Cadmium accumulation in the edible parts of different cultivars of radish, Raphanus sativus L., and carrot, Daucus carota var. sativa, grown in a Cd-contaminated soil.

Cadmium accumulation among 12 cultivars of radish (Raphanus sativus) and 10 cultivars of carrot (Daucus carota var. sativa) was studied in a Cd-contaminated soil. The Cd concentration in the edible parts of radish and carrot ranged from 0.

Influence of iron plaque on uptake and accumulation of Cd by rice (Oryza sativa L.) seedlings grown in soil.

Iron plaque is ubiquitously formed on the root surfaces of rice. However, little is known about the role of iron plaque in Cd movement from soil to the plant aboveground parts. A pot experiment was conducted to investigate the influence of iron plaque in Cd uptake and accumulation by rice seedlings in soil.

[Application of ICP-MS/ICP-AES to detection of 22 trace elements in fruits of elm].

Fruit of elm has been a popular food in Chinese county for many years. With the rapid development of food nutrition and food safety, more and more people begin to pay attention to its content of trace elements and heavy metals. The wild fruit of elm was studied by ICP-MS/ICP-AES to detect the 22 trace elements.

Does cadmium play a physiological role in the hyperaccumulator Thlaspi caerulescens?

The southern French (Ganges) ecotype of Thlaspi caerulescens J & C Presl is able to hyperaccumulate several thousand mg Cd kg(-1) shoot dry weight without suffering from phytotoxicity. We investigated the effect of Cd on growth and the activity of carbonic anhydrase (CA), a typical Zn-requiring enzyme, of T. caerulescens in soil and hydroponic experiments.

[Application of ICP-MS/ICP-AES to detecting factors influencing the quality of Nanfeng orange].

Nanfeng orange is a world famous fruits, but its quality changes remarkably with the producing area. The present paper studied the contents of heavy metal mineral elements and microelements in soil planting Nanfeng orange by ICP-MS/ICP-AES and in order to find the dominant factors that affect the quality of Nanfeng orange in soil. The results showed that the contents of B, P, K, Mg and Ca, especially B, P and K were much higher in soil where the quality of Nanfeng orange is palatable than those where Nanfeng orange is unpalatable; but the contents of Fe, Mn, Si, Cu and Zn were lower in soil where the quality of Nanfeng orange is palatable than those where Nanfeng orange is unpalatable.

Tobacco plants can use nitrogen taken up before mechanical wounding to synthesize nicotine afterwards.

Mechanical wounding stimulates nicotine synthesis in tobacco plants. In the practice of tobacco production, most nitrogen (N) is taken up before removal of the shoot apex, while nicotine is mainly synthesized afterwards. Since N is required for nicotine synthesis, it is interesting to know whether plants can use N taken up before removal of the shoot apex to synthesize nicotine after wounding.

[Appropriate soil nitrate N content for a winter wheat/summer maize rotation system in North China Plain].

A field experiment with 12-level N fertilization in winter wheat growth season and zero-N in summer maize growth season was conducted to study the appropriate soil nitrate N content for a winter wheat/summer maize rotation system in North China Plain. The results showed that when the soil mineral N content before sowing was higher, a split application of 150 kg N x hm(-2) in winter wheat growth season could meet the N demand of both winter wheat and summer maize in the rotation system. The N use efficiency of winter wheat in different N treatments was only from 11% to 23%, while the residual N use efficiency of summer maize ranged from 30% to 52%.

Inhibition of maize root growth by high nitrate supply is correlated with reduced IAA levels in roots.

The plant root system is highly sensitive to nutrient availability and distribution in the soil. For instance, root elongation is inhibited when grown in high nitrate concentrations. To decipher the mechanism underlying the nitrate-induced inhibition of root elongation, the involvement of the plant hormone auxin in nitrate-dependent root elongation of maize was investigated.

Multiple signals regulate nicotine synthesis in tobacco plant.

After wounding of tobacco plants, roots synthesize a large amount of nicotine to be transported to the shoot. Jasmonic acid (JA) acts as a long-distance signal between the wounding stimulus and response in tobacco plants. In addition, another phloem-mobile signal (auxin) plays a role in the transmission of the message triggered by wounding.

Diversity enhances agricultural productivity via rhizosphere phosphorus facilitation on phosphorus-deficient soils.

Intercropping, which grows at least two crop species on the same pieces of land at the same time, can increase grain yields greatly. Legume-grass intercrops are known to overyield because of legume nitrogen fixation. However, many agricultural soils are deficient in phosphorus.

Seasonal temperatures have more influence than nitrogen fertilizer rates on cucumber yield and nitrogen uptake in a double cropping system.

Two-year greenhouse cucumber experiments were conducted to investigate seasonal effects on fruit yield, dry matter allocation, and N uptake in a double-cropping system with different fertilizer management. Seasonal effects were much greater than fertilizer effects, and winter-spring (WS) cucumber attained higher fruit yields and N uptake than autumn-winter (AW) cucumber due to lower cumulative air temperatures during fruit maturation in the AW season. Fertilizer N application and apparent N loss under recommended N management (Nmr) decreased by 40-78% and 33-48% without yield loss compared to conventional N management (Nmt) over four growing seasons.

[Dynamics of Cd adsorption on rice seedlings root surface with iron coating and Cd uptake by plant].

In a water culture experiment, rice seedlings were grown in a nutrient solution containing 10 micromol Cd x L(-1), and harvested after different durations of growth. Two treatments were installed, i. e.

Transpiration, and nitrogen uptake and flow in two maize (Zea mays L.) inbred lines as affected by nitrogen supply.

Background And Aims: The influence of two nitrogen (N) levels on growth, water relations, and N uptake and flow was investigated in two different inbred lines of maize (N-efficient Zi330 and N-inefficient Chen94-11) to analyse the differences in N uptake and cycling within a plant.

Methods: Xylem sap from different leaves of the inbred lines cultured in quartz sand was collected by application of pressure to the root system. Plant transpiration was measured on a daily basis by weighing five pots of each of the treatments.

Nicotine synthesis in Nicotiana tabacum L. induced by mechanical wounding is regulated by auxin.

The effects of different kinds of mechanical wounding on nicotine production in tobacco plants were compared, with sand or hydroponics culture under controlled conditions. Both removal of the shoot apex and damage of the youngest unfolded leaves nos 1 and 2 by a comb-like brusher with 720 punctures caused an increase in nicotine concentration in whole plants at day 3, and reached its highest level at day 6. The nicotine concentration induced by excision of the shoot apex was much higher than that induced by leaf wounding.

Nutritional and osmotic roles of nitrate in a euhalophyte and a xerophyte in saline conditions.

The effects of salinity and nitrogen (N) on growth and the role of NO3- in osmotic adjustment in the leaf-succulent euhalophyte Suaeda physophora and the stem-succulent xerophyte Haloxylon persicum were evaluated. Seedlings were exposed to 1 or 300 mm NaCl in 0.05, 1 or 10 mm NO3- -N treatments for 24 d.

Comparative proteome analyses of maize (Zea mays L.) primary roots prior to lateral root initiation reveal differential protein expression in the lateral root initiation mutant rum1.

The embryonically preformed primary root is the first root type of maize that emerges after germination. In this study the abundant soluble proteins of 2.5-day-old primary roots of wild-type and lateral root mutant rum1 seedlings were compared before the initiation of lateral roots.

[Estimation parameters of nitrogen balance in stock farming system of China].

The study of nitrogen (N) balance in stock farming system is the basis of nutrient management in animal husbandry production, and the determination of N cycling parameters is the foundation of this study. Through documents checking and data collecting, this paper analyzed the items and values of input/output parameters of N cycling in stock farming system, and ascertained the estimation parameters of N balance in the system, which could offer the theoretical foundation for nutrient management in animal husbandry production.

[Absorption and distribution of nitrogen from 15N labelled urea applied at core-hardening stage in winter jujube].

The study with pot experiment showed that at the rapid-swelling stage of winter jujube fruit, the percent of nitrogen derived from fertilizer (Ndff%) was the highest (10.64%) in fine roots, followed by new-growth nutritive organs. The absorbed urea-15N decreased in leaves and deciduous supers, and accumulated preferentially in root systems after harvest.

Utilization and management of organic wastes in Chinese agriculture: past, present and perspectives.

Recycling and composting of organic materials such as animal waste, crop residues and green manures has a long tradition in China. In the past, the application of organic manures guaranteed a high return of organic materials and plant mineral nutrients and thus maintained soil fertility and crop yield. As a result of rapid economic development coupled with the increasing urbanization and labour costs, the recycling rate of organic materials in Chinese agriculture has dramatically declined during the last two decades, in particular in the more developed eastern and southeastern provinces of China.

[Effects of N fertilization on winter wheat grain yield and its crude protein content and apparent N losses].

Field experiments were conducted at four sites in 2002 to study the effects of N fertilization on winter wheat yield and its crude protein content and apparent N losses. The results showed that at these sites, the N application rate for maximum grain yield was 0, 0, 79 and 118 kg x hm(-2), and that for maximum grain crude protein content was 122, 100, 127 and 174 kg x hm(-2), respectively. The residual nitrate-N content in 0 approximately 90 cm soil layer after harvest was linearly increased, while the apparent N losses during wheat growth season was exponentially increased with increasing N application rate.

Root distribution and interactions between intercropped species.

Even though ecologists and agronomists have considered the spatial root distribution of plants to be important for interspecific interactions in natural and agricultural ecosystems, few experimental studies have quantified patterns of root distribution dynamics and their impacts on interspecific interactions. A field experiment was conducted to investigate the relationship between root distribution and interspecific interactions between intercropped plants. Roots were sampled twice by auger and twice by the monolith method in wheat (Triticum aestivum L.

Utilization and management of organic wastes in Chinese agriculture: past, present and perspectives.

Recycling and composting of organic materials such as animal waste, crop residues and green manures has a long tradition in China. In the past, the application of organic manures guaranteed a high return of organic materials and plant mineral nutrients and thus maintained soil fertility and crop yield. As a result of rapid economic development coupled with the increasing urbanization and labour costs, the recycling rate of organic materials in Chinese agriculture has dramatically declined during the last two decades, in particular in the more developed eastern and southeastern provinces of China.

[Nitrogen balance and its effects on nitrate-N concentration of groundwater in three intensive cropping systems of North China].

Selecting three main intensive cropping systems of North China, i.e., wheat-maize rotation, plastic greenhouse vegetable, and apple orchard as test objectives, this paper studied their nitrogen (N) budget, soil nitrate-N accumulation, and year-round dynamics of groundwater nitrate-N concentration.

Strategies for adaptation of Suaeda physophora, Haloxylon ammodendron and Haloxylon persicum to a saline environment during seed-germination stage.

Background And Aims: Germination is very important for plant establishment in arid regions. The strategies taken by halophytes during the seed germination stage to adapt to saline environments in an arid zone were investigated in Suaeda physophora (euhalophyte), Haloxylon ammodendron (xero-halophyte) and Haloxylon persicum (xerophyte).

Methods: Seeds of S.

Role of nitrification inhibitor DMPP (3, 4-dimethylpyrazole phosphate) in NO(3-)-N accumulation in greengrocery( Brassica campestris L. ssp. chinensis) and vegetable soil.

The influence of nitrification inhibitor (NI) 3, 4-dimethylpyrazole phosphate (DMPP) on nitrate accumulation in greengrocery (Brassica campestris L. ssp. chinensis) and vegetable soil at surface layer were investigated in field experiments in 2002 and 2003.