Taxonomy, Geographic Distribution and Ecological Habitats of Tree Peonies

Tree peonies belong to Paeonia L. section Moutan DC., Paeoniaceae. All wild tree peonies are endemic to China, which is also the first domestication place of cultivated tree peonies. A new taxonomic system of Sect. Moutan was proposed by Hong and Pan (Hong D.Y. and Pan K.Y. 1999a. Acta Phytotax. Sin. 37: 351–368; 1999b). In their system eight species, of which three each has two subspecies are recognized. Wild tree peonies are distributed in Henan, Gansu, Shaanxi, Shanxi, Anhui, Hubei, Sichuan, Yunnan and Xizang (Tibet) of China. The most densely populated area is Henan province, where five wild species (subspecies) are found and supposed to be related to the origin of cultivated tree peonies. Since 1990 considerable work on taxonomy of tree peonies has been done by Chinese botanists, which is summarized in this paper. In addition, the nomenclature history of the tree peony species listed in Hong and Pan's (Hong D.Y. and Pan K.Y. 1999a. Acta Phytotax. Sin. 37: 351–368; 1999b) system is reviewed and the information on their geographical distribution and ecological habitats is presented.     

岷江上游油松与华山松人工混交林对降雨的截留分配效应

人工油松与华山松混交林是岷江上游区域主要的群落类型，采用水量平衡的方法，研究了混交林林冠截留量、穿透量、树干茎流量等指标。通过混交林对24场降雨分配的定位观测，结果表明林冠截留量83．47mm、穿透量81．43mm、茎流量2．00mm，分别占同期降雨量的50．o％，48．8％，1．2％；幂函数方程能较好地拟合林冠截留量与林外降雨量之间的关系，而线性方程能较好地拟合穿透雨量、树干茎流量和林外降雨量之间的关系。结果表明恢复重建后的人工油松与华山松混交林生态系统在水源涵养、水土保持上效果明显。     

紫色土K+吸附解吸动力学研究

从国家紫色土肥力与肥料效益监测基地定位试验上 ,在第 10年水稻收获后从 0～ 30cm土层采取土壤样品 ,研究土壤K 吸附、解吸动力学过程。结果表明 ,不同施肥处理土壤K 吸附、解吸反应分别在2 4～ 32min和 4 6～ 6 4min达到平衡 ,吸附、解吸平衡量分别为 14 1～ 19 2cmolkg-1和 11 6～ 17 5cmolkg-1。相关分析说明 ,土壤阳离子交换量 (CEC)及粘粒含量是影响吸附平衡时间、吸附平衡量的重要因素 ;CEC、交换钾量是影响解吸平衡时间、解吸平衡量的重要因素。由此可见 ,长期不同施肥对土壤CEC、粘粒及交换钾量产生影响 ,从而影响了紫色土K 吸附、解吸平衡时间及吸附、解吸平衡量。平衡前钾离子的吸附、解吸速度及吸附、解吸率与反应时间lnt间存在良好的线性关系。其中反应速度直线和解吸率直线的斜率、初始反应速度及初始吸附率均与CEC、粘粒含量密切相关。Elovich方程和一级扩散方程分别为描述紫色土K 吸附、解吸反应的最优与最差模型 ,指数方程和抛物线扩散方程拟合性介于Elovich方程和一级扩散方程之间。由此可见 ,紫色土K 吸附、解吸过程不是一个单纯的过程 ,而是一个包括土体膨胀、吸附位活化、表面扩散等诸多因素的复杂过程。     

Soil microbiological and biochemical properties affected by plant growth and different long-term fertilisation

The purpose of this study was to measure the effects of plant growth on soil microbial biomass C (C_mic) and soil enzyme activities. In a pot experiment using spring barley and sugar beet, we investigated the response of C_mic, hot water extractable C and N fractions (C_hwe, N_hwe), and enzyme activities involved in C, N and P cycling in a loess-derived Chernozem from Bad Lauchstädt (Central Germany). The study site has been receiving the same fertilisation treatments for 100 years. The soil originated from plots fertilised with 15 t ha⁻¹ farmyard manure (FYM) year⁻¹ + mineral fertiliser (NPK), or 15 t ha⁻¹ FYM year⁻¹, or NPK or from an unfertilised control. Pots were sampled monthly, and alkaline phosphatase- (AP), β-glucosidase- and protease-activities were analysed. At the beginning and the end of study, levels of C_mic, C_hwe and N_hwe were also measured. All three enzyme activities and C_mic were significantly and positively correlated with C_org and C_hwe. Results suggest that the enzyme activities measured originated mostly from microorganisms and that C_hwe is an important C source for soil microorganisms. β-Glucosidase and AP activities were higher in summer months than at other times. In contrast, protease activity changed only slightly during the growing period.     

氮钾配施对不同品种莴笋光合特性的影响

通过盆栽试验研究了不同光照强度下氮钾配比对3个品种莴笋光合特性的影响。结果表明,增施氮钾肥3个莴笋的光合速率增加,光合速率Pn随光照的增加而增加,双尖的Pn最低,大白甲和挂丝红的Pn较高。不同施肥处理对双尖光合特性影响较小,在低、中、高光照下对挂丝红光合特性正效应较大的处理分别为N15K15、N20K10、N20K10,而N20K10、N15K15、N15K15处理对3个品种光照下大白甲光合特性正效应较大,高氮配施叶类蔬菜硝酸盐复合控制剂处理使低、高光照下大白甲的Pn、Gs、Ci和Tr提高,而中光照下对上述4个光合特性指标影响不大。不同光照下氮钾对莴笋光合特性的影响随莴笋品种的不同而异。     

白细胞介素12的研究概况与进展

白细胞介素12因其独特的生物学功能自发现以来就成为研究热点。它能够通过刺激NK细胞活化、增殖及产生IFN-γ而改变Th1/Th2平衡向Th1方向发展,在细胞介导的免疫中发挥了重要作用,因此在抗肿瘤、抗病毒、抗寄生虫等方面有广阔的应用前景,并成为一种良好的疫苗免疫佐剂。     

重庆地区致病疫霉(Phytophthora infestans)交配型测定

通过对峙培养在RSA和RTA上对重庆地区主要马铃薯和番茄产区的致病疫霉交配型进行了测定。结果显示,分离自重庆地区8个县(区)的186个致病疫霉菌株均为A1交配型,没有检测到A2交配型。这一结果表明该地区的致病疫霉仍以A1交配型为主。     

夏橙绿斑病的病原鉴定及其生长特性研究

夏橙绿斑病是一种新报道的病害。通过对病原进行分离鉴定和生长特性研究,表明该病是由绿藻门虚幻球藻属虚幻球藻(Apatococcuslobatus)所致;病藻的适应温度范围比较广,5￣30℃都可生长,15￣25℃为其适温范围;病藻具有广泛的光适应性,在500￣4000lx的光照范围内均可生长,1000￣3000lx为其适宜的光照范围;在pH值为4￣10时病藻均能生长,适宜生长的pH值为5￣9。田间观察结果表明,该病的发生还与空气湿度密切相关,当空气湿度大于80%时,发病就严重。     

薄壳山核桃优质砧木的培育技术

为了缩短薄壳山核桃砧木的出圃时间,提高其嫁接成活率,就薄壳山核桃大颗粒种子与小颗粒种子、种子的不同贮藏方法、不同胚根尖与容器处理、不同截根处理与施肥浓度对1年生薄壳山核桃实生苗的高度与地径生长的影响情况进行了对比试验.结果表明:种子大小对苗木的地径和高度均有较大的影响,在育苗过程中,应优先选择颗粒饱满的大粒种子进行育苗...     

苦瓜的研究进展及展望

综述了我国苦瓜栽培、育种、制种技术的研究进展,并对未来苦瓜的研究方向进行了展望.