Figure 22.23 A flooded maize field. Flooding in the US Midwest in 1993 resulted in an estimated 33% reduction in yield compared with 1992
Figure 22.23 A flooded maize field. Flooding in the US Midwest in 1993 resulted in an estimated 33% reduction in yield compared with 1992
图22.1 Many factors determine how plants respond to environmental stress: the genotype and development circumstances of the plant, the duration and severity of the stress, the number of times the plant is subjected to stress, and any additive or synergistic effects of multiple stresses. Plants response to stress through a variety of mechanisms. Failure to compensate for a severe stress can result in plant death
图22.1 Many factors determine how plants respond to environmental stress: the genotype and development circumstances of the plant, the duration and severity of the stress, the number of times the plant is subjected to stress, and any additive or synergistic effects of multiple stresses. Plants response to stress through a variety of mechanisms. Failure to compensate for a severe stress can result in plant death
2. 逆境伤害性质 1) 直接伤害（direct stress injury） 2) 间接伤害（indirect stress injury） 严重的逆境，短时间作用产生的对植物生命结构 （蛋白质、膜、核酸等）的不可逆伤害。 这时植物还来不及发生代谢上的改变。 如高温烫伤、冰冻等。 较弱的逆境，长时间作用，可以把原来的弹 性胁变转化为塑性胁变，造成伤害。 主要是代谢紊乱
2. 逆境伤害性质 1) 直接伤害（direct stress injury） 2) 间接伤害（indirect stress injury） 严重的逆境，短时间作用产生的对植物生命结构 （蛋白质、膜、核酸等）的不可逆伤害。 这时植物还来不及发生代谢上的改变。 如高温烫伤、冰冻等。 较弱的逆境，长时间作用，可以把原来的弹 性胁变转化为塑性胁变，造成伤害。 主要是代谢紊乱
图22.3 . Plants respond to both as collections of cells and as whole organisms. Stress constitute environmental signal is communicated within cells and throughout the plants. Transduction of environmental signals typically results in altered gene expression at in the cellular level, which in turn influence metabolism and development of the whole plant
图22.3 . Plants respond to both as collections of cells and as whole organisms. Stress constitute environmental signal is communicated within cells and throughout the plants. Transduction of environmental signals typically results in altered gene expression at in the cellular level, which in turn influence metabolism and development of the whole plant
3. 植物对逆境的适应与抵抗 抗性=胁强 / 胁变 植物对逆境的适应与抵抗能力，称为抗逆性（hardiness） 植物抗逆性 强弱取决于 遗传潜力 抗逆锻炼 指植物在逆境下，逐渐形成了对逆境的适 应与抵抗能力。这一过程称为抗逆锻炼。 胡杨
3. 植物对逆境的适应与抵抗 抗性=胁强 / 胁变 植物对逆境的适应与抵抗能力，称为抗逆性（hardiness） 植物抗逆性 强弱取决于 遗传潜力 抗逆锻炼 指植物在逆境下，逐渐形成了对逆境的适 应与抵抗能力。这一过程称为抗逆锻炼。 胡杨