Institute of Grassland Science, Northeast Normal University, Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun, China.
Department of Botany, University of Peshawar, Peshawar, 25120, Pakistan.
BMC Plant Biol. 2023 Sep 7;23(1):414. doi: 10.1186/s12870-023-04429-y.
The application of germination models in economic crop management makes them extremely useful for predicting seed germination. Hence, we examined the effect of varying water potentials (Ψs; 0. - 0.3, - 0.6, - 0.9, - 1.2 MPa) and temperatures (Ts; 20, 25, 30, 35, 40 °C) on maize germination and enzymatic antioxidant mechanism. We observed that varying Ts and Ψs significantly influenced germination percentage (GP) and germination rate (GR), and other germination parameters, including germination rate index (GRI), germination index (GI), mean germination index (MGI), mean germination time (MGT), coefficient of the velocity of germination (CVG), and germination energy (GE) (p ≤ 0.01). Maximum (87.60) and minimum (55.20) hydro-time constant (θH) were reported at 35 °C and 20 °C, respectively. In addition, base water potential at 50 percentiles was highest at 30 °C (15.84 MPa) and lowest at 20 °C (15.46 MPa). Furthermore, the optimal, low, and ceiling T (To, Tb and Tc, respectively) were determined as 30 °C, 20 °C and 40 °C, respectively. The highest θT1 and θT2 were reported at 40 °C (0 MPa) and 20 °C (- 0.9 MPa), respectively. HTT has a higher value (R2 = 0.43 at 40 °C) at sub-optimal than supra-optimal temperatures (R2 = 0.41 at 40 °C). Antioxidant enzymes, including peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione peroxidase (GPX), increased with decreasing Ψs. In contrast, CAT and POD were higher at 20 °C and 40 °C but declined at 25, 30, and 35 °C. The APX and GPX remained unchanged at 20, 25, 30, and 40 °C but declined at 35 °C. Thus, maintaining enzymatic activity is a protective mechanism against oxidative stress. A decline in germination characteristics may result from energy diverting to anti-stress tools (antioxidant enzymes) necessary for eliminating reactive oxygen species (ROS) to reduce salinity-induced oxidative damage. The parameters examined in this study are easily applicable to simulation models of Z. mays L. germination under extreme environmental conditions characterized by water deficits and temperature fluctuations.
在经济作物管理中，发芽模型的应用使得它们在预测种子发芽方面非常有用。因此，我们研究了不同水势（Ψs；0. -0.3、-0.6、-0.9、-1.2 MPa）和温度（Ts；20、25、30、35、40°C）对玉米发芽和酶抗氧化机制的影响。我们观察到，Ts 和 Ψs 的变化显著影响发芽率（GP）和发芽率（GR）以及其他发芽参数，包括发芽率指数（GRI）、发芽指数（GI）、平均发芽指数（MGI）、平均发芽时间（MGT）、发芽速度系数（CVG）和发芽能量（GE）（p≤0.01）。在 35°C 和 20°C 时，报道的最大（87.60）和最小（55.20）水时常数（θH）。此外，50%的基础水势在 30°C 时最高（15.84 MPa），在 20°C 时最低（15.46 MPa）。此外，最优、低和最高 T（To、Tb 和 Tc，分别）分别确定为 30°C、20°C 和 40°C。θT1 和 θT2 的最高值分别出现在 40°C（0 MPa）和 20°C（-0.9 MPa）。在亚最佳温度下，HTT 的值（在 40°C 时为 0.43）高于最佳温度（在 40°C 时为 0.41）。抗氧化酶，包括过氧化物酶（POD）、过氧化氢酶（CAT）、超氧化物歧化酶（SOD）、抗坏血酸过氧化物酶（APX）和谷胱甘肽过氧化物酶（GPX），随着 Ψs 的降低而增加。相反，CAT 和 POD 在 20°C 和 40°C 时较高，但在 25、30 和 35°C 时下降。APX 和 GPX 在 20、25、30 和 40°C 时保持不变，但在 35°C 时下降。因此，保持酶活性是一种针对氧化应激的保护机制。发芽特性的下降可能是由于能量转移到必需的抗应激工具（抗氧化酶）上，以消除活性氧（ROS），从而减少盐胁迫引起的氧化损伤。本研究中检查的参数很容易适用于以水分亏缺和温度波动为特征的极端环境条件下玉米发芽的模拟模型。
