Apoptosis in detached corn root cap cells under fluorescent microscope was studied.A pair of homokaryon(CB37 and B37)inbred lines in maize was tested and the detached corn root cap cells might be using acridine orange staining.Apoptosis was found under fluorescence microscope treated by filtrated culture fluid of HMC toxin.The sensitivity of HMC toxin to C cytoplasm was greater than N cytoplasm,so that the quantity of the apoptosis was great more in the detached corn root cap cells with C cytoplasm than with N cytoplasm.Besides,apoptosis was not found in the CK.These indicated that special disease response occurred in the course of apoptosis in detached corn root cap cells of C cytoplasm maize led by HMC.

Resistance to maize southern leaf spot disease was induced by the low concentration of filtrate of Bipolars maydis race C toxin cultivation in an experiment.A pair of homokaryon C103 and B37 were used as the test material.The changes of peroxidase activity were related to the disease resistance of maize.The low concentration of Bipolaris maydis race C toxin cultivation as an elicitor is extensive and can be repeatable.The effect of 1∶ 60 in different disposal of CB37 and CC103 is better.

【Objective】The influence of filtrated culture fluid of HMC toxin on inducing disease-resistance and its related enzymes in specific host maize(Zea mays L.) leaves was studied.【Method】The various pathogenicities were detected by the detached leaf method on the specific host maize leaves of two pairs of homokaryon(B37 and C103) inbred lines to search effective dilution factor for inducing,and changes of disease resistance-related enzymes were measured after inoculation.【Result】The disease resistance was enhanced in different genotypes and cytoplasms induced by low concentration filtrated culture fluid of HMC toxin,the effect on C cytoplasm was higher than that on the N cytoplasm.Activities of disease resistance-related enzymes showed dynamic changes in different periods,and influences of disease-resistance were led by the different concentrations.【Conclusion】POD and PAL activity were increased and MDA content was decreased after pretreatment with filtrated culture fluid(1﹕50 or 1﹕ 60) of HMC toxin in order to start up maize defense system for itself.It played as a passivation to restrain the HMC infection.After inoculating by high concentration filtrated culture fluid of HMC toxin,the disease resistance-related enzymes were activated further.So,the sensitivity of C cytoplasm to HMC was reduced and disease resistance was represented.

Disease to maize southern leaf spot disease was induced by culture filtrate of Bipolaris maydis race C toxin cultivation.A pair of homokaryon B37 inbred lines in maize was used as the test material.The toxin activity was measured by the detached leaf method to find its optimal concentration as a plant defense activator that induces maize disease resistance,and several enzymes involved in disease resistance were presented.The lesion area on the leaves was significant difference by ANOVA.They were(0.30±0.14) and(0.36±0.17) mm2 respectively after pretreated with 1∶50 and 1∶60 of culture filtrate of Bipolaris maydis race C toxin cultivation were(0.30±0.14) and(0.36±0.17) mm2 respectively.It was decreased 7.5-9 times compared with the CK(2.70±0.24) mm2.At the same time,the changes of peroxidase(POD),phenylalanine ammonialyase(PAL),malondialdenvde(MDA) activities were determined.During 0-72 h inspection,the effect of 1∶60 concentration was better than that of 1∶50,PAL activity increased by 23.4%,POD activity increased by 65.9%,but the malondialdenvde(MDA) content decreased by 28.2% compared with the CK.It was shown that culture filtrate of Bipolaris maydis race C toxin cultivation itself can function as an elicitor to induce host disease resistance in maize.

Apoptosis in detached corn root cap cells under fluorescent microscope was studied. Homokaryon maize B37 inbred lines was tested and the detached corn root cap cells with cell wall might be stained using Hoechst33342. Apoptosis was found under fluorescence microscope treated by culture filtrate of HMC toxin. The sensitivity of HMC toxin to C cytoplasm was greater than N cytoplasm and there was more resistance response in detached corn root cap cells of N cytoplasm than C cytoplasm. Besides, apoptosis did not coincide at different processing times. These indicated that special disease response occurred in the course of apoptosis in detached corn root cap cells of C cytoplasm maize led by HMC which may be collective result of nucleus and cytoplasm.

In the experiment induced disease-resistance of maize by culture filtrate of HMC toxin was investigated.A pair of homokaryon maize C103 inbred lines were used as the test material.The pathogenicity was measured by the detached leaf method in order to find moderately diluted concentration for inducing disease-resistance.The results showed that lesion area decreased by 7.9~12.2 times.It was significantly different by ANOVA.Among the treatments,the effect of 1∶60 is better than 1∶50;POD and PAL activities increased by 57.8% and 52.9% respectively.However,MDA content decreased from by 38.2% compared with CK during 0~72 h inspection.In short,moderately diluted(1∶60) culture filtrate of HMC toxin could function as an elicitor to induce host disease-resistance in maize.

In the experiment,the leaves of maize were dealed with the low concentration filtrate of Bipolaris maydis race C toxin cultivation whose Malondialdenvde content is low.Two pair of homokary maize corn C103 and B37 were used as the test material.The low concentration filtrate of Bipolaris maydis race C toxin cultivation as an elicitor is extensive and can be repeatable.