花生部分根系干燥对干旱胁迫的缓解效应

本研究基于植物旱生原理，对花生植株进行部分根系干燥（PRD）刺激，以期调节花生旱生反应，增强植 株后期对干旱胁迫的防御能力。采用隔板（P1）、分容器（P2）和凡士林（P3）3种分根方法，将根系分为两侧根区并进 行4轮根区交替灌溉，一侧根区保持40%田间持水量，另一侧根区正常浇水（75%田间持水量），研究PRD诱导的花 生旱生反应相关生理指标的变化。结果表明：与对照相比，3种PRD处理根冠比均增加，叶片细胞溶质浓度值CFT增 加，ΔCFT分别为43.1（P1）、65.1（P2）和49.6（P3）osmol∙m-3，水势和渗透势降低，膨压显著增大；O2·-含量增加2~3倍， 超氧化物歧化酶（SOD）活性显著增加并在复水后保持较高的活性；PRD缩短离体叶片气孔关闭时间，延长水分蒸发 时间，复水后光合势能增强，叶片和根系中Gdi-15 基因表达增强2~7倍。为进一步研究PRD预处理对干旱胁迫的 缓解作用，以凡士林分根法进行PRD预处理的干旱试验，设3个处理：正常浇水（Control，75%田间持水量）、干旱胁 迫（D，35%田间持水量）和PRD预处理的干旱胁迫（DP），分析比较各处理间生理指标的变化。结果表明：与D处理 相比，DP处理叶片相对含水量由51.68%增加到61.07%，脯氨酸含量由4328.72μg g-1FW减少到2104.50 μg∙g-1FW， MDA和O2·-含量均降低，POD活性由592.46降低到217.68 U∙g-1FW。3种PRD处理方式都能诱导花生植株产生旱生 反应，以凡士林法效果最佳。PRD预处理可对植株进行干旱驯化，使植株再次感知干旱胁迫时表现迅速的生理防 御和快速的生理恢复能力。

Alleviating effect of partial rootzone drying on xerophytophysiological responses in peanut plants under drought stress

A stimulus of partial rootzone drying (PRD) to plant roots can induce xerophytophysiological responses, and improve drought resistance and the defense ability under subsequent drought stress. Shelve (P1), double container (P2) and vanseline (P3) were set to separate the peanut roots into two rootzones before PRD treatment. Two rootzones were alternatively irrigated four times, one side of rootzone kept 40% of field capacity, the other normally irrigated with 75% of field capacity. Some physiological indexes of peanut xerophytic reaction induced by PRD were studied. The results showed that PRD treatments increased root/shoot ratio, accumulated cytosol solutes actively with ΔCFT value of P1, P2 and P3 treatments at 43.1, 65.1 and 49.6 osmol m-3 respectively. Water potential and osmotic potential reduced and turgor potenial increased significantly. O2·-content increased by 2-3 times and SOD activity increased significantly and remained high after rewatering. PRD shortened stomatal closing time of detached leaves with prolonged water evaporation time, improved leaf photosynthesis after rewatering, and Gdi-15 gene expression in leaves and roots was induced by 2 to 7 times. Further experiment was designed to study the effect of pre-PRD treatment on subsequent drought stress, 3 treatments were normal irrigation with 75% of field capacity (Control), drought stress with 35% of field capacity (D) and subsequent drought stress with pre-PRD treatment (DP). Compared with D treatment, leaf relative water content in DP treatment increased from 51.68% to 61.07%. Proline accumulation in DP treatment reduced to 2104.50 μg∙g-1FW compared with 4328.72μg∙g-1FW in D treatment, pre- PRD priming decreased MDA and O2·-content, meanwhile POD activity decreased from 592.46 to 217.68U∙g-1FW. In conclusion, all three ways of PRD treatment induced xerophytophysiological regulation of which PRD treatment used by vanseline was the best. Pre-PRD treatment could acclimate the plants to drought, so that the plants showed rapid physiological defense and recovery ability when sensing drought stress again.