Physiological Research On The Dormancy Of Potato (Solanum Tuberosum) Tuber In Vitro

The history and the advancement of research on the tuber dormancy inpotato were introduced and reviewed in this thesis. And the dormancyfactors of the potato microtuber and the main regulation center of thedormancy release were studied. Protein factors and enzymes affectingpotato microtuber dormancy were identified after analysis of the dormancy regulation at the levels of translation and transcription.The results are as follows:1)It was suggested that, during the potato microtuber dormancy, thedormancy of apical buds on potato microtuber be inhibited bymicrotuber itself and the dormancy of lateral buds be affected byboth the apical dominance and microtuber itself. The main regulationcenter of the dormancy release was found in the apical meristem bystabbing different buds on tuber with GA3 and water.2)Potato tuber dormancy release was inhibited by Cycloheximideneither with the presence nor absence of gibberellic acid, but notby actinomycin D .This indicated that potato tuber dormancy releasemainly relys on protein synthesis, but not on nucleic acidone. It wasconcluded that there might be kinds of longevity mRNA in dormantmicrotubers and these mRNA could be templates for proteinsynthesis during dormancy releasing. Electrophoresis analysis oftotal protein revealed that two different molecular weightpolypeptide bands were found from dormancy breaking tubers. Thesynthesis of these two polypeptides were blocked by Cycloheximide.9This indicated that dormancy release of potato tuber might beassociated with the regulation of protein synthesis.3)By analysis of the enzymes related to dormancy, it was foundthat activities of amylase and activities of amylophosphorylase indormant microtubers were much lower than these in dormantreleased tubers. It can be concluded that energy was supplied byactivating the amylase and amylophosphorylase during dormancyrelease. Peroxide activity was much higher in dormant microtubersthan that in dormant released tubers. High active Peroxidase canreduce the concentration of IAA. Dormancy and dormancy releasingcould be regulated by peroxidase since high active peroxidasereduced concentration of IAA which affected tuber dormantreleasing. The results also showed polyphenol oxidase activity washigher in dormant microtubers than that in dormant released tubersPolyphenol oxidase activity decreased lightly during dormancybreaking of potato microtubers. It inferred that polyphenol oxidase regulated the respiration metabolism during potato tuber dormancyas it was the enzyme related to respiration.