| The research on the transport of soil water and nutrients on sloping land is an interdisciplinary area between soil erosion and dryland farming. The research is also the common field between soil science and environmental science. The transport mechanisms of soil water and nutrients on slope land are very important both in theory and practice for understanding the principle of soil degradation, environmental protection and increasing the productivity of dryland farming. In this dissertation, the transport of phosphorus, particle composition, water, and their distributions along slope land were studied with methods of simulated and natural rainfall experiments. The following results were obtained:1 The results of experiments showed that rainfall intensities, surface slope gradient and soil tilled or compacted conditions significantly affected the soil water transport on slope. For 15?slope and compacted surface condition, the average infiltration ratio (za) was significantly correlative with rainfall intensities (IR) in parabolic relationship: ia =-1.3302/R2 +3.5926iR -1.418 . According to the equation the critical IR (1.35mm/min)and the max ia (l.Olmm/min) can be evaluated. The initial runoff-yielding time (tp) decreased with the increase of IR in power function. The depth of the lost runoff from slope and the runoff ratio increased with the increase of IR in linear function. The tp reduced with the increase of slope gradient, but little was changed in ia. Comparing the compacted surface with the tilled condition, tp became obviously short; ia reduced by 40%~60%; the total depth of runoff and runoff ratio increased by 1~5 times. Statistical analysis showed that, ia all decreased in power function for different rainfall intensities, slope gradient and tilled or compacted surface soil conditions. Tillage significantly accelerated the reduction of ia and obviously decreased the stable infiltration ratio. The runoff-yielding intensity () over slope surface increased with the extension of runoff-yielding time (tK) in a logarithmic function: VR=aLn(tR)+b. Tillage caused the significant increase of VR. The impacts of rainfall intensities and slope gradient on the infiltration depth of soil water during the rainfall process were not significant, but the average soil moisture in the profile slightly increased down from the top to the bottom of the slope. The transformed ratio (TR) from rainfall to soil water decreased with rainfall intensities. The order of soil water content for different slope gradients, was: 5?25?15? Tillage significantly decreased the average soil moisture and TR. There all existed the characteristics of soil water fluctuation both in the surface layer (0-5cm and 5-10cm) andlycopene synthesis in TEBE was mainly through improving the expressions of up-stream genes including PSY and ZDS, and the enhancement of lycopene synthesis in Xin Touxinhong was mainly by suppressing the expression of down-stream gene, LYC-b. All the factors just influenced the levels of lycopene synthesis, did not change the content rate of lycopene to 0 -carotene in TEBE system. While higher concentrations of PO43" and sucrose, culture temperature of 20 癈 and longer culture duration (25 days) not only promoted the lycopene synthesis in the cells of Xin Touxinhong to a higher level, but also changed the content rate of lycopene to ^ -carotene from less than 1 to more than 1. Those factors were the most favorite effectors for lycopene synthesis in Xin Touxinhong suspension system.The above results clarified the effectiveness and feasibility of regulation lycopene metabolism in plant by using anti-sense RNA of lycopene b-cyclase and modulating the effectors improving lycopene synthesis in cell suspension system. The combination of the gene regulation and cell culture system for secondary metabolism will significantly improve the secondary metabolite production in the future.Keywords:Carrot(Daucus carota L.);Lycopene;Lycopene b-cyclase;Anti-sense RNA;Effectorsin the deep layer (0-2m). Slope types obviously affe... |
PDF Full Text Request