Studies On Pollen Viability, Storage Method And Effect Of Radioactive Breeding On Seeds Germination Of Lagerstroemia Indica

Lagerstroemia indica, which belongs to Lythraceae, is a kind ofimportant ornamental plant in summer and it is widely applied on the garden. Thepresent research on the L. Indica is deepening and it mainly concentrate oncultivation and breeding,assortment and insect pest study while there has lessreport on the crape myrtle palynology and radioactive breeding. This paper isdivided into two parts. In the first part, we study the viability determination andstorage method of the mixed pollen of four varieties of L. Indica; we determine theviability of different kinds of L. Indica pollen under different drying methods,different levels of maturity and different assay methods; we compare the effects onpollen germination rate in vitro culture under different in vitro culture methods anddifferent ratios of medium; we study the effects on the storability of L. Indica pollenunder different storage conditions. The second part researches on the radioactivebreeding of L. Indica and the effects on the germination of hybrid powder underdifferent radiation dosages. The specific conclusions of the paper are as follows:In this article, the viability determination and storage method aim at mixingpollen of four varieties of L. indica have been studied systematically, determineddifferent drying methods, different levels of maturity, different assay methods and theviability of different kinds of pollen, compared the effects of different in vitroculture methods and culture medium on pollen germination rate in vitro and studiedthe effect of different storage conditions on L. indica pollen viability.The researchcontents and the conclusions as follows:1. The optimization of the component and the method for pollen culture in vitro. Invitro culture using three factors three levels orthogonal experiment. After cultured thepollen kiln dried and air dried with bottle cap and glass microscope slides separately,the best culture medium proportion is：200g· L^-1Sucrose+150mg· L^-1boric acid+ 20mg· L^-1CaCl₂.In different condition，Sucrose, CaCl₂and boric acid could affectthe L. indica pollen germination rate. The pollen germination rate of kiln dried pollenlower than air dried pollen, culture the pollen with bottle cap also has a higher pollengermination rate.2. The choice of pollen viability determination method. L. indica pollen couldn’t bedyed by TTC solution, so it not using for determining pollen’s viability. I-KI stainingmethod with highest staining rate, HAc staining method take second place, isolatedculture with the lowest germination rate. These two kinds of staining method fordetermining the pollen’s staining rate in different maturity with very fine distinctions.The germination rate with isolate culture is: full bloom period> young blooms period> bud period. The pollen’s viability that determined with these three kinds of methodswill tend to drop off over time. However, the thing that the viability with isolateculture hold time at most9days, and the two kinds of staining method could keep ahigh staining rate after a year, it’s inconsistent with the facts. So, the I-KI stainingmethod and acetic red dyeing couldn’t explain the pollen’s capability to germinate,but it could be used for analyzing the fresh pollen’s qualification when it in the wild.In vitro culture method is the best way to test L. indica pollen’s viability.3. The compare of pollen’s viability during different kinds of pollen. When pollen invitro culture, with I-KI staining method and acetic red dyeing, the test result of thesethree kinds of pollen（the long stamens pollen, the short stamens pollen and mixedpollen） have inconspicuous differences, that means long stamens pollen has a sameviability with short stamens pollen.4. The reaction that acetone, benzene and petroleum ether to pollen’s storage. Storethe pollen with acetone at the temperature4℃, the germination rate is10.2%on thenext day. Store the pollen with the other two kinds of organic solvent, the germinationrate all below10%on the next day, and below5%on the third day. In the aspect ofgermination rate and storage time, though organic solvent could be stored for3⁶days, the storage effect of it worse than other treatment for pollen at the sametemperature, therefore, the three kinds of organic solvent that were chosen in theexperiment are not suit for storing L. indica pollen.5. The compare during CK, shading treatment and drying treatment under the threetemperatures. The pollen with drying treatment under the room temperature, theviability could keep9days, and the pollen with CK and shading treatment under theroom temperature, the storage time are5days and6days. On the condition of-20℃, pollen with shading treatment, the storage time is7days, and with other twotreatments, the storage time are all8days; the pollen viability lower day by day underthe room temperature, declining slowly on the condition of4℃, decreasing rapidlyon the second day under temperature-20℃. So, as a whole, storing effect with dryingtreatment is better than the other two kinds of treatment, and with CK and shadingtreatment only has a fine distinction; to compare the three temperatures, the beststoring effect is under the temperature4℃, next is room temperature and the last is-20℃.Based on the needs of production, this paper study the viabilitydetermination,storage method and radioactive breeding of the L. indica pollen. Itprovides theory evidence and operation instruction to further breeding work whichhas significance both in the scientific research and production.We have the comparison of seeds germination under different radiationdoses.The seeds of L.‘ZaZhong Fen’ were irradiated by different doses of60CO-γ rayin2012and2013.Results showed that the seeds in2012had higher CK germinationrate,speed of germination and uniformity than that in2013since the temperature in2012was higher than that in2013.But with higher radiation doses,seeds in2013hadlower germination rate,speed of germination and uniformity.So we concluded that thegermination process could be accelerated by appropriate high temperature and whenradiation dose was in the range of100to250Gy,the inhibition effects weresignificantly increased with radiation doses increase.