69 results about "Nitrogen deficiency" patented technology

The invention discloses a method for improving biomass and oil accumulation of oleaginous microalgae Scenedesmusdimorphus by adopting a two-stage culture strategy of co-culture and nitrogen deficiency, and belongs to the technical field of microalgae bioenergy. The invention adds a certain concentration of organic carbon source glucose to the autotrophic culture medium, and carries out concurrent culture with CO2 as the autotrophic carbon source. At the same time, under nitrogen-enriched conditions, after high-density culture of microalgae to a stable stage, the algae liquid is transferred to a nitrogen-deficient medium to continue the culture. When the glucose concentration is 1.2-5.4g/L, the initial pH is 7, and the culture time is 14-16 days, the biomass of microalgae can reach up to 4.5g/L, which is 2.57 times the biomass under autotrophic conditions; nitrogen deficiency Under these conditions, the total lipid content of microalgae reaches the highest of 29.62%, which is 1.6 times that of the nitrogen-enriched stage. By adding organic carbon sources and providing nitrogen-deficient conditions for two-stage culture, the biomass of microalgae can be effectively increased and oil accumulation can be promoted, which is of great significance to the research of large-scale production of bioenergy by microalgae.

The invention relates to a method for recommending a nitrogen fertilizer for wheat according to a relative SPAD (Soil and Plant Analyzer Development) value of a plant leaf. The method comprises the following steps: 1) setting field trial treatment (cells) of different nitrogen application levels, so as to cover gradient levels of soil nitrogen supply from nitrogen deficiency to excessive nitrogen supply; 2) testing the yield of wheat of soil under different nitrogen supply levels, and calculating an optimal soil nitrogen supply amount with the maximum wheat yield according to the relationship of the wheat yield and the soil nitrogen supply amount; 3) testing leaf SPAD values under different soil nitrogen supply conditions, calculating the relative SPAD value, and establishing a relationship model of the relative SPAD value and the soil nitrogen supply; and 4) testing the SPAD value of wheat to be supplied with the nitrogen fertilizer, calculating a relative SPAD value, and confirming the nitrogen fertilizer recommending amount according to the optimal soil nitrogen supply amount and the relationship model of the relative SPAD value and the soil nitrogen supply amount. By adopting the method provided by the invention, dynamic demands of the crop on a nitrogen nutrient component can be precisely matched, so that the yield of the crop can be increased, and the nitrogen fertilizer utilization efficiency can be improved.

The present invention relates to a method for promoting accumulation of microalgae oil under high-light and nitrogen-deficiency stress by using melatonin, and belongs to the field of microalgae biotechnology. A BG-11 basic medium using 10 g/L of glucose as a carbon source conducts heterotrophic culture of monoraphidium sp.QLY-1 at a temperature condition of 24-26 DEG C, algae cells are collected until the monoraphidium sp.QLY-1 grows to a late logarithmic phase, and a nitrogen-deficiency BG-11 culture medium dilutes the resuspended algae cells to 0.7 g/L as an inducing algae solution; absoluteethanol is used to prepare 10 mmol/L of a melatonin mother solution, the melatonin mother solution is added to the inducing algae solution to dilute a concentration of the melatonin into 10-80 [mu]mol/L, and the solution is subjected to induced culture at a temperature of 24-26 DEG C and an illumination intensity of 100-120 [mu]mol m<-2> s<-1>; and oil in the algae cells is extracted with an organic solvent. The method is simple in operation, can shorten induction cycle of the algae cells, increases content of oil, ensures growth of the microalgae, and can solve problems of biomass reduction,low oil content, etc. in an induction process of microalgae industrialization.