摘要
以大叶杨为母本,分别与小叶杨、欧洲黑杨、响叶杨进行人工杂交,并以大叶杨×大叶杨为对照,观察其花粉与柱头相互作用的超微结构变化。结果表明,大叶杨柱头细胞在授粉前表现生理活跃,含丰富的细胞器,壁外被含分支通道的角质层。接受大叶杨及欧洲黑杨花粉的柱头细胞内部仍有丰富的细胞器,膜结构保存完好。接受小叶杨及响叶杨花粉的柱头细胞衰亡较快,授粉部位沉积厚的胼胝质,细胞内部液泡化,膜结构逐渐消失,细胞质电子密度加大。欧洲黑杨花粉行为与大叶杨花粉行为相似,花粉能迅速萌发,并以短管形式穿入柱头,异常行为罕见。小叶杨及响叶杨花粉萌发后只有半数花粉管能以短管形式进入柱头,其中部分管内沉积胼胝质,另半数花粉管在柱头上表现各种异常行为——扭曲、爬行、肿胀、提前破裂释放内容物及先端沉积胼胝质。由各种花粉在大叶杨柱头上的行为和大叶杨柱头对各种授粉的反应判断,与大叶杨杂交亲和力在柱头阶段表现由强至弱依次是欧洲黑杨、小叶杨、响叶杨。
The ultrastructural changes of pollen-stigma interaction were studied under artificial pol- lination in intersectional crosses of Populus lasiocarpa Oliv.X P.nigra L.,P.lasiocarpa Oilv. X P.simonii Carr.,P.lasiocarpa Oliv.X P.adenopoda Maxim.and P.lasiocarpa Oliv.X P. lasiocarpa Oliv..The results are as follows. Before pollination,the stigmatic ceils of P.lasiocarpa containing large amounts of endo- plasmic reticulum,abund ant dictyosomes and well-developed mitochondria appear physiologi- cally active.Its outer walls are covered by a layer of cuticle with numerous branching channels toward the outer space. When the pollens of P.lasiocarpa and P.nigra are dusted,respectively,to the stigma of P.lasiocarpa,the degeneration of the stigmatic cells are rather slow.The cuticle of the stig- ma surface just adjacent to the alighting pollen is dissolved,but the cell contents still have large amounts of endoplasmic reticulum and the structure of the membrane system remains dis- tinctly. When the pollens of P.simonii and P.adenopoda are forced,respectively,upon the stigma of P.lasiocarpa,the stigmatic cells degenerate rapidly.In addition to the disruption of the cuticle,heavy callose is deposited on the walls of the stigma cells adjoining the dropping pol- lens.Numerous vesicles are formed by the rough endoplasmic reticulum,and the electron den- sity is increasing.The structure of the membrane system disappears gradually and becomes indistinct.Osmiophilic globuli occurs in the central vacuole.Plastids accumulate starch gra- ins. The behavior of pollen tubes of P.nigra is similar to that of P.lasiocarpa.The pollen grains germinate rapidly and the pollen tubes penetrate into the stigma after the short-tube pat- ten.Abnormal behavior is rare.A lot of minute exudates appear on the pollen walls. As for P.lasiocarpa X P.simonii and P.lasiocarpa X P.adenopoda,only half of the tu- bes can penetrate into the stigma after short-tube patten and is associated with callose deposi- tion on the walls.The other half arresting on the stigma surface shortly after germination shows abnormal behavior;such as swelling,creeping,bursting,twisting and distortion with callose deposition on the tip of the pollen tubes. As a result of our experiments,It is concluded that the degeneration speed of the stigma- tic cells may be a sign of incompatibility and the crossability in progamic phase may arrange as follows:P.lasiocarpa X P.nigra,P.lasiocarpa X P.simonii,P.lasiocarpa X P.adenopoda. The first one is compatible while the second and the third are incompatible.
基金
中国科学院科学基金资助的课题
