Studies On Resistance Of Revulsant Inducing Chinese Cabbage To Resist Cruciferae Clubroot

Cruciferae clubroot is a kind of diseases in the cruciferous vegetables in China. It mainly harms cruciferous vegetables such as Chinese cabbage and mustard. Its pathogen is Plasmodiophora brassicae Wor., who can survive about10years in the soil. When crops infected by P. brassicae, tumor formed in the root. And the ground part grows slow and gets to wilting. Cruciferae clubroot trend to accelerating, and at present the main control method is chemical control. It acquires quick effect, but harmful to human and livestock, environmental, or difficult to degradation. Or it causes drug resistance. While plant induced resistance has more resistance extent, durability and stability, and does not affected by physiological kind. Revulsant we used is biological or non-toxic, slight-toxic chemicals, which is harmless to human and animal, and can overcome some defects of chemical control. Which is accord with the requirement of modern agricultural. Through greenhouse cultivation, this study includes:select one or two kinds of optimal revulsant; determine resistance related enzyme activity, discuss whether the revulsant affects the activity and mechanism; In turn, carry out field efficacy trials, to explore the role and application prospect of inducers to enhance cruciferae crops’resistance to clubroot disease in actual production.The main results are as follows.1. Determination of the method of induction treatmentBy two different processing ways-fill the root and foliar spray, it had obvious different effect to induce cabbage resist clubroot. Compared with foliar spray processing, fill the root with SZG7, ZHS-1, ZHS-2treatment have higher control effect,and the value added relatively by87.5%,94.44%and80%.2. Screen the revulsantUnder the same conditions, selected11kinds of revulsant (100mg/L). SZG7, ZHS-2, ZHS-1,BTH and C-22got relative higher control effect, respectively were56.25%,45.00%,43.75%,31.25%,31.25%. With the optimal concentration100mg/L, SZG7processing the best, and higher than BTH,ZHS-1, C-22and ZHS-2processing respectively by44.44%,18.18%,30%and62.5%.Resting spore germination inhibition test results shows that by ZHS-4and ZHS-2 processing, inhibit germination rate was17.90%and13.02%. By BTH and TDL treatmen, the rate were the lowest, only1.93%and2.90%. So it can be considered as no direct role in sterilization and bacteriostasis. While we can consider the revulsant provided had inducing role.3. Determination of induction length of time of resistance expressionTreatment with SZG7, the previous five days achieved optimum induced effect, and the effect was relatively lower in the following days, while it could last15days at lest.4. The determination of enzyme activitySZH7treatment, compared with CK, after inoculation of pathogen, SZH7-pathogen,SZH7-no pathogen and CK-pathogen cabbages:POD activity, SOD activity, CAT activity, MAD concentration and content, PAL activity, PPO activity, soluble sugar concentration and content were increased obviously. And the enzyme activities rising faster than non-induced plants (CK-no pathogen and CK-pathogen).5. Revulsant impacts on Chinese cabbage resisting infection of P. brassicaeThe number of root hair infection increased by days, and were diverse in different parts of the root. The number was small in root0-1cm, and the maximum in2-3cm. It was the main area P. brassicae infected the root1-4cm. No root hair invaded outside5cm.Saw1-3cm root hair, there was no infection in the initial3days of induction treatment. The number increased by days in the following days.When the spores concentration was less than or equal to103/mL, there is almost no infection. When more than103/mL, with the increase of spore concentration, the the infection number increased consistently.With the increase of revulsant concentrations (0-100mg/L), root hair infection number reduced gradually, and the number minimum in100mg/L-50%less than comparison; When more than100mg/L, the infection increased gradually,and the number in200mg/L maximum, but still15%lower than the contrast.6. Field efficacy trialsDisposed with different revulsant, the relative control effect were not identical. At different sites, due to different objective conditions such as the topography, temperature and humidity, the control effects are also different by the same revulsant. In general, kejia effect best, and XF-1second. Last the actinomycetes22-29fermented liquid and revulsant treatment. But it can be seen from table7, besides kejia processing had the highest relative control effect of78.84%, SZG7can achieve relative control effect of63.72%also.