Stomata is the main channel for CO2 to enter into leaf mesophyll cells,and its aperture plays a key role in photosynthetic rate. Previous studies have shown that 5-aminolevulinic acid(ALA)is involved in stomatal regulation in apple leaves,but the underlying mechanism has not been fully elucidated. In the present work,the effects of ALA on cytoplasmic pH and stomatal movement were studied with the abaxial epidermis of leaves of Fuji apple(Malus × domenstica Borkh). Results showed that when stomatal closure was induced by ABA and benzylamine,the fluorescence intensity of cytoplasmic pH and reactive oxygen species(ROS)increased significantly. When ALA and butyrate were used to inhibit ABA-induced stomatal closure,they also inhibited ABA-induced increase of cytoplasmic pH and ROS fluorescence intensity. Benzylamine weakened the effect of ALA on the stomatal closure induced by ABA,while ALA and butyrate inhibited stomatal closure induced by exogenous H2O2 and Ca2+. These results suggest that cytoplasmic pH is involved in stomatal regulation at the upstream of the signal pathway of ALA regulating stomatal movement. Analysis of qRT-PCR showed that ABA induced up-expressions of Mdvha-c2 and Mdvha-c3 which encode subunits of tonoplast H+-ATPase,whereas ALA inhibited this effect. These suggest that cytosolic acidification induced by ALA may be related to the decrease of ion pump activity in the vacuolar membrane. Based on the above results,the authors conclude that the effect of ALA on stomatal movement in apple leaves is mediated by cytoplasmic pH pathway.
In this study,the volatile components in every whorl of the tepal of Magnolia denudata ‘Feihuang’flower at bud stage,semi-open stage and fully-open stage were identified using Headspace–Gas Chromatography–Mass spectrometry(HS–GC–MS)and confirmed with NIST11 database and retention index(RI). The quantitative data were obtained by internal standard and the odor-activity values(OAVs)were evaluated by referring the thresholds. Total of 74 volatiles were identified in tepals during its development. Among 39 volatiles,52.70% of the total,were present in each whorl,others were present varied with the whorls. The results showed terpenoids were the main volatile components existed in M. denudate‘Feihuang’flower,reached 54 kinds(72.98 % of the total),β-pinene,β-myrcene,eucalyptol,sabinene,α-pinene,terpinolene,d-limonene,cis-β-ocimene,γ-terpinene were the major volatiles(content over 1.0 μg ? kg-1). The most 61 volatiles were detected in middle whorl,and the highest 148.40 μg ? kg-1 was found in inner wheel at semi-open stage. The volatiles were mainly formed at the bud stage,then several new substances were found at semi-open stage,however,just one generated at follow stage. The whole tepal,from the bud stage to semi-open stage,the volatiles generated was greater than released,leading to accumulation during the development,but from semi-open stage to fully-open stage,on the contrary,the content obviously decreased,which raised highest amount and strongest aroma intensity presented at semi-open stage. Herbal,green and woody were the main aroma characteristics,and 9 higher content terpenoids possessed of obvious aromatic effect showed by aroma quality and strength.
In this study,carbon utilization of Ganoderma lucidum was analyzed following CO2 emission and lignocellulose degradation during colonization of substrate and during fruiting body formation. The results show that during growth of G. lucidum the utilization rate of carbon was 48.3% of which 12.5% of carbon was converted into the fruiting body and 35.8% of the carbon was emitted in the form of CO2. CO2 emission peaked at three times,respectively when the mycelium finished colonizing the substrate,during primordium formation,and during fruiting body maturation. Cellulose and hemicellulose were mainly degraded during colonization of the substrate by the mycelium up to primordium formation,while lignin was mainly degraded during the growing period of the fruiting body.