Analysis On Cold Resistance Of Almond Buds And Observation Of The Dehiscence Process Of Almond Anthers

In this experiment, Yingzui, Zhipi, Nonpareil, Mission and wild almond were chosen as research materials to measure the contents of soluble sugar, starch, MDA, proline and soluble protein and changes of the relative conductivity with the methods of isolated branches hydroponics and natural frost simulation to compare their cold resistance as well as explore their cold resistance mechanism with the subordinative function method, hoping to provide references for the cultivation and breeding; In order to create theoretical basis for the cultivation and production of almond, the pollen quantities and pollen germination rate were also determined in this experiment to analyze the effects of different low temperatures on the germination rate of almond pollen; Moreover, with the purpose of analyzing comprehensively the biological principles of almond anther dehiscence and offering help for the artificial control of anther dehiscence and the achievement of efficient production, Yingzui almond anthers at different developmental stages were considered to be research objects, and their internal structures were dyed by using paraffin method together with iron hematoxylin staining, coomassie brilliant blue staining and PAS staining, meanwhile the internal structures were observed in pictures taken with Nikon i80 high power microscope and the dehiscence process were photographed with SMZ–250 stereo microscope. The main conclusions attained from this experiment were as follows:1. Within 24 hours and under –4 ℃ treatment, changes of 6 indexes in Yingzui almond buds and wild almond buds in the big bud periods were: Contents of soluble sugar and MDA changed from rising to falling then to rising; Contents of soluble protein decreased at first, then increased; Contents of starch experienced a change from rapid decreasing to slow increasing; Contents of proline in “Yingzui” almond buds changed from increasing to decreasing while that of wild almond buds changed from increasing to decreasing then to increasing; Curves of the relative conductivity took the shape of “S” for continuous increasing. The average subordinative function degrees of the six indexes in two kinds of almond buds rose at first but later fell. Cold resistance mechanisms of the almond buds worked quickly, and their cold resistance capabilities changed from increasing to decreasing.2. The cold resistance degrees of the buds in four cultivated almonds and wild almond displayed as: Yingzui > wild almond > Nonpareil > Mission > Zhipi.3. Yingzui almond buds were processed under different temperatures. The result showed that both the content of soluble sugar and the content of total sugar experienced the high–low–high change, the content of starch decreased first and then increased, and the ratio of soluble sugar content and total sugar content changed from an increasing state to a decreasing state with the reducing of treatment temperature and the lengthening of treatment time.The anthers, petals and sepals had obvious reactions to cold stress under the treatment of –2 ℃ for 24 h, the treatment of –4 ℃ for 18 h, and the treatment of –6 ℃ for 12 h, while the scales only had an apparent reaction to cold stress under the treatment of –4 ℃ for 18 h and the treatment of –6 ℃ for 12 h.4. For the four cultivated almonds and wild almond, the average anther number of one single flower displayed as: Nonpareil > Mission > Zhipi > Yingzui > wild almond, both the average pollen amount of one single anther and the average pollen amount of one single flower presented as: Zhipi > Yingzui > Nonpareil > Mission > wild almond, and the pollen germination rate demonstrated as: Zhipi > Nonpareil > Mission > Yingzui > wild almond, meanwhile the frost could significantly reduce the pollen germination rate during the flowering period.5. The changes of cell structures of Yingzui anthers before and after the anther dehiscence included the programmed death of middle layer cells, tapetum cells and stomium organizations, the rapid growth of pollen grain volume, the irregular changes of epidermal cells and endothecium cells, the formation of the second–thickening spiral fiber and the Polysaccharide decomposition of endothecium cells.