was made on the cellulose triacetate-nitromethane system to explore its phase separation within ranges 2–25 wt.% and −5÷+80°C by means of polarization light and electron microscopy, the turbidity spectrum method, differential thermal and X-ray analyses, and rheological techniques. The physical state of the polymer was identified within the phase coexistence boundaries on the phase diagram which included three types of phase separation (amorphous (with a UCST at Tcr=57∘C and ccr=7.3 wt.%), crystal, and liquid crystal). The boundaries of the regions determining the coexistence of the liquid crystal (LC) and the partly crystal phase were found to be inside the region of amorphous liquid-liquid phase separation. For cellulose ester-solvent systems, this state diagram is the first experimental evidence for the possibility of coexistence of several phases with amorphous, LC, and crystal polymer ordering

Improved potato microclonal reproduction with the plant growth-promoting rhizobacteria Azospirillum

International audienceAbstractMicroclonal propagation in vitro is being actively used in the production of healthy planting material of food and ornamental plants. However, it needs further improvement to increase the growth rates of microclones in vitro and enhance regenerant survivability ex vitro. A promising approach to this end could be inoculating in vitro-micropropagated plants with plant growth-promoting rhizobacteria, specifically Azospirillum. However, the influence of Azospirillum inoculation on microclone behavior throughout the production process, including plant adaptation ex vitro and food crop productivity, has been underinvestigated. In this study, in vitro-growing potato (Solanum tuberosum L.) microclones were inoculated with Azospirillum brasilense strain Sp245. The microclones were then grown on in soil in the greenhouse and field, with the experiment lasting for 120 days. Root-associated bacteria were identified immunochemically, and the mitotic index of root meristematic cells was determined by a cytological method. The plant morphological parameters determined were shoot length, number of nodes per shoot, number of roots per plant, maximal root length, leaf area, percentage of surviving plants in the soil, and tuber yield and weight. Our results show that bacterial inoculation of potato microclones in vitro enhances plant adaptive capacity ex vitro and increases minituber yield. The percent survival index of field-grown inoculated plants was 1.5-fold greater than that of uninoculated plants. The overall tuber weight per plant was more than 30 % greater in the inoculated plants than it was in the control ones. For all cultivars on average, tuber yield per square meter increased by more than 45 % as a result of inoculation in vitro. This study is the first to report that Azospirillum inoculation of potato microclones not only improves the quality of planting material produced in vitro but also significantly increases minituber yield through enhancing plant adaptive capacity in the field