Determination Of Pollen Viability And Exploration Of Pollen Germination Conditions Of Wild Sweet Potato

The pollens of sweet potato were employed as experimental materials and theeffect of different storage conditions on the viability of pollen was investigated usingthe TTC dyeing. The results showed that with the extension of storage time andpreservation temperature，the pollen viability came down. It was more contribute tomaintaining pollen viability at low temperature with drying condition．Fresh pollens that dried for2h at4℃and stored at-20℃with desiccant wascultivated using the solid medium culture and pollens were not germinated. Freshpollens were used to liquid culture. The results showed that pollen germination ratewas low. The pollen tubes were short and bent deformation. In addition, inclusionswere overflowed.The effects of interaction of two factors on the pollen germination and growthwere tested. The results showed that0.05%boric acid and0.01%CaCl2were theoptimal conditions for sweet potato pollen germination，in which the rate of pollengermination was34.33%; The germination rate was the highest reached to an averageof35.88%for the culture medium with0.05%boric acid and pH5.5; Germination ratewas the highest reached to an average of37.58%for the culture medium with0.01%CaCl2and pH5.5.The effect of several factors on pollen germination and growth was tested, theresults showed that:1) Orthogonal design L16（4×32）range analysis method wasapplied. The results showed that pH value had the most important effect on pollengermination and growth followed by boric acid and CaCl2in order by the size of the R.The optimal culture medium for in vitro pollen germination was liquid culture mediasupplemented with sucrose10%、PEG-400015%、 boric acid0.05%、CaCl20.05%, with pH5.5, in which the rate of pollen germination was only34.19%.2)Analysis of variance results showed that boric acid, CaCl2and pH value have no greateffects on the germination of sweet potato pollen on above basis within the measurement ranges. The reason may be that measurement range was too small, orpollen viability was not strong, and the importance order of affecting pollengermination and growth was boric acid, CaCl2and the effect of pH value wasminimum. Results showed that the suitable liquid culture medium for pollengermination and growth was the one composed of20mmol/L MES、10%sucrose、15%PEG-4000、0.05%boric acid、0.01%CaCl2and pH5.5, in which pollengermination rate was the highest,45.13%.