Comparison of pretreatment, preservation and determination methods for foliar pH of plant samples. (28th January 2022)

• Record Type: Journal Article
• Authors: Liu, Sining; Chen, Jiashu; Han, Wenxuan
• Editors: Zhang, Wen-Hao
• Is Part Of: Journal of plant ecology. Volume 15:Number 4(2022)
• Page Start: 673
• Page End: 682
• Publication Date: 2022-01-28
• Subjects: green/senesced leaf -- leaf pH -- plant functional traits -- sample preservation -- specification/standard/protocol -- leaf water ratio -- transformation/conversion equation; 绿叶/落叶 -- 叶片pH值 -- 植物功能属性 -- 叶片样品保存方式 -- 规范/标准 -- 叶与水混合比例 -- 转换方程; Plant ecology -- Periodicals; Phytogeography -- Periodicals; 581.705
• DOI: 10.1093/jpe/rtac012
• Languages: English
• ISSNs: 1752-9921

Abstract

Abstract: To compare current methods of pretreatment/determination for plant foliar pH, we proposed a method for long-period sample preservation with little interference with the stability of foliar pH. Four hundred leaf samples from 20 species were collected and four methods of pH determination were used: refrigerated (stored at 4 °C for 4 days), frozen (stored at −16 °C for 4 days), oven-dried and fresh green-leaf pH (control). To explore the effects of different leaf:water mixing ratio on the pH determination results, we measured oven-dried green-leaf pH by leaf:water volume ratio of 1:8 and mass ratio of 1:10, and measured frozen senesced-leaf pH by mass ratio of 1:10 and 1:15. The standard major axis regression was used to analyze the relationship and the conversion equation between the measured pH with different methods. Foliar pH of refrigerated and frozen green leaves did not significantly differ from that of fresh green-leaf, but drying always overrated fresh green-leaf pH. During the field sampling, cryopreservation with a portable refrigerator was an advisable choice to get a precise pH. For long-duration field sampling, freezing was the optimal choice, and refrigeration is the best choice for the short-time preservation. The different leaf:water mixing ratio significantly influenced the measured foliar pH. High dilution reduced the proton concentration and increased the measured pH. Our findings provide the conversion relationships between the existing pretreatment and measurement methods, and establish a connection among pH determined by different methods. Our study can facilitate foliar pH measurement, thus contributing to understanding of this interesting plant functional trait.