马铃薯不同耐旱品系管栽苗及其根尖显微结构对干旱胁迫的响应

Responses of PVC-pipe Seedlings and Their Root Tip Microstructures of Different Drought-Resistant Potato Varieties to Drought Stress

从国际马铃薯中心(International Potato Center,CIP)引进的资源中选取了两个生育期相同,耐旱性存在差异的马铃薯耐旱品种(C16:CIP397077.16和C119:CIP398098.119)为材料,采用不限制根系生长的管栽模式,系统分析了不同水分胁迫下,这两个品种从外部形态特征,抗逆生化指标到根尖显微和超微结构的变化。结果表明:干旱胁迫会导致两个品种的根长、根活力、过氧化氢酶活力、可溶性糖和脯氨酸含量的显著升高,株高、叶片与茎杆夹角、根系相对含水量的显著降低,根尖中柱结构和细胞壁完整性发生显著改变,说明管栽模式对马铃薯根系响应干旱胁迫的研究较为理想。与C16相比,C119的绝大部分上述指标在正常浇水和不同水分处理下均表现出显著的优势,对干旱胁迫表现出了更好的适应性。此外,在干旱胁迫下,两个马铃薯品种的木质部导管直径变小、数量减少,且抗旱性更强的C119的木质部导管数量明显少于C16,这说明马铃薯也可能通过改变水分运输组织结构的策略来抵御干旱胁迫。

Two varieties of potato(C16:CIP397077.16and C119:CIP398098.119)with the same growth period but different drought tolerance were selected from the resources in the International Potato Center(CIP).Potatoes were planted in the PVC pipes where the root growth would not be restricted.The morphological characteristics,stress-resistant biochemical indicators,root tip microstructure,and ultrastructure of two potato varieties were systematically analyzed under different drought stress conditions.The results showed that drought stress led to significant increases in root length,root vigor,catalase activity,content of soluble sugar and proline,significant decreases in plant height,leaf-to-stem angle and root relative water content,and some visible changes in the core structure and the integrity of cell wall in the root tip of two varieties.These results indicated PVC-pipe-planting was ideal for studying potato root response to drought stress.Most of above indicators in C119presented significantly better performance than C16no matter under normal watering condition or drought stress treatment,i.e.,C119had better adaptability to drought stress.In addition,the diameter and number of axillary xylem vessels of both varieties decreased under drought stress;moreover,the number of axillary xylem vessels of C119with better drought resistance was significantly less than that of C16,suggesting that the potato may also resist drought stress by changing the structure of the water transport organization.