干旱及复水对谷子苗期根系形态特征及叶片解剖结构的影响

Effect of Drought Stress and Rewatering on Root Morphological Characteristics and Leaf Anatomical Structure of Foxtail Millet

本试验选用抗旱性强的谷子品种济谷16和旱敏感谷子品种鲁谷1号为材料,设置盆栽试验,于出苗15 d时停止浇水进行干旱胁迫处理,并于9 d后复水,研究不同抗旱性谷子品种叶片以及根系形态指标对干旱-复水的响应。结果表明:(1)与CK相比,干旱胁迫导致两个谷子品种的根分枝数、根尖数和根体积显著减少;复水后,济谷16的根尖数显著增加(P<0.05),而鲁谷1号的根尖数进一步显著降低。济谷16的根分枝数在复水后的增加幅度大于鲁谷1号。(2)干旱胁迫下,两个品种叶片泡状细胞面积缩小,叶片厚度下降;复水后济谷16泡状细胞面积与CK相当,而鲁谷1号仍显著小于CK(P<0.05)。(3)干旱胁迫下济谷16下表皮气孔密度增加,上表皮气孔密度减小,且均与CK差异显著(P<0.05);复水后,上表皮气孔密度略有增加但仍低于CK,下表皮气孔密度降低至CK水平。干旱胁迫下鲁谷1号上、下表皮气孔密度较CK均显著下降(P<0.05);复水后,上表皮气孔密度继续降低,而下表皮气孔密度显著增加至略高于CK水平。干旱胁迫后济谷16上、下表皮气孔长度无显著变化,复水后较CK和干旱处理均显著增加;鲁谷1号上表皮气孔长度显著减小(P<0.05),复水后仍继续减小,但较干旱处理差异不显著;鲁谷1号下表皮气孔长度较CK增加但差异不显著,复水后继续增长,显著高于CK。综上所述,干旱胁迫后复水,抗旱品种济谷16通过根分枝数和根尖数的增加以及叶片泡状细胞面积、气孔密度快速恢复,使其表现出更强的形态适应性和自我调节能力。

A drought-resistant variety Jigu 16 and a drought-sensitive variety Lugu 1 were used as materi-als to study the response of leaf and root morphological indicators to drought stress and rewatering with pot ex-periment.Drought stress treatment was performed by stop watering 15 days after sprout,and then rewatering 9 days later.The results were as follows.(1)Compared with normal water supply treatment(CK),the number of lateral roots and root tips and the root volume of the two varieties decreased significantly under drought stress.After rewatering,the number of root tips of Jigu 16 increased significantly,while that of Lugu 1 further decreased(P<0.05).The number of lateral roots of Jigu 16 increased more than that of Lugu 1 after rewater-ing.(2)Under drought stress,the area of bulliform cells in leaves and the leaf thickness of the two varieties decreased.After rewatering,the bulliform cell area of Jigu 16 recovered to the similar level of CK,while that of Lugu 1 was still significantly smaller compared to CK(P<0.05).(3)Under drought stress,the stomatal den-sity in the lower epidermis of Jigu 16 increased,while the stomatal density in the upper epidermis decreased,and the difference was significant(P<0.05)compared with CK;after rehydration,the upper epidermal stoma-tal density increased slightly but was still lower than CK,and that in lower epidermal stomatal density de-creased to CK level.Stomatal density of upper and lower epidermis of Lugu 1 decreased after drought stress.Af-ter rehydration,the upper epidermal stomatal density still decreased slightly,but the lower epidermal stomatal density increased significantly,slightly higher than CK.There was no significant change in stomatal length in upper and lower epidermis of Jigu 16 after drought stress.After rehydration,it increased significantly compared with CK and drought treatment.Stomatal length of upper epidermis of Lugu 1 decreased significantly(P<0.05).After rehydration,it still decreased slightly,but the difference was not significant compared with drought treatment.The stomatal length of lower epidermis decreased but the difference was not significant com-pared with CK,and continued to increase after rehydration,which was significantly higher than CK.Jigu 16 showed stronger morphological adaptability and self-regulation ability under drought stress,and its drought tol-erance was stronger than Lugu 1.