Studies On The Morphological Anatomy And The Seasonal Changes Of The Leaves Of Four Species Of Kobresia In Alpine Grassland

In virtue of light microscope, scanning electron microscope and transmission electron microscope, this paper made a study on the morphological anatomy of the leaves of 4 species of Kobresia that were in different growing period in the Alpine grassland of Jin Qiang river area of Eastern Qilian mountains on the level of microstructure and ultrastructure. Four species of Kobresia were as follows, K. royleana, K. humilis, K. pygmaea and K.capillifolia. The results indicated:1. The thickness of the leaves of 4 species was enhanced gradually from initial green up period to exuberance period. Compared with each other, the thickness of mature leaves of the 4 species was as follows, K.capillifolia (360.5μm)>K. pygmaea(290.2μm)>K. royleana(248.9μm)>K. humilis(207.2μm).2. There were relatively thicker cuticular membranes on the upper and the lower epidermises. The thickness of the upper cuticular membrane and the lower one became accretion gradually from initial green up period to the middle period of exuberance or late period of exuberance. The thickness of the upper cuticular membrane was bigger than the lower one in K. royleana, K. humilis and K. pygmaea, while it was on the contrary to K.capillifolia.There were prickle-hairs at both leaf margine of 4 species, with short barbs in K.capillifolia.3. There were bulliform cells in adaxial groove of main vein, the number of them was 10 in K. royleana, 8-9 in K. humilis, while there was none to K. pygmaea and K.capillifolia.4. The stomatal apparatus of 4 species of Kobresia were only distributed on the lower epidermis. The type of the stomatal apparatus was paracytic. The stomatal density of the stoma band in the mature leaves was just as follows, K. royleana(650.0/mm~2)>K. humilis(330.0/mm~2)>K. pygmaea(155.3/mm~2)>K.capillifolia (148.6/mm~2).5. There were no differentiations between palisade tissue and sponge tissue in mesophyll. The palisade tissues were developed. In the mature leaves, the palisade tissues were distributed on both sides of upper and lower epidermis of K. royleana and K. humilis. There were 4-7 layers of palisade tissues and the thickness of them was 102.9μm, while it were 4-6 layers and 91.5μm thick in K. humilis. The palisade...