濒危植物矮沙冬青减数分裂期染色体行为的观察

用涂片法和酶解法，观察了濒危植物矮沙冬青的减数分裂过程。在减数分裂双线期末或终变期初，可以观察到9个二价体，在中期Ⅰ末至后期Ⅰ初，同源染色体基本排列在赤道板上，然后在纺锤丝的牵引下二价体的两条同源染色体分开，分别移向两极，每一极有9条染色体，从而确认该属植物的染色体基数为x=9。在矮沙冬青减数分裂过程中，没有发现染色体有异常行为，认为其小孢子形成过程正常。因此认为矮沙冬青濒危不是染色体行为异常和小孢子发育不正常而造成的。

Observation on the Chromosome Behavior at Meiosis of Ammopiptanthus nanus

The meiosis of Ammopiptanthus nanus,an endangered species of Leguminosae,was observed under Olympus Vanox microscope.The materials collected from Wuqia County in Uygur Autonomous Region of Xinjiang were fixed in Carnot's fluid,then washed in absolute ethanol and preserved in75%ethanol.Slide specimens were prepared by smear method and enzyme-disaggregated method.There are nine bivalents in pollen mother cells at late diplotene or early diakinesis,and the homologous chromosomes essentially arrange on the equatorial plate at late metaphase I or early anaphase I,then the two homologous chromosomes of each bivalent separate from each other and move to two opposite poles drawn by spindle fibers.Nine chromosomes at each pole are observed,therefore the basic chromosome number of this species should be x=9.In addition,abnormal behavior of chromosome is not found in the process of meiosis,so the development of microspores is regarded as normal.It is suggested that the endangerment of the species is not related to the chromosome behavior.