Study On The Coupling Effect Of Water And Fertilizer On Toona Sinensis At Seedling Stage

Toona sinensis is an important timber species traditionally cultivated in Chinese warm temperate zone and a common ornamental tree species.It is rich in nutrients,excellent in wood,and beautiful in tree shape.It has high medicinal edible value and economic value.For a long time,the national government has vigorously promoted and planted a large area of camphor plantations.However,the research on key cultivation techniques such as water and fertilizer ratio are relatively scarce.How to respond to water and fertilizer effects is a problem worthy of discussion.In view of this,it is of great theoretical and practical significance to study the interaction mechanism of water and nitrogen in Toona sinensis.In this paper,the annual grafted seedlings of camphor were used as experimental objects,and two water gradients(W1=15%soil moisture content,W2=60%soil moisture content)and four nitrogen levels(N0=0g,N1=1g,N2=2g,N4=4g)interaction design,a total of eight treatments,using artificial control pot experiment,observe and analyze the growth morphology and physiological metabolic index of seedlings under different water and nitrogen interaction treatment,using mathematical statistical methods to analyze the water and nitrogen interaction on the growth and development of Toona sinensis seedlings The main results of the morphological and physiological characteristics are as follows:1.Drought severely inhibits the elongation of the main stem and the development of leaves.The application of appropriate nitrogen fertilizer can promote the growth of seedling height,prolong the leaf-expansion period,increase the leaf area,promote the growth and development of leaves,and delay the senescence of leaves.Nitrogen application under drought treatment had no significant effect on root surface area and root mean diameter.The suitable water and fertilizer conditions can effectively promote root growth and increase the absorption area of the root system.Excessive application of nitrogen can inhibit the root system.2.Water and nitrogen interaction had significant effects on leaf water content,specific leaf weight,stomatal conductance,transpiration rate,chlorophyll a content,carotenoid content,antioxidant enzymes and osmotic adjustment substances.Nitrogen application can reduce the degree of drought stress,increase chlorophyll content and enhance the photosynthetic capacity of Toona sinensis leaves.The average nitrogen fertilizer effect of protective enzyme activity and osmotic adjustment substance content under the same water condition showed high and low in both ends,indicating that nitrogen deficiency and excessive nitrogen application would increase it.Rational nitrogen application can weaken the membrane of citronella leaf to some extent.The degree of lipid peroxidation slows down the process of drought stress.3.The interaction between water and nitrogen has a significant effect on the biomass and nitrogen absorption and utilization efficiency of Toona sinensis.Reasonable water and fertilizer conditions can effectively promote the accumulation of dry matter in the biomass of camphor,and the promotion of aboveground biomass is more obvious.The interaction of water and nitrogen promotes the accumulation of nitrogen in the plants mainly in the leaves,and the reasonable soil water content can promote the nitrogen transfer to the roots.The nitrogen uptake efficiency of plants under water treatment was higher than that of drought treatment,indicating that water promoted nitrogen uptake by plants.Under the two water contents,nitrogen use efficiency decreased with increasing nitrogen levels,indicating that plants were nitrogen.The demand for the hormone is reduced,and the excessive nitrogen fertilizer causes the nitrogen use efficiency of the plant to decrease.4.In summary,the toon is maintained in a fertile and humid environment to maintain a faster growth rate and better growth quality.Insufficient water and nutrients will inhibit the growth of the camphor,but the camphor can adapt to the poor and poor environment through a series of growth patterns and physiological adjustments.Specifically,camphor increases a series of measures such as protecting enzyme activity,osmotic adjustment substance content,increasing nitrogen absorption efficiency,and changing biomass allocation ratio to maintain good growth.