干旱胁迫对烟草不同部位细胞程序化死亡的影响

为了解干旱胁迫对烟草不同部位细胞程序化死亡的影响,以中烟100（不耐旱）和农大202（耐旱）为材料,采用2.5% PEG-6000模拟干旱,分析了不同耐旱性材料表型差异,用DNA Ladder法、TUNEL法测定烟草不同部位细胞程序化死亡发生的时间及程度差异。结果表明：（1）干旱胁迫下,农大202和中烟100的生物量、根长、根直径均较对照下降,其中中烟100下降幅度更大且与对照达到极显著差异;（2）中烟100在干旱胁迫第3天,各部位均已发生PCD,但是不同部位对干旱胁迫的响应不同,叶片、侧根的PCD发生程度相近,根尖细胞发生程度明显高于叶片及侧根;（3）根据定位观察可知侧根皮层细胞以及远离叶脉的细胞较早发生PCD;（4）烟草的耐旱性越强,PCD发生较迟,发生程度也越弱。综上所述,干旱胁迫下烟草不同部位细胞发生PCD的时间和特征是有差异的,耐旱性不同的品种发生PCD的时间也是有差异的。

Effects of Drought Stress on Programmed Cell Death in Different Parts of Tobacco Plant

To understand the effects of drought stress on programmed cell death in different parts of tobacco plants, using Zhongyan 100 (not drought-tolerant) and Nongda 202 (drought-tolerant) as materials, 2.5% PEG-6000 was used to simulate drought stress in analyzing phenotypic difference between plants with different drought tolerance. DNA Ladder method and TUNEL method were used to determine the time and degree of programmed cell death in different parts of tobacco plants. The results showed that: (1) Under drought stress, the biomass, root length and root diameter of Nongda202 and Zhongyan100 decreased compared with the control. The decrease range of Zhongyan100 was larger and the difference with the control was extremely significant. (2) On the third day of drought treatment, PCD had occurred in all parts of Zhongyan 100 plants, but the response of different parts to drought stress was different. The degree of PCD in leaves and lateral roots was similar, and the degree of PCD in root tip cells was significantly higher than that in leaves and lateral roots. (3) According to the localization observation, cells of the lateral root cortex and cells far away from the veins developed PCD earlier. (4) Tobacco plants with higher drought tolerance showed later occurrence of PCD and weaker degree of occurrence. In summary, the time and characteristics of PCD in cells of different parts of tobacco plants under drought stress are different, and the time of PCD in plants with different drought tolerance is also different.