草芍药,野牡丹和黄牡丹的核型研究

本文报道了国产芍药属(Paeonia L.)植物草芍药、野牡丹和黄牡丹的染色体数目及核型,均为2n=10=6m 2sm 2st,它们分别具2、3和4对次缢痕,所具次缢痕的数目和位置可以作三种核型的区别特征。     

SOMATIC EMBRYOGENESIS AND PLANT REGENERATION FROM TISSUE CULTURES OF PENNISETUM AMERICANUM,AND P. AMERICANUM x P. PURPUREUM HYBRID

Immature embryos as well as explants obtained from young inflorescences of Pennisetum americanum (pearl millet) give rise to callus tissues on nutrient media containing 2,4-dichlorophenoxyacetic acid (2,4-D). A compact and pale-yellow callus that arises from the peripheral cells of the scutellum, and from the young inflorescences, undergoes further organized growth. When transferred to a 2,4-D-free medium, supplemented with indole-acetic acid or kinetin, or both, embryoids are formed in the organized areas of the callus. Embryoids show a bipolar organization with a shoot-coleorhiza (root) axis and have a coleoptile-like structure surrounded at the base by a cup-shaped structure that resembles the scutellum in texture and morphology. Embryoids show bilateral or radial symmetry and “germinate” in vitro to form plants that have been grown to maturity in soil. Similar embryogenic callus cultures have been produced from young inflorescence tissues of hybrid Pennisetum, a triploid sexually sterile hybrid of P. americanum x P. purpureum. Plants derived from these have also been transferred to soil. The regenerated plants showed normal chromosome numbers.     

4. WATERFOWL AND WADERS AT FORT BEAUFORT,C.P.

TREE, A. J. 1979. Biology of the Greenshank in southern Africa. Ostrich 50:240-251.

The Greenshank Tringa nebularia is a widespread visitor to southern Africa but is only normally common at favoured coastal sites. First migrants arrive at the end of July and the last birds leave in early May. Small numbers overwinter. Birds in the interior are forced to move coastward or southwestward once the summer rains set in and rapidly inundate suitable habitat. Peak numbers occur in January at Port Alfred, a coastal site. Greatest concentrations of Greenshanks occur on eutrophic bodies of water in the interior while at coastal localities the density of prawns appears to determine Greenshank numbers. It is normally a diurnal feeder but will feed at night in tidal areas when fattening up for return migration. It roosts communally standing in shallow water. Birds can be aged on plumage condition and primary feather moult. Birds have a lean mass of about 170 g while the potential migratory range on fat deposits accumulated is calculated to carry birds from the Cape coast to the East African lakes and thence to the Mediterranean or Caspian Seas. There is a considerable disparity in mass between inland and coastal localities. One banding recovery in Cyprus is noted; a low retrap rate is gradually being improved by colour ringing.     

富钟瘰螈与广西瘰螈消化系统和呼吸系统的比较解剖

富钟瘰螈的舌和齿比广西瘰螈的略发达,雄性消化道远长于雌性的,个体的两肺长度差异也较后者大。