pH影响Ca^(2+)和EGTA对水霉(Saprolegnia ferax)菌丝顶端生长的作用效应  

EFFECTS OF pH ON THE ACTION OF Ca^(2+) AND EGTA ON HYPHAL TIP GROWTH OF SAPROLEGNIA FERAX

作　　者：袁生[1] 窦洁[1] 陆玲[1] 薛绍白[2] 

机构地区：[1]南京师范大学生物系,南京210097 [2]北京师范大学生物系,北京100875

出　　处：《实验生物学报》1998年第1期13-20,共8页Acta Biologiae Experimentalis Sinica

基　　金：国家自然科学基金[No.39670375];国家教委优秀年轻教师基金[No.1993(436)]~~

摘　　要：水霉(Saprolegia ferax)菌丝在pH6.0-8.0的OM液体培养基中生长良好,在pH5.0时生长速率有所下降,在pH3.0—4.0时停止生长。短时间(30min)作用研究表明,低浓度的CaCl_2促进pH5.0(1—5mmol/L)和pH6.0(1mmol/L)条件下的菌丝顶端生长,抑制pH7.0—8.0条件下的菌丝生长。1mmol/L以上的EGTA则抑制pH5.0条件下菌丝顶端生长,促进pH6.0—8.0条件下的菌丝顶端生长。但CaCl_2和EGTA都不能使pH3.0—4.0条件下的菌丝恢复生长。长时间(8h)作用跟踪观察表明,2mmol/L EGTA(pH6.8)短时间作用可促进菌丝生长,但随着培养时间延长,则产生抑制作用,并诱导原生质从菌丝最顶端喷出。说明细胞壁Ca^(2+)起着提供胞外Ca^(2+)源和细胞壁修饰成分的双重作用。Ca^(2+)通道阻断剂verapamil对菌丝顶端生长的抑制作用也说明顶端生长所需的Ca^(2+)来自胞外。The tip growth of hyphae was good in OM liquid medium (pH6. 0-8. 0),whereas reduced in the medium (pH5. 0)and completely ceased in the medium (pH3. 0-4. 0). For a shorter time of treatment (30min) ,low concentration CaCl2 stimulated tip growth of hyphae under pH 5. 0 condition (1 -5mmol/L CaCl2)or pH6. 0(1 mmol/L CaCl2), but inhibited the tip growth of hyphae under pH 7. 0-8. 0 conditions. 1 -20mmol/L EGTA inhibited tip growth of hyphae under pH5. 0 condition, whereas stimulated tip growth of hyphae under pH6. 0 - 8. 0 conditions. However, EGTA and CaCl2 could not resume growth of hyphae under pH 3. 0-4. 0 conditions. For a long time of treatment (8h),though the tip growth rate of hyphae grown in the medium(pH6. 8)containing 2 mmol/L EGTA was greater during first 30min, it gradualy decreased with prolongation of time and finally down to zero after about 8h,and meanwhile protoplasm usually bursted out from the tip of hyphae. Above results suggested that Ca2+ in cell wall may play dual roles as a extracellular Ca2+ resouces and a modification proportion of cell wall. Ca2+ channel blocker verapamil could inhibit tip growth of hyphae, which also impplied that Ca2+ needed for tip growth came from the outside of hyphae cell.

关 键 词：水霉 菌丝顶端 生长 钙pH EGTA 

分 类 号：Q949.323.2[生物学—植物学] Q945.3