关键词: 尾草履虫, 尾草履虫, 急性毒性, 抗氧化酶, 纳米氧化锌, 纳米二氧化钛

Abstract: The paper aims to clarify the correlation between SPAD value and photosynthetic pigment content in sugarbeet leaves, and provide a basis for nitrogen nutrition diagnosis of sugarbeet. The leaf SPAD value, chlorophyll a, chlorophyll b, total chlorophyll content and carotenoid content in leaves of sugarbeet varieties at seedling stage were measured, and the differences of SPAD value, chlorophyll content and the correlation of SPAD value with different photosynthetic pigments were analyzed. The results showed that there were differences in chlorophyll a, chlorophyll b, total chlorophyll, carotenoid and SPAD values among varieties, chlorophyll a content> chlorophyll b content> carotenoid content in sugarbeet leaves. There was a positive correlation between leaf SPAD value and chlorophyll content, in which the correlation between total chlorophyll content and SPAD value was the highest (r=0.7766), followed by the that between chlorophyll a, chlorophyll b content and SPAD value, while the correlation between carotenoid and SPAD value was the lowest (r=0.5704). Therefore, it is feasible to use SPAD value to predict the content of chlorophyll in beet leaves and diagnose plant nutrition rapidly and nondestructively in beet production.