This study aimed to investigate the differences in growth and physiological characteristics of seedlings from five predominant Camellia oleifera cultivars in Hunan Province under acidic purple soil, alkaline purple soil, and red soil (control) conditions, so as to provide a theoretical basis for ecological adaptability evaluation, cultivar selection, and targeted soil improvement of C. oleifera in purple soil regions of Hunan.

A pot experiment was conducted using red soil as the control. Growth, physiological, and biochemical indices of three-year-old seedlings of five cultivars (‘Huashuo’@@@, ‘Huajin’@@@, ‘Huaxin’@@@, ‘Xianglin 210’@@@, and ‘Hengdong Datao No.2’@@@) were measured across three soil types. The data were comprehensively evaluated using membership function method and principal component analysis.

The acidic purple soil was more favorable for the growth of C. oleifera, with the average membership function values of growth indicators for all cultivars being higher than those in the red soil and alkaline purple soil. Under acidic soil conditions, ‘Huashuo’@@@ and ‘Hengdong Datao No.2’@@@ showed the most comprehensive performance, with generally desirable growth, physiological, and biochemical parameters, although their chlorophyll content was comparatively lower. In alkaline soil, both ‘Huashuo’@@@ and ‘Huaxin’@@@ exhibited elevated antioxidant enzyme activities; however, ‘Huashuo’@@@ displayed the highest malondialdehyde (MDA) content, indicating substantial membrane damage and poor adaptability. In contrast, ‘Huaxin’@@@ maintained lower MDA levels and achieved higher membership function rankings, reflecting superior membrane stability and stress tolerance. Principal component analysis revealed that all cultivars performed better in acidic soil than in the other soil types. ‘Hengdong Datao No. 2’@@@ and ‘Huaxin’@@@ performed well in both red soil and acidic purple soil, whereas ‘Huajin’@@@ and ‘Huaxin’@@@ demonstrated relatively better adaptability in alkaline purple soil.

Comprehensive analysis of all measured indicators revealed that acidic purple soil was the most suitable for C. oleifera growth, with cultivars grown in this soil type occupying the top five positions in the overall ranking. The order of soil adaptability was determined as: acidic purple soil>red soil>alkaline purple soil. ‘Hengdong Datao No. 2’@@@ and ‘Huaxin’@@@ exhibited the best performance in both acidic purple soil and red soil, while ‘Huajin’@@@ and ‘Huaxin’@@@ showed relatively superior adaptation in alkaline purple soil. Considering the overall performance across all three soil types, ‘Huaxin’@@@ demonstrated the strongest comprehensive adaptability.