Physiological and ecological mechanisms of response and adaptation of horticultural plant resources to compound environmental stress

在各种严重的环境胁迫下，我们研究了园艺植物资源对UV-B辐射和盐胁迫的响应和适应机制。通过改变UV-B的照射时间、强度和波长范围等条件，研究了UV-B对5种蔬菜植物的生理生态响应。当UV-B到达地表时，将到达地表的UV-B分成大于300 nm的较短波长和较长波长的区域，300 nm以下的UV与可见光的增减几乎没有关系，表现出几乎固定的数量。对于甘蓝、菠菜、番茄、茄子和萝卜，UV-B是在暗期或光期照射的。并将结果与对照组进行比较。在黑暗时期的高强度UV-B使供试蔬菜叶片表面变成古铜色，叶缘向内卷曲，c…更多的是牵扯。可见光显示了减轻UV-B辐射损伤的作用。番茄对UV-B的敏感度最高，280~290 nm的UV-B对供试蔬菜的负效应非常强烈。UV-B辐照后的叶片弹性较差，水分含量也有所下降。对幼叶生长的影响较大。研究了在高盐环境下生长的三粒紫薇营养生长期的生理反应(生长、离子吸收和水分生理)和光合作用，以阐明其耐盐机制。水分胁迫和盐胁迫(300 MM)使其生长减慢，水分胁迫下的生长减慢幅度大于盐胁迫。盐胁迫下叶片对Na~+、Cl~+的吸收高于水分胁迫，Na~+/K~+比值也高于对照叶片的水势，水分胁迫>盐胁迫>盐胁迫。在大气CO_2浓度为350ppm的条件下，对照、水分胁迫和盐胁迫的光合作用气孔限制率分别为对照的33%、52%和44%，光饱和光合作用速率在水分胁迫下下降，但在盐胁迫下没有变化。在盐胁迫下，由于气孔部分关闭，限制了CO_2的供应，从而降低了光合作用速率。然而，光合作用的光和暗反应系统在盐胁迫下受到保护。同时，由于气孔的关闭和暗反应系统能力的降低，水分胁迫下的光合作用速率降低。较少

In various serious environmental stresses, we investigated mechanism of response and adaptation of the horticultural plant resources to ultraviolet-B radiation and salt stresses.1. By changing the various irradiation conditions such as exposure time, strength, and wavdength regions of UV-B, what kind of failure was generant to the plant by the UV-B irradiation, the physiological and ecological responses of five vegetable plant species to UV stress were investigated.When UV-B, which reaches the surface, was divided into shorter wavelength and longer wavelength regions than 300 nm, UV of 300nm or less was not related to increase and decrease of visible light, and it showed the almost fixed quantity.For cabbage, spinach, tomato, eggplant, and radish, UV-B was irradiated in the dark period, or light period, and the results was compared with the control. High-intense UV-B in the dark period made the surface of tested vegetable leaves into the bronze, and the leaf margin curled inside, and c … More ontracted. Visible light showed the effect that eases the damage by the UV-B irradiation. Tomato had the most UV-B sensitivity 280〜290nm of UV-B gave very intensive negative effects to the vegetables tested. Leaves that UV-B was irradiated had lacked the flexibility, and also decreased on the water content. The effect on the growth was strongly observed in younger leaves.2. Physiological response (growth, absorption of ions and water physiology) and photosynthesis in the vegetative growth stage of Aster tripolium L.Which was able to grow under the hyper saline environment, were investigated in order to clarify the salt tolerance mechanism.The growth lowered by water stress, and NaCl stress (300mM), and it decreased more in water stress than NaCl stress. Absorption of Na^+ and Cl^+ ino the leaves was higher in the NaCl stress than water stress, and the Na+/K+ ratio was also higher Water potential of the leaves in control, water stress, and NaCl stress lowered in order. Turgor pressure was almost same in control and NaCl stress, and lowered in water stress.Under the atmosphere CO_2 condition (350 ppm) the rates of stomatal limiting of photosynthesis in control, water stress, and salt stress were 33%, 52% and 44% of control respectively Without the stomatal limiting the light saturation photosynthetic rate was decreased in the water stress, but not in the NaCl stress. The photosynthetic rate was decreased because of limiting the supply of CO_2 through the partial closure of the stoma under NaCl stress. Light and dark reaction systems of photosynthesis, however, were protected in NaCl stress. In the meantime, the photosynthetic rate in water stress was lowered by closure of the stoma and decrease in the ability of the dark reaction system. Less