Effects Of Enhanced Ultraviolet-B Radiation On Chromosomes And Microtubule Arrays In Wheat Root Tip Cells

The ozone layer of the atmosphere can make the earth’secosystem balance. Ozone is capable of absorbing ultravioletradiation of the sun light. And the ultraviolet radiation has greatdestructive power on lives which exist on earth. Therefore, theprotection of the ozone layer is great significance for normal lifeactivities of human beings, animals and plants. In recent years,human activities have released a large amount of pollution gasesdestroying ozone, which leads to making a dramatic increase of uvradiation on the ground. The current condition has caused aprofound damage to metabolism of plant growth, physiology andbiochemistry and genetic development. Wheat is one of theimportant food crops in the world whose total production camesecond. It should be not ignored that the yield reduction of crops iscaused by enhanced UV-B radiation. Thus, it is extremely importantto reveal mechanisms in which enhanced UV-B radiation respondsto reflecting and being damaged.Microtubules play a very important role in the process of plantgrowth and morphogenesis. It is not only a skeleton supportingcells which serves as a channel of material transport, but also the key factor of mitosis. This study used oryzalin (concentration:500μmol L–1) and enhanced UV B radiation (dose:10.08kJm-2day-1)to treat wheat root tip cells and control group, enhanced UV-Bradiation treatment, oryzalin treatment, a combination of oryzalinand enhanced UV B radiation were set up, investigating the effect ofthe microtubule arrays on wheat root tip cell chromosomeaberrations caused by enhanced UV-B radiation. Get the followingconclusions:1. The comparing of different effect of the GFP technology andimmunofluorescence technology on cell marking is made throughGFP and antibodies labeled arabidopsis roots and mesophyll cell.And Western blot was used to test the combined situation ofantibody and microtubule protein in wheat root tip cell, provingantibody label subunit and microtubules in wheat.2. Observation of the four treatments by using laser scanningconfocal microscope showed: Oryzalin induced chromosomedoubling showed two equal nucleus, and combined enhanced UV-Bradiation has showed two unequal nucleus. Count the frequenciesof equal and unequal nuleus in the four treatments showed thefrequency of unequal nuleus in the treatment of OB wasconspicuously increased compared with other treatments.3. In the mitotic phase of wheat root tip cells, we observedabnormal microtubule arrays including asymmetry PPB, asymmetryspindle and defective phragmoplast in different phase by usingindirect immunofluorescence and chromosome aberrationsappeared. But when microtubule arrays depolymerized, thechromosome aberrations appeared,too. 4. Co-localization of microtubule arrays and chromosomes in“3-bundle division” caused by enhanced UV-B radiation showed:Whether the microtubules arranged cell plate appeared in the cellplate position, the “3-bundle division” formed.Above all,we speculated that: although microtubule distortionscan also caused chromosome aberrations, in pathway ofenhanced UV-B radiation caused chromosome aberrations, theaberrations was not caused by microtubule distortions, and it ispossible that by influencing the other factors which concerned withcell polarity to cause chromosome aberrations.