Study On Drought-resistant Characteristics Of Four Kinds Of Mosses

Drought is not only a matter of the world but also one serious risk to China, which isrestricting the economic development of our country. It not only threaten the northern aridand semi-arid regions which are lacking of water,but also the southern humid and semi-humidregions which are abundant of rain but come up seasonal drought, that the rain capacity isuneven, all this causes the alternate formation of drought and flood. To deal with thisworldwide problem, our nation has carried out lots of manpower and material resources onstudying drought-resistant mechanism of plants, searching for drought resisting theory andevaluating drought resistant ability between different plants to direct the current productionand daily life.In this paper, we have chosen mosses as the research objects, for that the moss is a kindof transitional plant with extremely extensive distribution and high strength resistance, thereare significant advangtages to study its drought-resistant mechanism which is unique to otherplants.After studying the ultrastructure of Racomitrium japonicum and Grimmia pilifera, thedrought stress to R. japonicum, G. pilifera, Tortula ruralis and Rhytidiadelphus triquetrus,physiology and biochemistry after rehydration and photosynthetic physiology, we concludedthat:1. After8-48hours’ rehydration then observed the the ultrastructure of R. japonicum andG. pilifera, we discovered that chloroplasts recovered relatively intactly, with clear doublelayers coating, abundant thylakoid layers and grana. Membrane system was integrate, GOMswere obviously increased and arranged together. The two kinds of mosses possess relativehigh photosynthetic efficiency during this period (RWC=38.12%-48.00%).2. Stress resistence of R. triquetrus is relative weak, for it would die caused by droughtin the extremely arid condition.3. After the one-year continuous drought stress of silica gel, we found that R. japonicum,G. pilifera and T. ruralis all possess a good ability of drought-enduring and obvious physicalreactions in the comprehensive evaluation of physical signs. Drought-enduring ability of T.ruralis is better than that of R. japonicum and G. pilifera, however R. japonicum is similar indrought-enduring ability to the G. pilifera. 4. During the ten days’ rehydration experiment, in the process of injury, restoration andcompensation, we can conclude that water retaining capacity of T. ruralis is better than that ofR. japonicum and G. pilifera, antioxidant recovery ability of G. pilifera is better than that ofR. japonicum and T. ruralis, and the restoration and compensation capacity of osmoticadjustment substances of R. japonicum is better than that of G. pilifera and T.ruralis byphysical signs comprehensive evaluation.5. During the photosynthetic property comprehensive evaluation, water retainingcapacity and photosynthetic efficiency of T. ruralis are obviously better than those of R.japonicum and G. pilifera and photosynthetic efficiency of R. japonicum is slightly better thanthat of G. pilifera, water retaining capacity of G. pilifera is slightly better than that of R.japonicum.