烤煙品種K326和云煙87對(duì)鎘脅迫的生理響應(yīng)及抗性差異
Physiological Response and Resistance of K326 and Yunyan87 to Cadmium
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摘要: 水培條件下,，研究鎘（Cd）脅迫后2個(gè)常用烤煙品種（K326和云煙87）對(duì)Cd的吸收及Cd在細(xì)胞中的分布,，比較Cd處理前后煙株的生物質(zhì)積累、葉綠素含量,、根系活力,、葉表及根尖微結(jié)構(gòu)的變化。結(jié)果表明，外源Cd處理使K326的生物量比對(duì)照降低37.7%,，云煙87生物量降低76.2%,；K326的總?cè)~綠素含量比對(duì)照降低64%，云煙87的降低53%,；K326根的活躍吸收面積比對(duì)照降低33.3%,，云煙87的降低13.9%。不加Cd時(shí),，2種煙草氣孔大小均一,，密度相近，Cd處理后,，兩者的氣孔均減小,，密度增大。在Cd的影響下,，K326品種的細(xì)胞直徑下降了35％,，云煙87的下降不顯著。Cd處理使完整飽滿的根尖變得皺縮平禿,。Cd處理使K326葉表腺毛腺頭變小,、腺毛變細(xì)，尤其腺基部變細(xì)更明顯,；Cd處理使云煙87葉表腺毛發(fā)育相對(duì)延遲,。Cd主要存在于K326和云煙87的根部，分別占總量的82%和89.4%,，在葉細(xì)胞的5個(gè)組分中,，以可溶性組分中最高，且K326中Cd的含量高于云煙87,。從生物質(zhì)積累量來(lái)看,，Cd處理對(duì)K326的影響小于對(duì)云煙87的影響，兩個(gè)煙草品種耐受Cd的能力差異較大,。Abstract: The uptake of cadmium by flue-cured tobacoo K326 and Yunyan87 and its distribution in plant cells were studied by hydroponic culture, with the comparison of biomass accumulation, chlorophyll content, root activity and microstructure changes in various treatments. The results showed that K326 decreased less than Yunyan87 in biomass, while in root activity and chlorophyll content, K326 declined more rapidly than Yunyan87. Without Cd, the size of stomas in K326 and Yunyan87 was homogeneous and the density of stomas appeared similar, whereas under Cd stress, reduced size of stomas and increased density of stomas occurred in both of the two tobacco varieties. Under Cd stress, Root diameter of K326 reduced by 35%, while no evident change was observed in Yunyan87. Cd stress migh result in abnormal root tip, and weak trichome of K326, and retarded development of trichome for Yunyan87. Cd was mainly detected in roots of the two varieties, with greatest distribution in soluble fraction of tobacco leaves. K326 exhibited more total level of Cd than in Yunyan87. Regarding biomass accumulation, Cd stress had less effect on K326 than Yunyan87. In summary, great differences of Cd tolerance exist between the two flue-cured tobacco varieties.
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