功能矫形前伸青春期大鼠下颌后浅层嚼肌细胞凋亡的研究

目的：研究功能矫形前伸大鼠下颌后浅层嚼肌细胞凋亡的变化规律,探讨功能矫形的肌肉改建机理。方法：选用50只5周龄Sprague-Dawley（SD）雄性大白鼠,随机分为实验组和对照组各25只。实验组大鼠戴自制上颌功能矫治嚣,引导下颌前伸,并打开咬合。利用RT-PCR方法检测两组大鼠浅层嚼肌Bcl-2和Bax基因表达情况,利用TUNEL方法检测浅层嚼肌细胞凋亡情况。结果：①Bcl-2和Bax基因表达随大鼠戴用矫治器时间的延长而升高,至第3周开始下降但仍高于对照组,但Bax的表达高于Bcl-2。Bax/Bcl-2比值随大鼠戴用矫治器时间的延长而升高,至第4周开始下降。②TUNEL实验结果显示浅层嚼肌细胞在戴用矫治器1天后,开始出现凋亡,随着时间延长而增加,至第3周达到顶峰,第4周开始下降。结论：①Bax/Bcl-2比值升高促进浅层嚼肌细胞凋亡。②功能矫形可引起浅层嚼肌细胞凋亡,导致肌肉的结构和功能发生适应性改建。     

天童常绿阔叶树种栲树生殖个体大小及其生殖构件特征

对浙江天童木荷-栲树林内的常绿阔叶树种栲树(Castanopsis fargesii Franch.)的生殖个体大小、生殖构件的分布及其动态变化特征进行了研究。结果表明, 该地区栲树生殖个体的胸径在17~50 cm 间, 平均胸径为31. 2±8.0 cm, 平均年龄约36.3±6.6 年;林缘附近的生殖个体小于木荷-林内。相对稳定的群落和比较丰富的土壤养分条件有利于生殖枝数量和花序数量的增多。栲树生殖个体的数量在两年中变化较大, 部分栲树个体可以在连续年份中生殖。从枝系水平分析:在持续生殖的栲树个体上, 生殖枝数量有明显变化, 并非所有的生殖枝在两年中都可开花或结果, 保持连续生殖的枝系约占48.2%。栲树果序枝数量在连续年份有明显差异(p < 0.01), 而且果序枝上的幼蕾数、果实数量及结实率等都有明显差异(p < 0.05)。     

Secondary galling: a novel feeding strategy among ‘non‐pollinating’ fig wasps from Ficus curtipes

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