Mechanisms Of Genotype Differences In Phosphorus Efficiency Of Spring Wheat

Phosphorus is one of necessary nutrient elements for plant growth, which plays an irreplaceable role in agricultural production, Phosphorus is named as "energy element" of plant necessary nutrients.Phosphorus is the important component of many compounds (nucleic acids, proteins, phospholipids, ATP, etc.) in plant.Furthermore, Phosphorus participate in physiological and biochemical processes of the plant, and it plays an important role in promote plant growth, development and metabolism. P resources are becoming depleted, So biology way has an important scientific and practical significance in enhance the potential of plant and improve phosphorus use efficiency of soil and fertilizer.Using 22 spring wheats of Xinjiang (xingchun 2~xingchun 23) as the test materials.Comparison their phosphorus nutrition characteristics and plant individual traits under the treatment of normal and low phosphorus conditions with pot experiment during 2007-2008. Classification some high and low phosphorus efficiency wheat varieties.During 2008-2009, Study on the physiological and biochemical characteristics at seeding stage and phosphorus accumulative law in the whole life of high and low phosphorus efficiency genotypes were selected by screening in pot experiment. The main results were shown as the following:1.Under low-phosphorus conditions, with plant phosphorus use efficiency has different improvement in varying degrees, the 22 tested wheat varieties plant traits and total phosphorus and phosphorus accumulation in different plant organs had reduced in varying degrees, comparing to their controls respectively. With relative grain yield as an indicator, the 22 varieties were evaluated.Four wheat varieties are high phosphorus efficiency varieties, 8 mid phosphorus efficiency species, and 10 phosphorus inefficiency species. Plant height, tillers per plant and grains per spike have significant or very significant positive correlation with phosphorus efficiency, which can be used as the distinction indicators between high and low phosphorus efficiency.2.Under different phosphorus conditions, phosphorus content in wheat grain, chaff, leaves and stem is grain> chaff> leaf> stem, indicating that with the phosphorus content of grains tends to be normal , phosphorus content in leaves and stem reduced to improve fertilizer use efficiency. Phosphorus use efficiency in wheat is higher under low phosphorus conditions than that under normal. This shows that the low-phosphorus stress can promote wheat phosphorus utilization.3. Study on root morphology and root exudates in seedling stage showed: In order to adapt to low-phosphorus, the wheat varieties with different phosphorus efficiency by changing the root length, root volume, root/shoot dry weight, root acid phosphatase activity, root activity and other physiological features to increase the absorption and utilization of phosphorus, the different genotypes with different magnitude of the changes.4. Study on membrane protective enzyme in leaf of different wheat genotypes showed: Under low phosphorus stress, The high phosphorus efficiency varieties by maintaining a lower malondiaidehyde (MDA) and a higher superoxide dismutase (SOD), peroxide enzyme (POD) activity .The above results indicated the high phosphorus efficiency wheat varieties with stronger self-protection capability than low phosphorus efficiency wheat varieties under low-phosphorus stress.5.Study on phosphorus nutrition of varieties with different phosphorus efficiency at the whole growth period showed: At the mid and late period, the total phosphorus cumulative amount of has a greater increase than at pre period.This showed wheat has a relatively strong ability to absorb phosphorus at the mid-and late period.Under low phosphorus conditions, thd high phosphorus efficiency varieties showed higher total phosphorus in different growth period and different growth stage.This showed that the high phosphorus efficiency varieties with strong adaptability of low-phosphorus environment.