增加烟草一级和二级侧根是抵御干旱的生理机制

发布时间：2018-03-31 08:18

  本文选题：烟草　切入点：干旱胁迫　出处：《植物营养与肥料学报》2017年02期

【摘要】：【目的】挖掘植物自身的抗旱能力是提高农业水分利用效率的有效措施。本研究通过比较水分胁迫处理下5个烤烟品种苗期根系发生和伸长以及叶片光合特性的变化,探讨烤烟抗旱能力差异的生理机制,为烟草生产的可持续发展提供理论依据。【方法】采用水培试验,设置对照和水分胁迫处理(添加2.5%PEG处理来模拟中度干旱),研究5个烤烟品种苗期的地上部和根系的生物量、一级和二级侧根的发生和伸长,利用Li-Cor 6400光合测定系统测定叶片的光合速率和气孔导度等参数,利用FLIR手持式红外热成像仪测定新展开叶的叶片温度,分析烟草抗旱能力差异明显的生理机制。【结果】水分胁迫条件下5个烤烟品种的生长差异明显。与对照处理相比,水分胁迫对大平板和农大202的生长影响不明显,但柳叶尖、金星6007和中烟100的地上部和根系生物量显著被抑制,降幅范围在66%~83%,达到差异极显著水平。水分胁迫抑制5个烤烟品种一级和二级侧根的伸长,但大平板和农大202的一级侧根数目和二级侧根密度显著增加,最终导致根系生物量没有下降;另外3个烟草品种柳叶尖、金星6007和中烟100的侧根发生增加趋势不明显。水分胁迫处理下抗旱能力强的大平板和农大202地上部生物量和叶片温度变化不明显,而叶片的净光合速率显著下降,但其降幅显著低于3个抗旱能力弱的烤烟品种。与对照处理相比,抗旱能力弱的柳叶尖、金星6007和中烟100叶片的气孔导度和蒸腾速率显著下降,叶片温度上升5~7℃。进一步的研究表明,PEG处理下耐旱能力强烤烟品种侧根数目的显著增加是地上部维持较强光合能力的主要原因。【结论】抗旱能力强的烟草品种苗期受到水分胁迫时其一级和二级侧根显著增加,进而能保持较高的光合特性。
[Abstract]:Objective: to explore the drought resistance of plants is an effective measure to improve the water use efficiency of agriculture.In this study, the physiological mechanism of drought resistance difference of five flue-cured tobacco varieties was studied by comparing the changes of root formation, elongation and photosynthetic characteristics of leaves in seedling stage under water stress.To provide the theoretical basis for the sustainable development of tobacco production. [methods] the biomass of shoot and root of 5 flue-cured tobacco varieties at seedling stage was studied by using water culture experiment and water stress treatment (adding 2.5%PEG treatment to simulate moderate drought).The occurrence and elongation of primary and secondary lateral roots, the photosynthetic rate and stomatal conductance of leaves were measured by Li-Cor 6400 photosynthetic system, and the leaf temperature of newly expanded leaves was measured by FLIR hand-held infrared thermal imager.The physiological mechanism of tobacco drought resistance difference was analyzed. [results] the growth difference of five flue-cured tobacco varieties under water stress was obvious.The effects of water stress on the growth of large flat plate and Nongda 202 were not obvious, but the aboveground and root biomass of willow leaf tip, Jinxing 6007 and Zhongyan 100 were significantly inhibited, and the decrease range was 6683cm, which reached the most significant level.Water stress inhibited the elongation of the first and second lateral roots of five flue-cured tobacco varieties, but the number of the first lateral roots and the density of the secondary lateral roots of the big flat and Nongda 202 increased significantly, resulting in no decrease of root biomass, and the willow tip of the other three tobacco varieties.The increasing trend of lateral roots of Venus 6007 and Zhongyan 100 is not obvious.Under water stress, the aboveground biomass and leaf temperature of big flat and Nongda 202 with strong drought resistance did not change significantly, while the net photosynthetic rate of leaves decreased significantly, but the decrease was significantly lower than that of three flue-cured tobacco varieties with weak drought resistance.Compared with the control, the leaf stomatal conductance and transpiration rate of willow leaf tip, Jinxing 6007 leaf and Zhongyan 100 leaf were significantly decreased, and the leaf temperature increased 5 ~ 7 鈩，

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