Cytological studies on the incompatibility of protoplast fusion in crops

1. 对绿豆叶肉原生质体和红豆细胞悬浮液原生质体进行了电融合和电镜观察。在融合产物中，绿豆叶绿体和红豆原质体分别在其原侧进行分组。在一些子细胞中观察到叶绿体的消除。研究了碘乙酰胺（IOA）对红豆原生质体的影响。IOA诱导粗内质网过度形成，随后细胞质塌陷。然而，如果将ioa处理的原生质体与未处理的绿豆原生质体融合，则超微结构损伤会减轻。将烟草叶肉原生质体和大豆细胞悬浮液原生质体在不同的培养基中进行融合培养，对亲本原生质体的分裂活性有不同的影响。在有利于大豆原生质体分裂的培养基中，烟草叶绿体从子细胞中去除的最多，而在有利于烟草原生质体分裂的培养基中则没有。通过C_3种鸡冠花（Celosia cristata）与C_4种苋菜（Amaranthus tricolor）原生质体融合获得了属间体细胞杂交愈伤组织。酸性磷酸酶同工酶分析证实了愈伤组织的杂交性。因此，在原生质体融合的早期过程中，即使是在远缘种之间，也没有观察到不相容反应。细胞器的消失似乎是由于细胞分裂过程中细胞器的不均匀分离而逐渐发生的。

1. Mesophyll protoplasts of mung bean and cell suspension-derived protoplasts of azuki bean were electrofused and examined by electron microscopy. Chloroplasts from mung bean and proplastids from azuki bean were grouped respectively and located on their original sides in fusion products. Elimination of chloroplasts was observed in some daughter cells.2. Effects of iodoacetamide (IOA) on azuki bean protoplasts were examined. IOA induced an overformation of rough endoplasmic reticulum which was followed by the collapse of cytoplasm. However, ultrastructural damages were mitigated if the IOA-treated protoplasts were fused with untreated mung bean protoplasts.3. Tobacco mesophyll protoplasts and soybean cell suspension-derived protoplasts were fused and cultured in various media in which division activity of parental protoplasts was differently affected. Elimination of tobacco chloroplasts from daughter cells was the highest in the medium profitable to division of soybean protoplasts but was not observed in the medium profitable to tobacco protoplasts.4. Intergeneric somatic hybrid calli were obtained through protoplast fusion between Celosia cristata (C_3 species) and Amaranthus tricolor (C_4 species). Isozyme analysis of acid phosphatase confirmed the hybridity of calli.In conclusion, incompatibility reaction was not observed in early processes of protoplast fusion even between remote species. Elimination of organelles seems to occur gradually due to unequal segregation of organelles during cell divisions.