Effects of drought stress on leaf structure and root morphology of almond rootstock seedlings

Objective Through a water controlled pot experiment, the leaf anatomical structure and root morphological characteristics of six different rootstock resources of almonds were studied in response to moderate soil drought stress with a period of 60 d. The aim was to screen out almond rootstock resources with strong drought resistance and provide drought resistant materials for the development and utilization of excellent drought resistant rootstock resources.

Method Using two local peach almond resources (SC64, SC28), three almond resources (SC30, SC3 and SC47) and peach as experimental materials, a total of related indicators were obtained through optical microscope observation and root scanning treatment, and biological statistical analysis was conducted.

Result Under moderate drought stress, structural indicators such as leaf thickness, upper epidermal cell thickness, mesophyll cell porosity, and specific leaf area (SLA) of SC3, SC47 and peach decreased to varying degrees (P < 0.05); meanwhile, drought stress promoted an increase in root to shoot ratio and root growth (P < 0.05). Through principal component analysis, five representative indicators were selected, including upper epidermal cell thickness, underground biomass, specific gravity of fine root biomass with a diameter greater than 0.5 mm, mesophyll cell compactness, and SLA value. The results of membership function indicated that their drought resistance ability was ordered as SC30 > SC47 > SC3 > SC28 > SC64 > peach.

Conclusion The drought resistance of almond resources is stronger than that of peach almond and peach resources. Peach almond resources are at a moderate drought resistance level, while peach is the most sensitive to soil drought and has weaker drought resistance.