抗旱糜子根系生长特性及叶片表皮结构对水分胁迫的响应

The Responses of Root Growth Characteristics and Leaf EpidermalStructure of Drought-Resistant Broomcorn Millet to WaterStress

以2个抗旱性不同的糜子品种陇糜4号和晋黍7号为材料,采用全生育期防雨棚盆栽方式,设置正常供水(CK,土壤含水量为田间持水量的65%~75%)、轻度水分胁迫(55%~65%)、中度水分胁迫(45%~55%)和重度水分胁迫(35%~45%)4个处理,观察不同抗旱性糜子品种叶片显微结构,比较整个生育期水分胁迫对不同抗旱性糜子品种根长、根总表面积、根冠比和根系活力的差异。结果表明,轻度水分胁迫处理提高了2个糜子品种的根长、根总表面积、根冠比和根系活力;重度水分胁迫下,根长、根表面积、根冠比及根系活力均随着水分胁迫程度的加剧而减小,且显著降低了糜子的根冠比和根系活力,陇糜4号和晋黍7号成熟期2年的根冠比分别平均降低11.90%和24.38%,根系活力分别平均降低18.73%和58.11%,且对水分敏感的晋黍7号的根系活力受抑制程度显著大于陇糜4号。通过扫描电镜研究发现,相同倍数下,抗旱性强的品种气孔密而多,且上表面分布有较多的长细胞、较密集的蜡质,同时有硅质细胞的存在。抗旱性品种陇糜4号在重度水分胁迫下各指标降幅均低于晋黍7号,良好的根系形态、较强的根系活力及硅质细胞的存在是其能较好适应干旱环境的主要因素。

Longmi 4 and Jinshu 7 were used as materials and anti-canopy was used throughout the growthperiod.Four different water stress treatments were carried out including normal water supply(CK,the soil watercontent is 65%-75%of the field water holding capacity),mild water stress(55%-65%),moderate water control(45%-55%)and severe stress(35%-45%)of whole broomcorn millet growth stage,the leaf microstructureofdifferent drought-resistant broomcorn millet varieties was observed,root length,total root surface area,root-shoot ratio,root activity of different drought-resistant millet varieties were compared under whole growthperiod.The results showed that root length,total root surface area,root-shoot ratio and root activity of twomillet varieties were increased under mild water stress.However,root length,root surface area,root-shoot ratioandroot activity were decreased as the water stress increasing,and the root-shoot ratio and root activity of broomcornmillet significantly reduced under severe water stress.The root-shoot ratio of Longmi 4 and Jinshu7weredecreased by 11.90%and 24.38%,respectively,the root activities were decreased by 18.73%and 58.11%onaverage in maturity period under severe water stress,and the degree of root activity inhibition of Jinshu7wassignificantly greater than that of Longmi 4.In the same multiple,by scanning electron microscopy,the varietieswith strong drought resistance had dense stomata,long cells,dense waxy,and had siliceous cells on theuppersurface at the same ratio by stem observation method.In short,all indexes of Longmi 4 had a lower decreaseunder severe water stress than Jinshu 7 because it had good root morphology,strong root vitality and siliceouscells for adapting to drought environment.