In this study, we examined responses of maize hybrids differing in susceptibility to soil compaction and drought in the case of their separate or combined action. We ran field and greenhouse experiments and determined effects on grain yield, biomass, weight of 1000 grains, shoot and roots dry matter (DM), shoot-to-roots ratio, harvest index, plant height, emergence index, leaf area and greening and root number and length. Individual and combined effects of both stresses were observed in the field and greenhouse. Compared with plants growing in loose soil and optimal irrigation (LI), the resistant hybrids in treatments HI, LD and HD showed a smaller reduction in GY, BY, S, R, R_N and R_L than the sensitive. In both groups, stress influence on HA, W-1000, LA and SPAD was smaller and the differences were insignificant. Compared with LI treatment, the roots of LD, HI and HD increased their DM, number and length in the upper level of the soil profile and the number of roots developed at 0–30° and 30–60° in relation to the root main axis. Analysis of those traits in the hybrids resistant and sensitive to both stress factors enabled to explain a defence response. Our study demonstrated that soil compaction and soil drought, which usually occurs simultaneously, caused significant changes in components of plant yield and showed plant plasticity in response to environmental factors under natural conditions.

中文翻译：

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土壤干旱对压实土壤下杂交玉米 (Zea mays L.) 生长和产量的影响

在这项研究中，我们研究了玉米杂交种在单独或联合作用的情况下对土壤压实和干旱的敏感性不同的反应。我们进行了田间和温室试验，确定了对谷物产量、生物量、1000 粒谷物的重量、茎和根干物质 (DM)、茎根比、收获指数、株高、出苗指数、叶面积和绿化率的影响，以及根数和长度。在田间和温室中观察到两种胁迫的单独和综合影响。_{与生长在疏松土壤和最佳灌溉（LI）中的植物相比，HI、LD 和 HD 处理的抗性杂交种表现出较小的 GY、BY、S、R、R N}和 R _L降低比敏感。在两组中，应激对HA、W-1000、LA和SPAD的影响较小，差异不显着。与 LI 处理相比，LD、HI 和 HD 根系在土壤剖面上层的 DM、数量和长度增加，根系主根在 0~30°和 30~60°发育的根数增加轴。分析对这两种压力因素具有抵抗力和敏感性的杂种的这些特征能够解释防御反应。我们的研究表明，通常同时发生的土壤压实和土壤干旱会导致植物产量的组成部分发生显着变化，并显示出植物在自然条件下对环境因素做出反应的可塑性。