RESUMEN
OBJECTIVE: Chilling tolerance of salicylic acid (SA) in banana seedlings (Musa acuminata cv., Williams 8818) was investigated by changes in ultrastructure in this study. METHODS: Light and electron microscope observation. RESULTS: Pretreatment with 0.5 mmol/L SA under normal growth conditions (30/22 degrees C) by foliar spray and root irrigation resulted in many changes in ultrastructure of banana cells, such as cells separation from palisade parenchymas, the appearance of crevices in cell walls, the swelling of grana and stromal thylakoids, and a reduction in the number of starch granules. These results implied that SA treatment at 30/22 degrees C could be a type of stress. During 3 d of exposure to 7 degrees C chilling stress under low light, however, cell ultrastructure of SA-pretreated banana seedlings showed less deterioration than those of control seedlings (distilled water-pretreated). CONCLUSION: SA could provide some protection for cell structure of chilling-stressed banana seedling.
Asunto(s)
Musa/ultraestructura , Ácido Salicílico , Adaptación Fisiológica , Frío , Microscopía Electrónica , Musa/fisiología , Hojas de la Planta/ultraestructura , Transpiración de PlantasRESUMEN
The mRNA differential display method was applied to identify banana genes that were regulated by salicylic acid (SA) during chilling stress. Eighteen cDNA fragments induced by SA during chilling stress were retracted. Seven of them were affirmed by reverse Northern hybridization to be significantly induced. Two most differential fragments (G and A) of them were cloned and sequenced. Nucleotide sequence analysis showed that clone G fragment had 92% homology to partial cDNA sequences of two cold-related genes in soybean (Glycine max) and clone A did not show any identity to previously reported sequences in GenBank database.
Asunto(s)
Perfilación de la Expresión Génica , Musa/genética , Ácido Salicílico/farmacología , Plantones/genética , Secuencia de Bases , Northern Blotting , Frío , ADN Complementario/química , Datos de Secuencia MolecularRESUMEN
The paper is concerned about a teaching and learning reform of hybridization experiment of Drosophila melanogaster. In the teaching of genetic experiment, we have adopted a new teaching and learning method which was a discovering way instead of traditional method. In this way, students themselves selected the combination subject, put forward and carried out the whole experiment scheme. By the reform,we could find out that it was helpful not only to improve students' thinking and operating abilities but also to encourage their interests in genetics.