Effects of UV-B Radiation on the Aerenchyma of Rice in Yuanyang Terrace

Purpose The effects of different intensity levels 0, 5.0 and 10 kJ/(m²·d) of UV-B radiation on the root, stem aeration tissue of local rice (Oryza sativa L.) cultivars ‘Baijiaolaojing’ in Yuanyang terrace were investigated at full heading stage in situ field cultivation conditions.

Method The traditional paraffin slicing method was used to prepare the cross-section of rice root and stem base, and the Leica DMLB2 microscope was used to photograph and measure the size of the aerated tissue in rice roots and stems.

Result The 5.0 and 10.0 kJ/(m²·d) UV-B radiation caused a significant increase of rice root cross-cutting area, and the 5.0 kJ/(m²·d) UV-B radiation caused the area of vascular bundle in internal root significantly increasing. The area of the stem wall of inverted 1, 2 and 3 eustipes were significantly reduced by 5.0 kJ/(m²·d) UV-B radiation, but in inverted 4 eustipes was significantly increased, and the area of the medullary cavity significantly reduced in inverted 3 and 4 eustipes. After the treatment of 5.0 kJ/(m²·d) UV-B radiation, the area of the gas cavity significantly increased in inverted 1, 2, 3 and 4 eustipes, and the air cavity area under the treatment of 10.0 kJ/(m²·d) UV-B radiation significantly increased in inverted 3 eustipes, and significantly reduced in inverted 4 eustipes. After UV-B radiation, the areas of vascular bundle in different eustipes had different trends, and the area of vascular bundle in inverted 4 eustipes increases significantly.

Conclusion UV-B radiation enhancement can lead to significant changes Yuanyang terrace rice’s aerenchyma, and can significantly increase vascular bundle area, and gas cavity area of internode, stem wall transverse area ratio.