Study On The Main Biological Characteristics Of Bromus Ircutensis

This research, based on three perennial forages Bromus ciliatus, Bromus inermis and Bromus ircutensis,Photosynihetic rate, stomatal conductance,intercellular carbon dioxide concentration and water use efficiency indicato by L1-6400 photosynthesis system., their phenological,tillering characteristics and stem/leaf ratio were also observed, mastering the law of growth dynamic change and providing a theoretical basis of seed production to the improving hybrid of Bromus forages by observing phenological period and testing agronomic traits and production performance.The results of the research are as follows:1. The each phenological period of Bromus ciliatus and Bromus inermis is earlier than that of Bromus ircutensis; 3 species of perennial forages change more slowly before jointing stage at the area of tiller number, while they change faster later; the capacity of tillering of Bromus inermis Leyss was the best(65), while that of Bromus ircutensis Kom(6) was the worst;the stem/leaf ratio of the Bromus ciliatus is biggest in heading stage, while the stem/leaf ratio of Bromus ircutensis is smallest.2.The diagram of photosynthesis day dynamic which is based on 3 kinds of perennial forages in jointing stage show the shape of double peak, in addition, Bromus ircutensis shows lunch hour phenomenon more obvious than Bromus ciliatus^Bromus inermis.3. The pollen fertility rate showed a obviously downward trend with the extension of the storage time. The pollen viability of the Bromus ircutensis and the Bromus inermis is the longest under the storage conditions at the 4～6.4 ℃. The energy storage of the Bromus ciliatus pollen viability is much longer at low temperatures under 0-2 "C.The pollen lifetime of them are longer under the two storage temperatures than the normal temperature (25～30 ℃).4. Through the squash of root tip cells, observed number of chromosomes. The number of cells had 25-31 chromosomes accounted for 89.74%. Bromus ircutensis Kom. somatic cells chromosome numbers initially identified were 28, was a tetraploid (2n=4x=28) plant.