Tobacco Research Institute of Guizhou, Guiyang 550081, China)AbstractThe differences among eight tobacco culitvars or lines (Nicotiana tabacum) in autotoxicity of root exudates were investigated using bioassay. Root exudates of the eight tobacco cultivars or lines were collected and used to determine the effects of them on seed germination and seedling growth. The results showed that for most cultivars, fresh and dry mass, leaf and root length were increased at low concentration of exudate and reduced at high concentration of one. A cultivar, Qianxi 1 showed the greatest inhibition for all growth parameters above. While the breeding line, No.1 was quite particular in its response to root exudate, in that all growth parameters showed increase, even under the highest concentration of root exudate. Germination rate of the new lines No.7, No.1 and cultivars Yunyan 85 and Chunlei 3 were promoted, while that of other cultivars was inhibited by root exudates. It may be concluded that that the autotoxicity differs among tobacco genotypes, suggesting that it is possible in breeding program to develop the cultivars with less allelopathy.

Effects of parasitic plant Cuscuta australis on the growth of three invasive plants, including Erigeron annuus, Chenopodium ambrosioides and Bidens pilosa, were investigated in a common garden experiment The parasitic C. australis decreased significantly the root length of invasive E. annuus, but had no significant effect on that of invasive C. ambrosioides and B. pilosa. The parasitic C. australis decreased significantly the stem length and total length of three invasive plant species, in which the stem length and total length of E. annuus reduced up to 67.4% and 63.4%, respectively. The parasitic C. australis decreased significantly the root, leaf, stem, aboveground and total biomass of three invasive plants, in which the root, stem and leaf biomass of E. annuus reduced up to 46.8%, 81.7% and 65.2% respectively. The parasitic C. australis increased significantly the root / shoot ratio of three invasive plants.

By using polymerase chain reactionrestriction fragment length polymorphism (PCRRFLP) based Sgene identification system and DNA sequencing technology, the Sgenotypes of ‘Chuxialü’ and ‘Cuiyu’ (Pyrus pyrifolia Nakai. cvs., two of the F1 progenies selected from ‘Xizilü’ × ‘Cuiguan’) were confirmed as S3S4, respectively. The results of fluorescence microscopic observation of pollen germination dynamics in situ and artificial pollination experiment showed that, both ‘Chuxialü’ and ‘Cuiyu’ had middle strength of selfincompatibility, but the crosscompatibility between them were incomplete; the selfincompatibility strength of ‘Cuiguan’ was high, while its crosscompatibility with ‘Chuxialü’ and ‘Cuiyu’ was observed.

Leaf anatomy of nine species in Carex sect. Rhomboidales (Cyperaceae) from China was studied by the method of paraffin section. These nine species shared some common characters as follows: 1) The outline of leaf transverse section was Vshaped or almost Vshaped and the aircavities between vascular bundles were well developed; 2) The bulliform cells on the midrib were also well developed, and midrib vascular bundles were surrounded with sclerenchyma; 3) The adaxial epidermal cells were larger than those of abaxial surface, and the mesophyll cells all appeared different degree of differentiation; 4) Both adaxial and abaxial epidermal cells were oblong and their anticlinal walls were deeply undulate, and the epidermal appendage was prickle. However, there were also some diagnostic characters among the species, viz. the layer of bulliform cells, the layer of the mesophyll cells, the developed condition of the sclerenchyma, the distribution pattern of stoma on abaxial epidermis, the stomatal density, and stomatal index etc. A key based upon the leaf anatomical characters to the nine species was provided as well.

Aiming to develop the transdermal formulation of mequindox microemulsion (M-ME) and evaluate its stability and the transdermal permeability in vitro skin, the best prescription was optimized through the pseudoternary phase diagrams, and the M-ME was prepared by phase transformation.The drop shape was reviewed by the transmission electron microscope (TEM). The average droplet size and polydispersity index (PDI) of M-ME were measured by photon correlation spectroscopy (PCS) using a Zetasizer Nano ZS instrument. Zeta potential measurements were carried out using the same equipment. The stability was also evaluated through the constant temperature acceleration test, and the transdermal effect was studied on epidermis of mice in vitro. The result showed that the mequindox had the maximum solubility in cinnamaldehyde among all the tested oils, and cremophor RH40 was the optimal surfactant.The M-ME containing cinnamaldehyde and RH40 was clear and transparent yellow fluid with excellent liquidity. The TEM presented it as spherical drops, and their average diameter was (13.9 ± 0.3) nm with PDI at 0.060 ± 0.005.At 25 ℃，the zeta potential of the M-ME diluted 5 times was (9.4 ± 0.4) mV with pH of 5.1 ± 0.2.High speed centrifugalization and low or normal temperature did not affect the M-ME, while its color changed from yellow to red at 60 ℃ without medicine separating out，indicating that M-ME satisfied the criteria of microemulsion formulation with fine stability. The permeability coefficients （Kp × 10^-3） of M-ME with no azone，M-ME with 2% azone and M-ME with 5% azone were (12.701 ± 0.012), (12.207 ± 0.021) and (10.796 ± 0.065) cm·h^-1 respectively, while the Kp × 10^-3 of mequindox aqueous solution was (4.908 ± 0.034) cm·h^-1, indicating that the transdermal permeability of M-ME exceeded its aqueous solution with significant difference (P < 0.01), and there was no need to add azone to M-ME as transdermal enhancer.

In order to establish the immunoassay method of dicamba（DIC），the diimine carbonization methods were used to synthesize immunogen and coating antigen by dicamba being conjugated to ovalbumin (OVA) and bovine serum albumin (BSA), respectively. The polyclonal antibodies against dicamba were prepared through immunizing New Zealand white rabbits with the immunogen. The enzymelinked immunosorbent assay (ELISA) titer of the antibody was 1∶1.28×105. The percentages of the antibody cross reactivity with other analogues of dicamba (2,3,5-trichlorobenzoic acid, 2,3,6-trichlorobenzoic acid and 2-amino-3,5-dichlorobenzoic acid) were all less than 01%. An indirect competitive ELISA (ciELISA) was developed for dicamba detection, with coating antigen and polyclonal antibody diluted at 1∶8000 and 1∶80000. The lineal range of the assay for detecting dicamba was 1 to 100 ng·mL^-1, with the detection limit (IC20) of 1-779 ng·mL^-1. The regression equation was y = 8.6844 ln x+15.001， R2=0.9944. When dicamba addition value was from 5 to 30 μg·kg^-1 in the recovery tests, the recovery rate of dicamba in corn meal and wheat flour blank samples ranged from 53.08% to 92.37%, and 66.5% to 94.63%, respectively.

The full length of stressinducible protein I (STI1) gene cDNA was cloned from Miichthys miiuy based on the obtained EST sequence using rapid amplification of cDNA ends polymerase chain reaction (RACE-PCR). The STI1 gene cDNA consisted of 2194 nucleotides including 5 untranslated regions (UTR) of 31 nucleotides, 3 UTR of 634 nucleotides and open reading frame with 1629 nucleotides encoding 542 amino acid residues. The molecular structure of STI1 consisted of five potential casein kinase II phosphorylation sites, one polyproline stretch, two nuclear localization signals and nine tetratricopeptide repeats (TPR). The amino acid sequence of the STI1 gene shared 76.5%-94.3% identity with those of previously reported other species STI1 gene including conserved eight cysteines. Phylogenetic tree analysis based on amino acid sequences of STI1 gene generated by neighborjoining method suggested that four teleosts clustered together, and were close genetic relationship between M. miiuy and Pseudosciaena crocea. Realtime PCR showed that the STI1 gene was mainly detected in muscle and kidney.

A field experiment was conducted to investigate the dynamic characteristics of SPAD reading during growth stage of rice and the spatial distribution of SPAD value of four leaves from the top on main stem of rice using the chlorophyll meter SPAD under three different fertilization programs and six different N application rates at tillering stage, booting stage and heading stage of rice. The results showed that the greenness of rice leaf was regularly changed as “black-yellow” alternation ways through the whole growth period of rice, and the sensitivity of the fourth leaf from the top to N was highest, giving it as the most ideal indicator of rice leaf position when using SPAD value to diagnose N status. Furthermore, the difference between SPAD values of the adjacent leaf and nitrogen application rates showed that SPAD_L4-L3was highly related to the plant nitrogen content. With the increasing plant nitrogen content, the difference in SPAD value between the fourth leaf and the third leaf decreased, regardless of fertilizer application condition and development stage. Thus, SPAD_L4-L3 value could be used as a suitable indicator for rice plant nutrition status at whole stage.

The effects of five hydroponic nutrient solutions, Hoagland formula, Japanese Yamazaki formula (JY), Japanese Garden formula (JG), South China Agricultural University (SCAU) formula B for leafy vegetables and England Hewitt formula (EH) on the biomass production and nutritional quality of aeroponically grown lettuce (Lactuca sativa L.) were compared. The results showed that the pH levels of five solutions were increased to some extent during the treatment. The highest increase in pH was observed in EH, while the lowest was in SCAU formula B. Plants grown in SCAU formula B solution showed high fresh and dry mass of roots and shoots, compared to the plants grown in other four nutrient solutions. Furthermore, The plants treated with SCAU formula B showed the highest ascorbic acid content, FRAP (ferric reducing/antioxidant power) value, DPPH (1,1-diphenyl-2-picrydrazyl) radical scavenging rate, as well as soluble sugar content in the leaves among all nutrient solution-treated plants. However, the soluble protein content was comparable to that of JG-treated plants, while the glutathione contents was lower than that of JG-treated plants. Furthermore, the nitrate contents of stems and leaves of SCAU formula B-treated plants were significantly lower than those of EH and Hoaglandtreated plants, but a little higher than those of JG and JY-treated plants. These results indicate that aeroponically grown lettuce in SCAU formula B solution produce high biomass yield, high antioxidant content and antioxidant activity, and low nitrate content, suggesting that SCAU formula B is the most ideal nutrient solution for aeroponically grown lettuce, whereas EH and JY formulas are unsuitable for aeroponically grown lettuce.

Effect of foliar spraying uniconazole on growth and nitrogen metabolism of soybean ［Glycine max (L.) Merr.］ cultivar ‘Gongxuan 1’ at different nitrogen levels was studied under maizesoybean relay strip intercropping system. The results showed that, uniconazole had strong morphological effects to control excessive vegetative growth of soybean under different nitrogen levels, which could decrease plant height, the first internode length, the ratio of plant height and stem diameter, increase stem diameter, branch number and dry matter mass of shoot; uniconazole had significant physiological effects to promote nitrogen metabolism of soybean plants, which could increase nitrogen content of shoot and root, the amount of bleeding sap, NO3^--Ncontent and NH4⁺-Ncontent in bleeding sap, the total amino acid content and the contents of amino acids such as Asp and Thr, decrease the ratio of NH4⁺-N and NO3^--N, the contents of amino acids such as Glu and Gly. All results showed that the excessive vegetative growth of shoot was suppressed and the uptake of nitrogen, assimilation, amino acid synthesis and transportation were promoted by foliar sparing uniconazole with a moderate concentration of 60 mg·kg^-1 under low nitrogen level (30 kg·hm^-2), or a low concentration of 30 mg·kg^-1 under moderate nitrogen level (32.4 kg·hm^-2), or the higher concentrations of 60 or 90 mg·kg^-1 under higher nitrogen level (64.8 kg·hm^-2).

A field experiment was conducted to study the effects of balanced fertilization on the crop production and soil nutrient status within two crop growing seasons under longterm greenhouse eggplantrice rotation system. The results showed that N was the main limited factor for soil nutrients at the current stage, while P and K were not the case for crop yields, nutrient absorption and contents in two crop growing seasons. The total accumulation of N overground in optimum treatment (OPT) during the rotation period was 314.2 kg·hm^-2, which accounted for 63.0% and 72.9% of supplying amounts of soil N in the period of greenhouse eggplant and rice respectively, and the corresponding apparent use efficiency of N was only 10.85% and 24.9%. The total accumulation of P₂O₅ and K₂O overground during the rotation period were 159.5 and 543.9 kg·hm^-2, respectively. The supplying amounts of soil P and K both exceeded 90%, and the apparent use efficiency of P and K was 11.5% and 8.6%, respectively. Both decreasing the N application and delaying the N application time to the rice season could enhance the total nutrient absorption. The suitable nitrogen application rates for the greenhouse eggplant and rice were 450 and 150 kg·hm^-2, respectively, decreasing by 55% and 33.3% as compared with the traditional fertilization. The paddyupland rotation could effectively utilize the soil nutrients which were accumulated by the heavy fertilization in the greenhouse season, but the soil nutrients still had the tendency to move into deeper soil layers.

To understand the effects of different cropping systems on soil exchangeable Mg, samples of soil profiles under six types of different cropping systems were collected from longterm location experiment station, Changwu County, Shaanxi Province. The changing conditions of exchangeable Mg in soil profiles of different cropping systems under the condition of 22 years' continuous application of NP chemical fertilizer in Loess Plateau were studied. The results showed that the exchangeable Mg occurred eluviation and accumulation in soil profiles of different cropping systems. The peak was at 60100 cm soil depth with the values of 263, 255, 250, 248, 244 and 243 mg·kg^-1 under the sainfoinwheat (2 a) rotation, wheat (2 a) + milletmaize rotation, maizewheat (2 a) + millet rotation, peawheat (2 a) + millet rotation, wheat succession and peawheat (2 a) +maize rotation systems, respectively. The cumulative amounts of exchangeable Mg in soil profiles (0200 cm) under the sainfoinwheat (2 a) rotation, wheat (2 a) + milletmaize rotation, peawheat (2 a) + millet rotation, maizewheat (2 a) + millet rotation, peawheat (2 a) + maize rotation and wheat succession were 6152, 5855, 5853, 5755, 5740 and 5347 kg·hm^-2, respectively. The results suggest that the different crops and cropping systems have effects on difference of exchangeable Mg distribution and accumulation in soil profile.

In order to probe best application methods of super absorbent polymer in spring wheat production in Hetao irrigation district, Inner Mongolia, with no BJ2101-L super absorbent polymer for control at spring wheat sowing, BJ2101-L super absorbent polymer was applied with three methods of furrowing, mixing and broadcasting, and the effects of BJ2101-L super absorbent polymer on soil moisture, soil temperature and spring wheat growth status were determined at different growth stages. The result showed that all application methods increased the soil moisture, especially in florescence absent of irrigation, and the effect of furrowing was stronger, and the broadcasting was weaker. All application methods reduced the soil maximum temperature, increased the minimum temperature, and decreased the soil diurnal temperature changing, reduced the daily mean temperature; meanwhile broadcasting had greater influence on the earth's surface temperature, and furrowing had greater influence on the 10 cm soil layer temperature. Furrowing, mixing and broadcasting promoted spring wheat root distribution to deep soil, and increased the roots and total biomass. Compared with the control, the yields of furrowing, mixing and broadcasting were increased by 22.6%, 16.3%, 8.0%, respectively. All application methods improved the water use efficiency, water production rate and water production rate of irrigation, in which the effect of furrowing was stronger, and the broadcasting was weaker. The results above indicate that furrowing is the optimum application method of BJ2101-L super absorbent polymer in Hetao irrigation district at spring wheat sowing.

The components and physicalchemical properties as well as their annual changes of rural household solid wastes were investigated in Liandu district, Lishui city, Zhejiang Province, as a representative of mountaineous rural areas. A longterm experiment was conducted to assess the risk of heavy metal pollution and the potential of biodegradable organic waste fertilization in soybean-soybean-broad bean cropping system. The results showed that the biodegradable organic waste was the major portion of rural household wastes, and the average proportion was 4364%. Nutrien content (N + P₂O₅ + K₂O, dry mass) was about 3%, and organic matter average content was 24.9%, and their annual changes were very little. But the biodegradable organic wastes contained some heavy metals, and the contents changed greatly. Compared with conventional chemical fertilizer, application of waste organic fertilizer did not obviously change the yield of soybean in the first and second crop, and significantly increased the yield of broad bean in the third crop. Applying waste organic fertilizer had no significant effect on qualities and heavy metal contents of soybean and broad bean, was safe. Application of waste organic fertilizer significantly improved pH value, organic matter and total nitrogen contents of soil, also could enhance the heavy metal contents which had a gradual accumulation trend. Therefore, establishing a set of suitable classification and collecting system of rural household wastes, will effectively decrease amount of waste. Longterm application of waste organic fertilizer could increase agriculture production and improve soil fertility, but it also brought risk of heavy metal pollution, so application amount and time of waste organic fertilizer should be monitored and controlled.

In order to solve the potential environmental and ecological problem that was aroused by the enormous amounts of the invasive aquatic biomass, a fast disposal process that directly subcritical hydrothermal conversion of those fresh aquatic biomass was developed according to the hydrothermal technology and the characteristic of high water content of aquatic biomass. This process was operated on a autoclave with a 3 L capacity, and the effects of hydrothermal conditions of different temperatures (150~280 ℃) and different retention time (0~60 min) on hydrothermal conversion of two model aquatic biomass were concentrated on. The two model aquatic biomass were water hyacinth and a mixed biomass sample (water lettuce and green waste of flower market), respectively. The results showed that this process could convert successfully the two model aquatic biomass into ecological organic fertilizer after treatment. The yield of solid product, which was reutilized as organic fertilizer, decreased with increasing reaction temperature and retention time. Besides, the high content of lignocelluloses was fast decomposed with an elevated reaction temperature and a longer retention time, but the lignin could hardly be decomposed at the given reaction temperature and time of this test. The analysis result of fertilizer nutrient in solid product also showed that these two organic fertilizers were rich of humic acid and nutrients of nitrogen, phosphorus and potassium, in which the highest total humic acid amounts could reach as much as 38.29% (for water hyacinth) and 41.76% (for mixed biomass), and the total nutrient amounts were not less than 4.1% (for water hyacinth) and 3.0% (for mixed biomass) among the all treatments.In conclusion, as using this hydrothermal process, the enormous amount of aquatic biomass can be effectively converted into organic fertilizer, and bring about great ecological and socioenvironmental benefits.