-Introduction. The Chinese jujube tree always presents some unfavorable performances because its vegetative growth is very vigorous. Our study was conducted to apply root pruning to test whether it can effectively inhibit the vigorous vegetative growth by regulating the competitive ability of the root system for water and nutrients. Materials and methods. For our experiment, roots were cut at three different distances from the trunk (light, moderate and severe root pruning) on both inter-row sides of jujube trees to the depth of 20 cm. Roots of control jujube trees were not pruned. Then we determined for three years the competitive indicators of Chinese jujube trees including the length, number and thickness of primary branches; photosynthetic characteristics and nutrient concentrations of leaves; hormone contents in the jujube head, flower number and fruiting percentage, yield, and fruit quality. Results and discussion. In the early stage after root treatment, root pruning decreased lots of indicators such as concentrations of nitrogen, phosphorus, and potassium in leaves, photosynthesis, transpiration, stomatal conductance, and intercellular CO 2 concentration of leaves, relative to the same indicators as the control group. With the gradual emergence of new roots, these indexes appeared to have adverse patterns with respect to those in the early stage after root pruning. Compared with the control, root pruning significantly decreased the length and number of primary branches and flower number, but thickened primary branches, enhanced fruiting percentage and increased the amount of ethylene release of the jujube head in the whole experiment. Fruit quality was improved with root pruning, as indicated by increases in vitamin C and total sugar and a decrease in titrable acidity. No effects of root pruning were noticed on yield. From our results, we conclude that the removal of the root system at a distance of three times the trunk diameter (severe pruning) from the trunk is the most effective in regulating the competitive ability of the Chinese jujube tree.China / Ziziphus / root pruning / plant response / performance testing / agronomic characters / fruits / quality Effet de la taille des racines sur les performances du jujubier chinois.Résumé -Introduction. Le jujubier chinois présente toujours certaines performances désavantageuses du fait de sa croissance végétative très vigoureuse. Notre étude a été menée pour tester la taille des racines afin de vérifier si elle peut freiner efficacement la croissance végétative en régulant la compétitivité du système racinaire pour l'eau et les nutriments. Matériel et méthodes. Pour notre expérimentation, les racines de jujubiers chinois ont été coupées à trois distances différentes à partir du tronc (taille légère, modérée et sévère des racines), de chaque côté entre les rangs de jujubiers, à 20 cm de profondeur. Les racines des jujubiers témoins n'ont pas été taillées. Nous avons ensuite suivi pendant trois années certains indicateurs de compétitivité du jujubier...

This study aimed to evaluate the effects of Zn on the growth safety and activity of carbonic anhydrase (CA) in foxtail millet (Setaria italica L.). The photosynthetic characteristics, CA activity, and relative gene expression of different varieties of millet at the seedling stage were studied by spraying Zn solution under pot experiment and indoor culture conditions. Results showed that spraying low-concentration Zn solution (20, 40, and 60 mg L −1) reduced malondialdehyde content and intercellular CO2 concentration (Ci) but increased antioxidant enzyme activity, pigment content, and photosynthetic gas-exchange parameters (net photosynthetic rate, stomatal conductance, transpiration rate, except for Ci); meanwhile, spraying high Zn concentration (80 and 100 mg L −1) exerted opposite effects. The optimal growth of millet was achieved when the Zn concentration was 40 mg L −1. At this concentration, CA activity increased and β-CA family expression was upregulated, which exerted little or no effect on other CA families. Compared to Zhangzagu 10 (zinc-resistant variety), Jingu 21 (zinc-sensitive variety) showed a more significant change. This study may serve as a reference for further research on the function of CA and physiological processes, such as photosynthesis in millet, and a theoretical basis for the effective use of Zn fertilizer in millet.