Lansac A R, Sullivan C Y, Johnson B E, Lee K W
Agronomy Department, US Department of Agriculture, University of Nebraska, Lincoln, NE 68583, USA.
Ann Bot. 1994 Jul;74(1):27-33. doi: 10.1093/aob/74.1.27.
Previous studies have demonstrated that pollen of sorghum [Sorghum bicolor (L.) Moench] loses capacity to both germinate in vitro and to set seed in vivo soon after being shed. The current study evaluates the capacity for dehydrated pollen to effect in vitro germination, reduce tetrazolium chloride, and set seed on cytoplasmic male sterile plants. Morphological changes during pollen germination were examined by scanning electron microscopy (SEM). Close to 70 % of the pollen germinated in 5 min, or less, when collected at 80 % relative humidity (RH) and stored in sealed glass vials. Pollen tubes elongated autotropically with atmospheric humidity apparently being a controlling factor in the process. Pollen dehydrated at 50% RH and 25 degrees C for 15-30 min neither germinated in vitro, reduced tetrazolium chloride, nor set seed on male sterile plants. Rehydrating the pollen did not restore the capacity for germination. SEM micrographs demonstrated that elongating pollen tubes encircled the pollen grain and were contiguous to the surface. A fibrillar-like material existed on the exine of separated pollen grains at the point where the grains had been previously attached.
先前的研究表明，高粱[Sorghum bicolor (L.) Moench]花粉在散落之后很快就会丧失体外萌发能力和体内结实能力。本研究评估了脱水花粉进行体外萌发、使氯化三苯基四氮唑还原以及在细胞质雄性不育植株上结实的能力。通过扫描电子显微镜（SEM）检查了花粉萌发过程中的形态变化。当在相对湿度（RH）80%的条件下收集并储存在密封玻璃瓶中时，近70%的花粉在5分钟或更短时间内萌发。花粉管自主伸长，大气湿度显然是该过程中的一个控制因素。在50%RH和25℃条件下脱水15 - 30分钟的花粉既不能在体外萌发，也不能使氯化三苯基四氮唑还原，且不能在雄性不育植株上结实。对花粉进行复水并不能恢复其萌发能力。扫描电子显微镜照片显示，伸长的花粉管环绕着花粉粒并与花粉粒表面相连。在分离的花粉粒外壁上，先前花粉粒附着的部位存在一种纤维状物质。
