Studies On Physiological And Biochemical Properties Of Phosphorous Uptake And Utilization Of Various Wheat Varieties (genotypes)

Using 16 wheat varieties as experimental materials, a study on phosphorous uptake and utilization was conducted during 1998-1999. Using 4 screened typical wheat varieties, i.e. 2 P-efficient varieties, 1 P-inefficient variety and 1 moderately efficient variety, a study on physiological and biochemical properties of P uptake and utilization was conducted during 1999-2000. A study with 2 vheat hybrids, Fl-i and Fl-2. was conducted during 2000-2001. The main results were shown as the following: 1. Except that P utilization efficiency was increased, the plant traits of mature period, P concentration and P content per plant of different growth stage, the community growth characters of different period, of the 16 wheat varieties were all decreased under low P stress. Compared with their own CK, the P utilization efficiency was increased from 105% to 223%, plant traits at maturity were decreased to 47.72%-95.24% of CK, P concentration reduced to 44.94% of CK at the lowest point, P content per plant reduced to 27.60% at the low point. Using the ratio of the grain weight per plant under low P stress to their own CK, 16 wheat varieties were classified into 3 groups: 4 P efficient wheat varieties, 9 moderately efficient wheat varieties and 3 inefficient wheat varieties. Plant height of mature period, spike number per plant and kernel numbers per spike were significantly positive-related to P efficiency. The community growth characters (except for photosynthetic potential )from jointing to earing were significantly positive-related to P efficiency, too. So that all the above characters can be used as the indices to select P efficient wheat varieties (genotypes). 2. Except that the acid phosphate activity ( APA ) was increased, the photosynthetic rate ,photosynthetic physiological characteristics, root traits and TTC activity re all decreased under lov P stress. Compared with their own CK, all the characteristics of the P-efficient wheat varieties reduced less, the moderately P efficient wheat variety reduced more, P inefficient wheat variety reduced most. Correlation analysis showed that the chorophyll content and soluble protein content at jointing, RuBPcase activity at spiking and Ca2/Mg2TPase activity at jointing and spiking were significantly positive-related to P efficiency . So that all the above characters can be used as the indices to select P efficient wheat varieties (genotypes). APA was significantly positive-related to P-utilization efficiency. TTC activity was significantly positive-related to P-uptake efficiency. So, they can be used as the indices of P-utilization efficient and P- utilization efficient wheat varieties respectively. 3. Some indices of the two wheat hybrids Fl-I and F 1-3, such as photosynthetic physiological characteristics, yield and characteristics of P uptake and utilization, were improved differently. These indices of Fl-i and FI-3 were higher than those of their parents. The AH and SH of Fl-3 were higher than those ofFl-l. According to the results, some problems such as the conception of P-efficiency, the screening indices of P efficiency wheat varieties and the mechanism of P efficient wheat varieties were discussed.