Study on Plant Regeneration of Wheat Mature Embryos Under Endosperm-Supported Culture

To reveal the suitability of using mature embryos as an explant source in wheat tissue culture, mature embryos from eight common wheat cultivars （Triticum aestivum L. cv.） were cultured with or without endosperm to test their efficiency of callus induction and plant regeneration. When embryos were cultured together with endosperm （endosperm-supported culture, ES）, the percentage of callus induction was significantly lower than that when embryos were cultured in the absence of endosperm （non-endosperm-supported culture, NES）. This pattern was evident in most genotypes, regardless of whether 2 or 8 mg L^-1 2,4-D was added in the NES culture. However, in ES culture, more induced calli were differentiated into distinct green spots and they further developed into plantlets. Thus, more plants were regenerated in ES culture than in the NES treatment. Most of the eight tested genotypes showed a significant difference in callus induction rate and plantlet regeneration in both ES and NES cultures. In addition, the enzymatic activity of oxalate oxidase in the callus of ES culture condition was obviously higher than that in the callus of NES culture condition, suggesting that the activity of oxalate oxidase may be a parameter for selection of calli with potential for plantlet regeneration. These results indicate that wheat mature embryos are valuable explants for highly efficient callus induction and plant regeneration, if proper treatment and medium are used.     

家兔萱草根素中毒的病理学观察

给家兔灌服低剂量(6 mg/kg)、中剂量(12 mg/kg)和高剂量(24 mg/kg)的萱草根素,研究其对家兔的毒性作用。结果显示,家兔均发生以中枢神经系统紊乱为特征的中毒症状,且存在明显的量-效关系;中毒家兔大脑、小脑和脊髓的白质呈丝瓜络样,结构异常疏松,肾小管上皮细胞肿胀、破裂,视网膜节细胞萎缩,肝细胞肿胀,颗粒变性,脾脏、肺脏严重充血。表明萱草根素能引起家兔以中枢神经系统病变为主的全身性病理变化。     

十字花科蔬菜对蛞蝓生长发育的影响

在25℃、开灯1 h,关灯23 h(光照1L:23 D)、湿度20%~30%条件下,采用甘蓝、油菜、花椰菜、大白菜、小白菜饲养蛞蝓,研究蛞蝓的生物活性。结果表明:大白菜上蛞蝓的产卵前期、产卵量与其它4种蔬菜相比差异显著;用甘蓝饲养的蛞蝓平均每天增重量最大,为4.68 g,甘蓝上蛞蝓的种群趋势指数和平均体重增加值与其它4种蔬菜相比差异显著,小白菜和花椰菜上蛞蝓的种群趋势指数与油菜和大白菜相比差异显著。说明不同蔬菜对蛞蝓种群生命力的影响存在差异。     

石海椒愈伤组织诱导与增殖研究

对石海椒幼嫩叶片和茎段进行了愈伤组织的诱导增殖研究,以期探寻其诱导和增殖的最佳条件。结果表明:石海椒的叶片和茎段都能诱导出愈伤组织,但最佳外植体为叶片,叶片和茎段在0.1%升汞中适合消毒时间为6 min和10 min。叶片最适诱导培养基为B5+0.6 mg/L6-BA+2.0 mg/L NAA,增殖培养基为B5+0.6 mg/L 6-BA+1.25 mg/L NAA。基本培养基和生长调节剂对愈伤诱导的影响是NAA>6-BA>基本培养基。     

种植松口蘑richoloma matsutake的土壤的生态学特性

A 5－year study on the soil ecological environment of matsutake(Tricholoma Matsutake)growing areas near Changbai Mountains showed that several factors,such as climate,parent material,organism and landform,which form the soil ecosystem provided sutable ecological environment for the formation and growth of matsutake How to improve the construction and function of the soil ecosystem in order to utilize the natural resource continumously was also studied.     

Fate of Fertilizer Nitrogen Applied to Crops Grown on Fluvo-Aquic Soil in Huang-Huai-Hai Plain

The fate of urea-and ammonium bicarbonate(ABC)-nitrogen (N) applied by prevailing traditional techniques to winter wheat (Triticum aestivum L.)or maize (Zea mays L.)grown in the fields of Fluvo-aquic soil was investigated using ^15N tracer-micro-plot technique.Results show that:(1) at maturity of wheat,N recovery in plants and N losses of urea and ABC applied at seeding in autumn were 31-39%,and 34-46%,respextively,while the corresponding figures for side-banding at 10 cm depth in early spring were 51-57%,and 5-12%;surface-broadcast of urea followed by irrigation at early spring was as efficient as the side-banding in improving N recovery in plants and reducing N loss,however,such techuique was found less satisfactory with ABC.(2)At the maturity of maize,N recovery in the plants and N loss of urea and ABC sidebanded at seedling stage or prior to tasseling ranged from 23% to 57%,and 9% to 26%,respectively.(3) Either in Wheat or in maize experiment,the majority of residual fertilizer N in soil profile (0-60cm) was in the form of biologically immobilized organic N,however,the contribution of ammonium fixation by clay minerals increased markedly nwith depth in soil profile.(4) Though the proportion of residual fertilizer N was generally highest in the top 20 cm soil layer,considerable reaidual N (nostly 6-11% of the N applied)was found in 60-100 cm soil layers.     

太湖地区不同土壤-森林生态系统中林木生长对微量元素的反应及反馈效应

Vector analysis technique and ecological sequential comparison methods were adopted to study tree growth response to the micronutrients,B,Mo,Cu,Zn,Fe,and Mn,in soils derived from various parent materials in the forest area of Tailhu Lake region in southeast China,The results showed that the dry weight of individual current-year needle of Chinese fir(Cunninghamia lanceolata) grown on the soil derived from granite parent rock was increased by 8% and 13% in comparison with that grown on the soils derived from sandstone and ash-tuff parent rock,respectively.And such dry weight of loblolly pine (Pinus taeda) grown on the soil derived from sandstone parent rock was increased by 21% in comparison with that on the soil derived from ash-tuff parent rock.One of the reasons for those results was that micronutrients content in the soil derived from ash-tuff parent rock were not sufficient to meet the requirement of the growth of Chinese fir and loblolly pine ,i.e.,micronutrients in soil were deficient and/or induced defiient.The amounts of Cu,Zn,Fe,and Mn uptake by Chinses fir and loblolly pine were in agreement with the contents of available micronutrients in soil respectively,except for B and Mo.Meanwhile,there might exist and “antagonism“ between the uptake of B versus Mo by trees,although more studies are needed to confirm it .Regression analysis indicated that amount of a soil available micronutrient was correlated to the type of parent material and its total amount in the forest floor, except for B.The F test identified that the correlation of each equation reached the significant level to different extents,respectively,The t test confirmed that amount of available forms was mainly depended on the type of parent material for Mo,Cu,Zn and Mn but on the forest floor for ,Fe,There was a feedback effect of forest stand on the amount of soil available micronutrients.The ability of accumulating available micronutrients in soil was better by the sawtooth oak(Quercus acutissima) stand than by the Chinese fir stand (except for B).The ability of accumulating available Zn,Fe,Mn and Mo in soil was better by the Chinese fir stand than by the loblolly pine stand ,while as for available B and Cu,by the latter was better than by the former,When discussing the efect of forest stand on the amount of soil available micronutrients,not only the amount of micronutrient in the forest floor and the parent materials but also the amount of micronutrient taken up by current-year needles have to be considered.     

一株敌敌畏降解菌DDV-1(Ochrobactrium sp.)的分离鉴定及其降解特性的研究

Soil organic carbon （C） and total nitrogen （N） pools of a Chinese fir （Cunninghamia lanceolata （Lamb.） Hook.） （CF） forest, and an evergreen broadleaf （EB） forest located in mid-subtropical, southeastern China, were compared before clearcutting, with the effect of slash burning on organic C and total N in the top 10 cm of soil before and after burning also being evaluated. Prior to clearcutting CF forest had significantly lower （P 〈0.05） organic C and total N in the soil （0-100 cm） compared to EB forest with approximately 60% of the C and N at the two forest sites stored at the 0 to 40 cm soil. In post-burn samples of the 0-10 cm depth at 5 days, 1 year, and 5 years for CF and EB forests, significantly lower levels （P 〈0.05） of organic C and total N than those in the pre-burn samples were observed. Compared to the pre-burn levels, at post-burn year 5, surface soil organic C storage was only 85% in CF forest and 72% in EB forest, while total N storage was 77% for CF forest and 73% for EB forest. Slash burning caused marked long-term changes in surface soil C and N in the two forest types.     

pH对针铁矿表面磷酸盐吸附的化学形态的影响

Chemical forms of the phosphate adsorbed on goethite surfaces and characteristics of the coordinate groups which exchange with P on goethite surfaces in solutions with different pll values were investigated.Results showed that the chemical forms of P on goethite surfaces changed from the dominance of monodentate corrdination to that of bidentate one with increasing pH of the solution.By influencing types of phosphate ions in solutions,pH affected the chemical forms of P on goethite surfaces,The amount of OH^- displaced by phosphae on goethite surfaces was the most at pH 7.0,the second at pH 9.0,and the least at pH 4.5.     

根－土界面区域磷酸盐的分布和移动: Ⅱ. 土壤水分含量和磷酸盐施用量的影响

The phosphate in the soil-root interface zone under various soil water contents and application rates of phosphate was still of depletion distribution which could be described by a power function in the form of C/Co= ax^b(C/Co is the relative content of fertilized phosphate in a distance from the root surface x, a and b are the regression constants). The depletion rate of phosphate in soil near the root surface was higher and the depletion range was narrower under lower soil moisture. On the contrary, at higher soil water content the depletion range was wider, generally. The application rate of phosphate led to the greater depletion intensity of phosphorus was higher in the heavier texture soils. In general, the depletion intensity in the soils, which decreased with increasing clay content or increasing buffering power of soil, decreased in the order as loessal soil and black lou soil > lou soil > yellow cinnamon soil when 50 or 100 mg of phosphorus were applied in the form of KH₂PO₄. This result indicated that the phosphate distribution and its movement in the soil-root interface zone closely related with the buffering capacity of soil.