Studies On Pollination Biological Character Of Pistachio

In this research, ten introducted varieties of Pistachio (Pistacia Vera L.) in Taihang mountain have been studied systematically on the variation discipline of growth, morphological and biochemical character from phenology, morphologic, anatomy, and so on. They are flower bud differentiation, phenological phases to blossoming, character of blossoming, germination and storage of pollen, effects of plant growth regulating substances on pollen viability, pollen morphology, the growth and development of fruits. Comprehensive analysis has been made for these indexes in order to reveal the internal mechanisms and to provide scientific basis for research of Pistachio pollination biology.. The results as follow:(1)The differentiation process of flower bud of Pistachio began to grow at the end of March and ceased in the mid of May. According to the sequence of the formation of flower bud, it was divided into five periods. Those wereâ‘ no flower bud differentiation stage;â‘¡inflorescence primordium differentiation stageâ‘¢lateral flower primordium differentiation stageâ‘£lateral inflorescence primordium differentiation stage⑤the end stage of flower bud differentiation. It was discovered that the sequence of flower bud differentiation expended from the basal to the top,and from the edge to the center. The end stage of flower bud differentiation was relatively long and slow, and all the lateral flowers finished differentiation almost at the same time.(2)The discipline of inflorescences growth varied differently in the varieties of Pistachio, the flower bud of the male growed earlier than that of the female, and the former's growth began in the late ten days of March, while the later's growth began at the end of March. The inflorescences growth of 'B'and Peter started earlier than that of T11, and the inflorescences growth of the former two began on about March 20, while the later on about March 27, and the time of the inflorescences growth of each variety lasted 15～20d. The inflorescences growth of the seven female varieties was consistent and all began on about April 10, while the flowering phenologies of the three male trees was different obviously, male trees of 'B' and Peter beginning their flowering earlier 10d than T11's which started on about April 10.(3)In two cultivars ofPistacia vera L, B and Peter, temperature and culture media with different concentrations of sucrose and boric acid were studied in order to select one best for in vitro pollen germination and tube growth. Besides, the effects of different storage conditions were also tested. The results indicated that the optimum culture medium for pollen germination of two cultivars and tube growth of B was the one composed of 15% sucrose, 100 mg·L^-1 boric acid at 25℃, which was the optimum temperature for pollen germination and growth. The most suitable culture medium and temperature for pollen tube growth of Peter was the same as the former except the optimum boric acid concentration, which was 200mg·L^-1. Storage conditions had great effect on pollen viability, and the vitality of the two species of Pistachio pollen declined with increase of number of store days in different storage conditions. The suitable temperature for keeping pollen viability was -18℃, followed by 4℃and 18℃room temperature.(4)The effects of several plant growth regulating substances on in vitro pollen germination and tube growth of pistachio were as follows: the rate of pollen germination and tube growth of pistachio were enhanced by the lower concentration of GA₃, IAA and 2, 4-D and were inhibited by the higher concentration of them. The optimum concentration of GA₃, IAA and 2, 4-D which stimulated pollen germination and pollen tube growth were 5～25mg·L^-1, 5～15mg·L^-1 and5～15mg·L^-1 respectively,α-NAA could lightly increase pollen germination by the lower concentration, and highly inhibited by the higher concentration. Plant growth regulating substances should be used choicely in product.(5)The pollen morphology of 3 types of Pistachio were studied by optical microscope and scanning electron microscope. It showed that a majority of the pollen grains, was long-globous existing with monads, The shape of T11's eolporate was long culpus while the others' was round aperture, The exine ornamentation of pollen grains of T11 and 'B' were foveolae reticulate sculpture, but the exterior of the former had a lot of white grains while that's of the later had a few white grains. Peter's exine ornamentation was reticulate sculpture with a lot of white grains.The order of pollen size was Peter＞B＞T11.(6) The experiment of pollination showed that T471 (♀) had high compatility of the pollen of 'B' (♂), and T471 (♀)×'B'(♂) was the best combination, whose fruit set rate was 18.5%. The quality and the quantity of 'B' pollen were better than those of Peter pollen, and can satisfy with the need of female trees in flowering stage.The growth and development of the fruit in Pistachio was about double S-shaped curves, the whole course was divided into four periods: the first fast growth period of fruit was from April 16 to May 26, and during this period the pericarp growed speedily and the vertical diameter, horizontal diameter increased fast and they reached the final size basically; The second period was the stage of the pericarp's lignification (May 27～End of June), and in the stage there was no change in the fruit except the pericarp lignifies, moreover, the embryo doesn't development and the fruit was empty; Next period was the sencond fast growth period of fruit, and this period was from the beginning of July to August 24 during which the embryo growed fast and forms the seed; The last period was the time of fruit ripeness, and during this period (from the end of August to the beginning of September) the size and the fresh weight of the fruit arrived at a stale state.