大气悬浮颗粒物污染对厦门市行道树芒果光合生理指标的影响

随着城市的迅速发展,大气中总悬浮颗粒物(TSP)污染日益严重. 城市植被在吸附和净化TSP的同时,其正常生理生态过程也受到了深刻的影响. 2009年4、5月,对厦门市汀溪清洁对照区、厦大文教区、仙岳商贸区和海沧工业区大气TSP浓度及研究区内行道树芒果(Mangifera indica)的光合生理参数进行监测. 结果表明：汀溪、厦大、仙岳和海沧的日均大气TSP浓度分别为0.061、0.113、0.120和0.205 mg·m^-3;不同功能区行道树芒果受到的胁迫作用为工业区>商贸区>文教区>清洁对照区. 大气TSP污染导致芒果叶片的净光合速率、气孔导度和蒸腾速率显著下降,相关系数均在0.98以上,同时也是胞间CO₂浓度发生变化的重要因素;高浓度的TSP污染通过限制气孔导致芒果的光合强度显著降低.     

Hydraulic and mechanical stem properties affect leaf-stem allometry in mango cultivars

Leaf size-stem size allometric relationships are important features of biomass allocation in plants and are affected by biological functions linking the two organs. They have been studied at specific and supraspecific levels, but not at the infraspecific level. It was hypothesized that allometric relationships link leaf size and stem size at the cultivar level, and are cultivar-specific in relation to distinctive functional stem traits: hydraulic conductivity and mechanical strength. Allometric relationships between leaf size and stem size were established for 3 yr, using the standardized major axis method, on current-year branches, composed of one to 16 growth units, for four mango (Mangifera indica) cultivars characterized by contrasting growth habits. The hydraulic and mechanical stem properties of these cultivars were also measured. The slopes of the relationships were similar among cultivars, but not the y-intercepts. Different y-intercepts in the stem mass vs branch cross-sectional area relationship and in the leaf mass vs stem mass relationship were related to mechanical and to hydraulic stem properties, respectively. These results showed that leaf-stem allometry in mango cultivars was shaped by hydraulic and mechanical stem properties, supporting a functional interpretation of the relationship between leaf and stem dimensions.     

Anti-inflammatory 5-(11'Z-heptadecenyl)- and 5-(8'Z,11'Z-heptadecadienyl)-resorcinols from mango (Mangifera indica L.) peels

Bioassay directed extraction and purification of mango peels revealed the 5-(11'Z-heptadecenyl)-resorcinol (1) and the known 5-(8'Z,11'Z-heptadecadienyl)-resorcinol (2) previously not described in Mangifera indica L. The structures of both compounds were determined by extensive 1D and 2D NMR studies and MS. Both compounds exhibited potent cyclooxygenase (COX)-1 and COX-2 inhibitory activity with IC(50) values ranging from 1.9 (2) to 3.5 microM (1) and from 3.5 (2) to 4.4 (1) microM, respectively, coming close to the IC(50) values of reference drugs. 5-Lipoxygenase (5-LOX) catalyzed leukotriene formation was only slightly inhibited. Structure-activity studies by referring to synthetic saturated homologues indicated that the degree of unsaturation in the alkyl chain plays a key role for COX inhibitory activity, whereas the influence of chain length was less significant.     

Identification of an ETR1-homologue from mango fruit expressing during fruit ripening and wounding

We have isolated a mango (Mangifera indica L.) cDNA homologue of the ethylene receptor gene ETR-1, referred to as METR1, which codes for a polypeptide of 802 amino acids with a predicted molecular weight of 89 kDa. The amino acid sequence is highly homologous (over 80 percnt;) to ETRs from other fruits. Genomic Southern blot analysis indicates that two or more ETR homologues exist in mango. RNA blot analysis revealed that the level of METR1 mRNA in the mesocarp increased during fruit ripening. In addition, it was found that the METR1 mRNA increases transiently during wounding of the tissue. This is the first report of an ETR homologue showing an induction during fruit ripening and wounding.     

Detection of unusual carotenoid esters in fresh mango (Mangifera indica L. cv. 'Kent')

The carotenoid pattern of mango cv. 'Kent' was investigated by LC-(APcI)MS analyses. In solvent extracts from the mesocarp an unusual carotenoid ester was identified as violaxanthin dibutyrate. For unequivocal identification of butyric acid by an independent method, total lipids were isolated by solvent extraction from the fruit flesh and analyzed by GC after saponification and subsequent methylation. Thus, evidence of butyric acid (1.6 area%) was provided. To the best of our knowledge, this is the first report on a xanthophyll dibutyrate in plants. Additionally, further carotenoid peaks were tentatively assigned to 9-cis-violaxanthin and neochrom or luteoxanthin, respectively, by their UV/vis and MS data of the saponified extracts.     

Hybrid status of kuwini,Mangifera odorata Griff. (Anacardiaceae) verified by amplified fragment length polymorphism

Mangifera odorata Griff. (Anacardiaceae), was suggested to be a hybrid between M. indica L. and M. foetida Lour. due to morphological intermediacy. Results from this study show that M. indica and M. foetida produced unique amplified fragment length polymorphism (AFLP) profiles. Mangifera odorata did not produce any unique bands. All the M. odorata samples additively inherit bands specific to M. indica and M. foetida, which strongly suggested the hybrid origin. Three major clusters were produced in the phenogram. All samples of M. indica, M. foetida and M. odorata segregated distinctly. Mangifera odorata was closer to M. foetida than to M. indica, indicating that backcrossing with M. foetida might have taken place. AFLP analysis therefore verified the hybrid status of M. odorata.     

Plant regeneration from protoplasts of mango (Mangifera indica L.) through somatic embryogenesis

 This report describes a protocol for the regeneration of plants from protoplasts isolated from proembryogenic masses (PEMs) in a suspension culture derived from the nucellar callus of mango (Mangifera indica L. cv 'Amrapali'). The maximum yield (24.6±1.1×10⁶), with 81.04±4.1% viable protoplasts per gram PEMs, was obtained with an enzyme mixture containing 1.2% cellulase, 1.0% hemicellulase and 0.6% pectinase. An optimum density of 5×10⁴ cultured protoplasts per milliliter culture medium was required for the highest frequency (88.89±5.40%) of division. Dividing protoplasts developed into microcalli that proliferated on medium supplemented with growth regulators (auxins or kinetin alone, or auxins with kinetin) and produced somatic embryos after transfer to a growth regulator-free medium. The protocallus on 2,4-D-containing medium produced the maximum number (102.50±6.93) of somatic embryos. Maturation of somatic embryos depended upon the presence, and the nature and combination of growth regulators in the medium during proliferation of the callus. The mature somatic embryos germinated and developed into plants that were transferred to soil. Received: 1 April 1999 / Revision received: 27 July 1999 / Accepted: 23 August 1999     

Purification and properties of polyphenoloxidase of mango peel (Mangifera indica)

Polyphenoloxidase from mango(Mangifera indica) peel was purified to homogeneity by ammonium sulphate fractionation, chromatography on DEAE-Sephadex and gel filtration of Sephadex G-200. The enzyme had an apparent molecular weight of 136,000. Its pH and temperature optimum were 5.4 and 50‡C, respectively. The enzyme possessed catecholase activity and was specific too-dihydroxy phenols. The enzyme also exhibited peroxidase activity. Some non-oxidizable phenolic compounds inhibited the enzyme competitively. High inhibitory effects were also shown by some metal chelators and reducing agents, Mango peel polyphenol oxidase when immobilized onto DEAE Sephadex showed slightly higher Km for catechol and lower pH and temperature optima.     

Assessment of potential antagonists for anthracnose (Colletotrichum gloeosporioides) disease of mango (Mangifera indica L.) in North Western Ethiopia (Pawe)

Mango (Mangifera indica L.) is considered as one of the most popular fruits among millions of people in the tropical area and increasingly in the developed countries. Anthracnose, caused by the fungus Colletotrichum gloeosporioides, is the most important pre- and post-harvest disease of mango. The objective of this research was to evaluate the prevalence of different promising antagonistic Trichoderma and Bacillus spp. on phyloplane of mango in Ethiopia and to evaluate their antagonistic potential against the pathogen. A total of 19 mango fields were surveyed and anthracnose affected all fields. Culture studies on potato dextrose agar for evaluation of antibiosis activity of Trichoderma spp. and Bacillus spp. revealed that they have inhibitory and lytic effect on C. gloeosporioides, which is an indication of their potential biocontrol agent for management of mango anthracnose as an alternative to chemical control. Significant differences (p?<?0.05) were observed among Bacillus isolates in causing lysis of pathogen mycelium, when inoculated on actively growing colony of C. gloeosporioides. Maximum reduction in growth rate of pathogen was observed with Bacillus spp. (B50), which restricted the growth to 2.7?mm compared to 8.3?mm in the control with 67.5% efficacies. There were similar effects (p?<?0.05) among Trichoderma spp. in formation of inhibition zones and lysis by varying degrees up to 59.7% efficacies in reducing linear growth of the pathogen in dual culture.     

Mechanisms contributing to the competitive success of the invasive fruit fly Bactrocera invadens over the indigenous mango fruit fly, Ceratitis cosyra: the role of temperature and resource pre-emption

We investigated the influence of temperature and infestation sequence on interspecific competition between two fruit flies: an invasive ( Bactrocera invadens Drew, Tsuruta & White, ( B ) and a native ( Ceratitis cosyra Walker , C ) (both Diptera: Tephritidae) species. Mango fruits [ Mangifera indica L. (Anacardiaceae)] were co-infested with larvae at different constant temperatures (15, 20, 25, and 30 °C) and relative humidity of 50 ± 8%, using different infestation sequences at each temperature ( BC together; BC/CB 1, 2, and 3 days apart). There were significant effects of competition in most experimental treatments, resulting in reduced larval survival, pupal mass, and adult emergence for both species. At most of the infestation/temperature combinations, C. cosyra was clearly the inferior competitor. The only exception was at 20 °C when the outcome depended on the sequence of infestation: no C . cosyra survived when the sequence was BC , but more C . cosyra than B . invadens survived when it was CB . At 15 °C, all C. cosyra larvae died, while the development of B. invadens was prolonged and adult emergence reduced. We conclude that resource pre-emption and fluctuations in temperature in mango agroecosystems help to explain observed shifts in dominance between B. invadens and C. cosyra on mango in many parts of Africa. The small window of competitive superiority for C. cosyra at 20 °C and CB infestation sequence, together with other factors such as fecundity and alternative hosts, may allow for co-existence in some environments.