Basipetal Gradient of Axillary Bud Inhibition Along a Rose (Rosa hybridaL.) Stem: Growth Potential of Primary Buds and their Two Most Basal Secondary Buds as Affected by Position and Age

InRosa hybridaL. cv. Ruidriko ‘Vivaldi’®, theeffect of position on growth and development potentials of axillarybuds was investigated by single internode cuttings excised alongthe floral stem and its bearing shoot. The experiments werecarried out in both glasshouses and in a phytotron. The studyfirstly concerned the development of the primary shoot fromthe onset of bud growth until anthesis. The primary shoot wasthen bent horizontally to promote the growth of the two mostproximal secondary buds, the collateral buds, already differentiatedinside the primary bud. They gave rise to basal shoots. In thebasipetal direction, the axillary buds along the floral stemexhibited both an increase in the lag time before bud growthand a decrease in bud growth percentage, demonstrating the existenceof a physiological basipetal gradient of inhibition intrinsicto the buds or due to short range correlations. The same basipetalgradient of inhibition was observed along the floral stem andits bearing shoot, demonstrating that the age of the bud wasnot a major factor in determining the rate of bud growth. Afterbending the primary shoot, the percentage of collateral budgrowth was also affected by the cutting position. The more proximalthe cutting, the lower the sprouting ability of collateral buds.The growth potential of these buds appeared to be already determinedinside the main bud before cutting excision.Copyright 1998 Annalsof Botany Company Axillary bud; basal shoot; cutting; development; endodormancy; growth; paradormancy; position; primary shoot;Rosa hybridaL.; rose; secondary bud; topophysis.     

探究式课程设计在医学生临床决策能力培养中的探索

临床决策能力是一个医生的必备能力之一，是医学教育中必要且重要的培养目标之一。目前对医学生临床决策能力的培养没有形成完备的体系，一般安排在高年级阶段进行，为时较晚。如何把临床决策能力的培养融入低年级基础课中，以尽早开展能力训练值得探索研究。本研究以医学遗传学课程为例，结合探究式教学方式的特点，模拟临床决策思维过程的各细分模块，优化了课程设计，探索在低年级课程中融入临床决策能力的培养。结果提示：探究式课程设计能充分调动学生主动性，增加学生分析、思考的投入；在教师引导下，促使学生依循临床决策思维的过程得到有效地训练。最后，整理分析了探究式课程设计及实践的思路，总结了设计原则和要点，反思了教学中的经验得失。