Research On The Change Rule About Physiological And Biochemical Substance Of The Onions While Vernalization And Bolting

Onion (Allium cepa L.),lily (Liliaceae), Allium(Allium), biennial plants,the area of worldvegetable production,which is second to potatoes and tomatoes, the area and production ofChinese onion is the first in the world at present, but the onion above seedling diameter thick0.5cm,and2-10℃sustained low temperature could easily complete vernalization, andimmature bolting occurs, causing serious economic losses, so when the temperature durationis longer, will be to risk, coupled with the global warming in recent years, warm winterweather occurred frequently, so in production to be able to warning, andtimely take measures to reduce losses for onion cultivation is of great significance.To control onion physiological characteristics and the mechanism of flower buddifferentiation and flowering,and for Snow and Golden Red No.1onion low-temperatureprocessing and bolting, find soluble sugar, soluble protein, active oxygen removal of thelevels of enzyme activity, nucleic acid, and endogenous hormone and flowering and boltinghas certain relevance, explore green onion bolting with its main physiological andbiochemical substances of inner link, in order to bolting Onions to make predictionforecasting, early warning, thus reducing the onion cultivation losses.1. Through the low temperature treatment and the control group the onion leaf solublesugar and soluble protein determination, studies have found that soluble sugar increased afterlow temperature treatment, but when the flower bud differentiation phase is complete boltingdown again, and in the control group bulb formed in the early soluble sugar has been reducedthen content rise in late stage, when the bulbs stop growing tend to stable. After lowtemperature treatment and in the process of bolting, soluble protein content appear increase,decrease of the change trend, the control group is a trend of up-down-up first.2. Onion leaf CAT in the whole process of flower bud differentiation to bloom appear thefirst decreases after rising trend overall, in full bloom the CAT activity in a temporary peakand then decline, while SOD activity changing trend is similar to the change trend of theCAT, and POD activity shows bimodal curve, raise-lower-raise-lower. In the process offlower bud differentiation to bolting,cell metabolic activity, gradually enriched in plants moresuper oxygen free radicals, leading to the increase of SOD activity, along with the plant invivo metabolism of active oxygen increase, accumulation of H2O2, the activity of CAT alsowill increase, and the POD are ubiquitous enzymes in plants and involved in a wide variety ofphysiological activities in body, as in the process of flowering metabolism increase andenzyme activity strengthening,after budding and full bloom have fallen slightly, Snow White and the Red one, the changing rule of the two varieties of three kinds of enzyme activity inthe basic consistent, but there are differences in change.3. Onion total nucleic acid began to rise after low temperature treatment, peaked andbegan to decline then rise,comparison is also appear a similar rise and fall trend, but the wholeprocess in the control group total nucleic acid content is always lower. DNA, RNA, and totalnucleic acid changing tendency is consistent, but DNA level change is small, the change ofnucleic acid is mainly reflected on the RNA content changes, this period is given priority towith RNA a lot of replication, RNA/DNA levels gradually increased, while the control groupRNA/DNA values on the rise-down-up trend.4. By early low-temperature treatment processing, onion leaf of GA3, IAA content isalready at a high level, high level of GA3, IAA, unfavorable to flower bud differentiation, GA3and IAA levels then gradually reduce for the direction of favorable to flower buddifferentiation, then began to recover, and the level of ABA on the contrary, the early lowerand gradually accumulate. GA3content is higher in all process, the budding period of GA3,IAA level is relatively higher, may has relation with dynamic balance of hormone. WhileABA levels were lower in the flower bud development, elevated levels in the late flowering,promote the seed mature. As to speak in the process of low temperature treatment andvernalization complete, three kind of endogenous hormone content with the intense change,eventually achieve dynamic balance state, promote flower bud differentiation complete. GA3,IAA and ABA several different kinds of plant hormones’ physiological effect with mutualpromotion and mutual antagonism effect, so the balance of the relationship between planthormones on plant growth and development is more important.