Characterization and identification of leaf morphology of <Emphasis Type="Italic">Populus deltoides</Emphasis> Bartr. clones

Leaves are of fundamental importance to plants, representing their facility to generate power and are the sensing units of plants towards the environment. An attempt was made to characterize and compare the variations of leaf morphology of various Populus deltoides Bartr. clones by studying the winter buds and other leaf parameters of fully developed leaves. To achieve these objectives, forty-three exotic and indigenous clones of P. deltoides Bartr. were evaluated for different parameters. On the basis of various morphological characteristics the results reveal that each clone has a distinct color pattern of leaves. Different colors observed in these clones varied from light green through green to dark green. Two distinct lengths of the leaf apex were found, i.e., short and long; as well both acuminate and acute apex types were found. Erratic distribution of serration of leaves was also found. In this study, the morphological traits of leaves provided discriminatory grounds for separating various populations of P. deltoides Bartr. clones. Winter bud studies indicate that different clones vary considerably with regard to shape, color, shape of leaf scars and exudation.     

Differences in chlorophyll fluorescence parameters and water content in heteromorphic leaves of <Emphasis Type="Italic">Populus euphratica</Emphasis> from Inner Mongolia,China

We studied three typical heteromorphic leaves of Populus euphratica trees growing in the Wuhai region of Inner Mongolia,China,i.e.,lanceolate,broad-ovate and dentate broad-ovate leaves and mainly focused on the changes in chlorophyll fluorescence parameters and free water and bound water content.The results show that the values of Fm(maximal fluorescence yield),Fv/Fm(maximum photochemical quantum yield of PSII) and Fv/F0(potential quantum efficiency of PSII) of lanceolate leaves were the least on young trees,while these parameters were the least on the ovate leaves of old trees.Compared with young trees,the free water content of heteromorphic leaves of old trees increased significantly,i.e.,by 78.94% in lanceolate leaves and in the leaves of broad-ovate and dentate broad-ovate by 10.99% and 10.60%,respectively.Correlation analysis showed that free water content is significantly related to Fv/Fm and Fv/F0 in young trees,while the relationship of total water content with Fv/Fm and Fv/F0 is positive in old trees.     

橘红心娃娃菜新品种九千娃娃菜1号的选育

九千娃娃菜1号是山东春秋大白菜育种研究中心以自交不亲和系夏08-219与自交不亲和系08-371配制而成的橘红心娃娃菜杂交种。该品种生育期50～55d,矮桩合抱舒心炮弹型,类胡萝卜素含量55.7mg·kg-1,单球质量0.32～2.1kg,做娃娃菜栽培667m2可种植0.8万～1.2万株,做大白菜栽培时4000株左右。抗病毒病、霜霉病、软腐病、干烧心等多种病害,适宜全国大部分地区晚春、夏秋季栽培。     

Nutrient composition and short-term release from <Emphasis Type="Italic">Croton macrostachyus</Emphasis> Del. and <Emphasis Type="Italic">Millettia ferruginea</Emphasis> (Hochst.) Baker leaves

A field study was conducted to investigate the nutrient content of green and abscised leaves of Croton macrostachyus Del. and Millettia ferruginea (Hochst.) Baker and their decomposition to return these nutrients to the soil in the short-term. Green and abscised leaves were collected from trees of comparable size in Wondo Genet, Ethiopia, and were incorporated into litterbags to decompose for a period of 12 weeks. Green leaves of C. macrostachyus had significantly higher nutrient concentrations than those of M. ferruginea. In both species, green leaves had significantly higher (P<0.05) C, N and P and significantly lower (P<0.05) lignin and polyphenol concentrations than abscised leaves. Fifty percent of the biomass applied was lost during the first 7 weeks in C. macrostachyus, which was about 3 times faster than that of M. ferruginea. The half-lives of N and P were 5–8 weeks and 4–6 weeks, respectively, in C. macrostachyus; the corresponding values for M. ferruginea were 6–8 and about 22 weeks, respectively. Only 15.7% and 26.8% of green and abscised leaves of C. macrostachyus, respectively, were recovered after the 12 weeks of decomposition. The corresponding values were about 3.5-fold and 2.5-fold higher for M. ferruginea. Generally, leaves with higher initial lignin, polyphenol, lignin:N and C:N ratios had lower decomposition and mineralization rates. In both species, removal of leaf biomass before abscission (e.g. by pruning) could enhance both the quantity and rate of nutrient return to the soil.     

DNA分子标记在银杏中的应用

DNA分子标记广泛用于生物研究的许多方面。本文简要介绍了RFLP、RAPD、AFLP、SSR及ISSR等几种目前常用分子标记的原理,归纳总结了分子标记在银杏中的应用研究进展。(1)获得了2个雄性特有的RAPD标记和2个雌性特有的AFLP标记,为银杏的早期性别鉴定及相关基因克隆奠定了基础;(2)采用RAPD标记和ISSR标记对我国部分栽培品种进行了分子鉴别和分类的研究,编制了一些品种的DNA指纹检索表;(3)利用RAPD和ISSR标记对一些群体、个体及栽培品种或变异类型进行了遗传分化和遗传多样性研究,结果发现银杏具有较高的遗传多样性,群体间、个体间、栽培品种及类型间都存在不同程度的遗传分化;(4)利用ISSR标记对一些个体的遗传杂合性进行了研究,结果显示个体的平均杂合率为43.53%;(5)构建了包含62个RAPD标记、19个连锁群的银杏分子遗传图谱;(6)探索了银杏优先保护种群的确定。分子标记在银杏其它方面的应用还很少。今后,除了继续对上述方面进行深入系统的研究外,还应充分运用DNA分子标记技术,开展银杏的分子标记辅助选择育种、种质评价与鉴别及保育生物学等方面的研究。     

不同时期四倍体刺槐叶片氨基酸营养及其生物量初步分析

测定了廊坊地区饲料型四倍体刺槐叶粉4个不同时期的粗蛋白质含量及18种氨基酸组分,用氨基酸分(AAS)和必需氨基酸指数(EAAI)对其氨基酸营养进行评价,并结合其生物量对最佳刈割时期进行了分析。结果表明,饲料型四倍体刺槐叶粉4个时期的粗蛋白1、8种氨基酸总量和12种必需氨基酸含量均较高,且呈现随时间的推移而逐渐下降的趋势;其必需氨基酸分(AAS)均较高,氨基酸组成较平衡;对牛、猪、鸡、鸭、鹅、草鱼、对虾和羊8种动物的必需氨基酸指数(EAAI)4个时期之间无差异,均大于0.86,可作为这些动物的优良植物饲料蛋白源;在7月中下旬其生物量和营养达到了最佳结合点,适宜采摘或刈割。     

樟树叶片抑菌化合物的分离纯化及其部分特性研究

以碱提取、酸沉淀的方法从樟树叶片中分离得到一种棕黑色粉末，该提取物主要为有色化合物Ａ和Ｂ的混合物，化合物Ａ的含量成倍高于化合物Ｂ；经ｓｉｌｉｃａｇｅｌ、Ａｌ＿２Ｏ＿３及ｓｅｐｈａｄｅｘＧ－２５柱层析分离纯化等步骤，得到纯化的红棕色化合物Ａ，经ＰＡＧＥ、ＰＬＣ及ＴＬＣ检测均为单一谱带或单一斑点；该化合物熔点为２８０．２９℃，λ＿（ｍａｘ）￣（ＫＯＨ）为２１３ｎｍ，Ｅ１ｃｍ１％为３４２．５，肩峰为２５７ｎｍ，ｐＩ为３．７，对大肠杆菌、金黄葡萄球菌、巨大芽孢杆菌、枯草杆菌及毛霉有较强的抑菌活性。     

Decomposition of leguminous crop residues in a ‘jhum’ cultivation system in Arunachal Pradesh,India

Decomposition of leaves, stems, and roots of two leguminous plants, french bean and pea, was studied in a ‘jhum’ cultivation (shifting agriculture) system in north‐eastern India in litter bag experiments. The dynamics of decomposition varied between the crop residues and species studied. All the three studied types of residues of french bean and the leaves and roots of pea showed polynomial decomposition model with three distinct phases: an initial slow decomposition phase (1), followed by a faster decomposition rate (2) and again by a slow decomposition phase (3). However, the stems of pea plants showed an exponential increase in the decomposition rate during field incubation. Initial N, lignin, and lignin : N ratio were determined in crop residues. In general, roots decomposed slowly as compared to the leaves and stems due to greater lignin content. Soil microbial activity as determined by CO₂ evolution was significantly correlated with the decomposition rates. Over all, the decay constants reveal that these fast decomposing leguminous crop residues can be properly managed for soil nutrient management in the low input shifting agricultural fields in the hills.     

冻存茶鲜叶多酚氧化酶动力学特性研究

采用分光光度法对冻存处理的茶树鲜叶的多酚氧化酶(PPO)进行了活性测定,研究了底物浓度、pH值及温度对冻存茶鲜叶PPO活性的影响,建立了茶树鲜叶冻存-萎凋过程的反应动力学方程.结果表明,冻存茶鲜叶PPO酶活的最适条件为:pH值介于4.6～5.0之间,温度35～60℃.由Michelis-Menten方程1/v=1.16...