[Effects of nitrogen application level on photosynthate distribution of Korla fragrant pear trees].

Using C pulsed labeling technique, we examined the biomass and carbon accumulation of different organs as well as the distribution characteristics of C assimilate of 6-year-old Korla fragrant pear trees under three nitrogen application levels, ., 150, 300, and 450 kg N·hm (marked as N, N, and N, respectively). Results showed that the biomass, carbon accumulation, C fixation and leaf assimilation capacity of the whole pear tree increased while root to shoot ratio decreased with increasing nitrogen application.

[Characteristics of absorption, utilization, and distribution of N-urea for Korla fragrant pear in spring].

Six-year-old Korla fragrant pear trees were fertilized with N-labelled urea before early bud stage to examine the absorption, distribution, and utilization of urea. Results showed that there was a significant difference of N distribution rate in organs at different growth stages. N was pre-ferentially distributed in the roots , with Ndff (N amount absorbed from the fertilizer contribution rate of the total nitrogen organ) being the highest in roots following by new shoots at full-bloom stage.

[Responses of main characters of root system to salt stress among cotton varieties with diffe-rent salt tolerance].

A pot experiment was carried out to test the effects of salt levels on root morphology as well as the relationship between root morphology and salt tolerance with four cotton cultivars (salt-sensitive cultivar CCRI45, weak salt-resistance cultivar XLZ17, moderate salt-resistance cultivar XLZ13 and salt-resistance cultivar CCRI35). Results showed that dry mass and K/Na ratio of cotton root and leaf were significantly reduced by salt stress. Dry mass of root and leaf and K/Na ratio of root of cultivars XLZ13 and CCRI35 were 69.

[Effects of phosphorus fertilization on biomass accumulation and phosphorus use efficiency of trellis-cultivated melon].

A field experiment applying six rates of P fertilizer (P2O5, 0, 150, 225, 300, 375 and 450 kg . hm-2, respectively) was conducted to investigate the effects of P fertilization on dry matter accumulation (DMA), P uptake and accumulation (PUA) and P use efficiency (PUE) of trellis-cultivated melon. Results showed that, P application increased DMA and PUA, for 150 and 225 kg P2O5 .

[Research on the relevance of earthworms inducing soil Cd2+ absorbed by perennial ryegrass].

Through the method of simulating the heavy metal pollution in farmland, the graphite oven (GF-990) atomic absorption was used for analyzing the regulations of the earthworms inducing the soil Cd2+ absorbed by the perennial ryegrass. The result indicated: (1) under the circumstance of the soil Cd2+ density of 3-6 mg x kg(-1), the positive relevance appeared extremely remarkably that the contents of Cd2+ in underground portions of the perennial ryegrass relate to the earthworm quantity (r = 0.883 2-0.

[Comparative analysis of endogenous hormones between two species of Ammopiptanthus seedlings around germination and under Pb2+ stress].

The changes in three endogenous hormones, phytohormones gibberrelic acid (GA3), indoles-3-acid (IAA) and abscisic acid (ABA), were studied around germination and under tress of different density of Pb2+ between two species of Ammopiptanathus. It was found that (1) around germination, in Xinjiang Ammopiptanthus the rate IAA decreased 77.80%, and the rate of ABA decreased 98.