Physiological and biochemical changes in leaf abscission of Cyclocarya paliurus stem segments in vitro

• Published in: Plant cell, tissue and organ culture Vol. 155; no. 3; pp. 773 - 783
• Main Authors: Li, Qiu-Ying, Wang, Shuang, Wu, Gao-Yin, Tan, Ya, Liu, Ying-Ying, Yuan, Cong-Jun, Geng, Shuang-Gui, Liu, Ying-Liang
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.12.2023; Springer Nature B.V
• Subjects: Abscission; Accumulation; Biomedical and Life Sciences; carotenoids; Catalase; Cell walls; Cellulase; Chlorophyll; Correlation analysis; Cyclocarya paliurus; Cytology; Degradation; endo-1,4-beta-glucanase; energy; Enzymatic activity; Enzymes; extracellular space; Hydrogen peroxide; leaf abscission; Leaves; Life Sciences; Lignin; Metabolites; Original Article; Pectinase; Peroxidase; phenotype; Phenotypes; photosynthesis; Physiology; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Plant Sciences; Plant tissues; polygalacturonase; Proteins; Rupturing; Segments; Stems; Stress (physiology); Sugar; sugar content; sugars; Superoxide dismutase; Vascular tissue; In vitro culture; Physiological and biochemical; Stem segment; Leaf abscission
• ISSN: 0167-6857; 1573-5044
• DOI: 10.1007/s11240-023-02598-0

Leaf abscission of Cyclocarya paliurus stem segments is extremely serious in vitro and seriously hinders the rapid propagation process of C. paliurus. To explore the physiological and biochemical responses of leaf abscission of C. paliurus stem segments in vitro, the emerged leaves of C. paliurus stem segments were cultured for 22 days (T0) in vitro; leaves germinated for 27 days (T1) and leaves exfoliated for ≥ 32 days (T2) were used as materials, and the phenotype and changes in abscission zone (AZ) cell tissue morphology of the leaf abscission process were observed; moreover, the contents of photosynthetic metabolites, H 2 O 2 levels, anti-reverse enzyme and cell wall modification enzyme activities and lignin contents were determined. With the development of C. paliurus leaves, the volume of AZ cells gradually increased; subsequently, the intercellular space of AZ cells and vascular cells was degraded, and the cell walls ruptured, which resulted in leaf abscission. During the process of leaf abscission, the contents of soluble sugar and chlorophyll a/b first increased and then decreased, but there was no significant difference in soluble sugar content between T2 and T1; the contents of carotenoid, soluble proteins, H 2 O 2 and lignin and the activities of superoxide dismutase (SOD), pectinase and cellulase increased gradually, but catalase (CAT) activity gradually decreased; in addition, the peroxidase (POD) activity decreased sharply and then increased sharply. Correlation analysis showed that the chlorophyll content was significantly positively correlated with soluble sugar content; the contents of soluble protein, H 2 O 2 , and lignin, the activities of SOD, pectinase, and cellulase were extremely significantly positively correlated with each other, and they were extremely significantly negatively correlated with CAT activity. Therefore, the cell wall rupture of AZ cells and vascular tissue was the cytological basis of leaf abscission in C. paliurus , and its leaf abscission was not related to the accumulation of energy substances. The leaf may be subject to some stress, stimulate anti-reverse enzyme reactions, promote the accumulation of H 2 O 2 in leaves, enhance pectinase and cellulase activities, and accelerate the degradation of the cell walls with AZ cells and vascular tissues, which results in leaf abscission in C. paliurus . Key message The cell may be subject to physiological stress, promote the accumulation of H 2 O 2 in leaves, and accelerate the degradation of the cell walls of AZ cells and vascular tissues, which results in leaf abscission in C. paliurus.