矮砧果树为什么变矮

在果树矮化密植栽培中,有以下几种方法使果树变矮:①利用矮化砧或矮化中间砧;②采用紧凑型品种;③采用致矮的农业技术;④使用生长调节剂。现仅用矮化砧为例,分析一下矮砧果树变矮的原因: 什么是矮化砧木具有矮化作用的砧木,叫矮化砧。矮化砧具有比其接穗细胞渗透势低的生物学特性。由于细胞的渗透势与溶质浓度成反比,所以,矮化砧组织细胞渗透势低而细胞液浓度较高。通过嫁接后,将与其接穗细胞形成浓度的逆生理差。     

聚乙二醇(PEG6000)模拟干旱胁迫抑制矮沙冬青种子的萌发

本研究以新疆特有濒危保护植物矮沙冬青(A mmmopiptanthus nanus(M.Pop.)Cheng f.)的种子为材料,用不同渗透势浓度的聚乙二醇(PEG6000)模拟干旱胁迫,探讨干旱胁迫对矮沙冬青种子发芽率、平均发芽速度、胚轴和胚根长度及发芽指数、活力指数的影响.结果表明,不同浓度PEG胁迫处理均降低了种子的发芽率,延缓了矮沙冬青种子萌发进程;种子的发芽率、发芽指数和活力指数均随胁迫强度的增加呈明显下降趋势.当-1.20 MPa的PEG胁迫处理的种子在试验结束时仍未能萌发,表明-1.20 MPa是矮沙冬青种子萌发的临界水势.PEG模拟干旱胁迫中,当PEG处理为-0.2 MPa时,虽然最终发芽率与对照一样,但其胚根、胚轴的长度都比对照短,说明矮沙冬青胚根、胚轴的生长比发芽率对干旱胁迫更敏感.干旱胁迫可能是导致矮沙冬青种群天然更新能力弱的原因之一.本研究将为矮沙冬青种质资源的保护和种群的恢复提供科学依据.     

矮败蓝标型小麦不育系的选育与研究

利用蓝粒太谷核不育硬粒小麦89-2343[AABB 4D(MS2)/4E]与普通小麦7739-3(2n=42)杂交、回交所产生的蓝粒可育株与白粒矮败材料杂交、回交,育成了一份矮败蓝粒小麦.选用13份遗传背景不同的白粒普通小麦与之杂交、回交,育成了13份矮败蓝粒小麦.对后代的粒色和育性分离进行分析,蓝粒矮败不育株占22.1%,白粒非矮秆可育株占77.7%,表明蓝粒基因、Ms2和Rht10均位于附加染色体上,且连锁紧密;但不同轮回亲本,矮败蓝粒的传递率有差异,477A的传递率最高,接近50%.细胞学分析表明矮败蓝粒小麦仍为单体附加系;探讨了矮败蓝粒小麦在群体改良和杂种小麦生产中的应用.     

苹果砧木SH40 MdNCED1基因克隆与表达分析

9-顺式-环氧类胡萝卜素双加氧酶基因是脱落酸合成途径的关键基因。本试验通过RT-PCR结合RACE技术从苹果SH40(Malus domestica×Malus Honanensis)茎尖组织中克隆了1条NCED基因,命名为MdNCED1(GenBank登录号为KC816734)。该cDNA序列全长2179 bp,包含1个编码606个氨基酸的开放阅读框。氨基酸同源性分析表明,MdNCED1与已报道的其他植物物种的氨基酸序列具有63.7%~93.0%的相似性。构建MdNCED1基因的原核表达载体pDEST15-MdNCED1,转入大肠杆菌(DE3),用IPTG诱导。SDS-PAGE分析表明,MdNCED1基因在大肠杆菌中被诱导表达的蛋白质分子量与预期结果一致。荧光定量结果表明,MdNCED1基因在SH28、M26、SH40及其嫁接品种嘎啦的表达趋势均呈先上升后下降的趋势,同时与其矮生程度呈正相关。     

水稻新矮源的诱变、鉴定和遗传研究

利用γ射线处理显性矮秆粳稻品种KL908,获得3份遗传稳定的半矮秆突变材料1042-4、1042-13和1045-7.遗传分析表明,这3份材料的半矮秆性状遗传均受隐性单基因控制.其中,控制1042-4和1045-7半矮秆性状的基因与矮仔占的sd-1基因等位,而控制1042-13半矮秆性状的基因与矮仔占的sd-1和新桂矮的sd-g基因非等位.     

水稻品种矮梅早3号抗稻瘟病的遗传

水稻杂交组合(矮梅早3号×华矮837)的F_3株系接种菌株78-189(ZD_3)和83-182(ZD_1),应用累积分布曲线法进行了抗稻瘟遗传分析,结果表明:水稻品种矮梅早3号含有4个主效抗性基因P_i-A_1、P_i-A_2、P_i-A_3和P_i-A_4,其中P_i-a_4为隐性基因。P_i-A_1和P_i-A_2控制对菌株78-189(ZD_3)的高抗性,同时,P_i-A_2兼控M类型对菌株78-189(ZD_3)的抗性。P_i-A_3,控制对菌株83-182(ZD_1)的抗性。P_i-A_4控制M类型对菌株83-182(ZD_1)的抗性。水稻品种华矮837对以上两菌株不存在抗性基因。     

金丝矮陀陀植物中的二个新甾体生物碱甙

从金丝矮陀陀植物中得到了二个新甾体生物碱甙——矮陀陀甙A、B。经光谱分析,结构测定,分别为20α-二甲胺-3-O-β-D葡萄糖基-5α-孕甾烷醇和20α-二甲胺-3-O-β-D葡萄糖基-5(6)-孕甾烯醇。     

山东荣成天鹅湖矮大叶藻种群的生态特征

在山东荣成天鹅湖发现较大面积的矮大叶藻,因天鹅湖独特的地理位置和矮大叶藻的高生物量,可以作为山东沿海矮大叶藻的典型代表.2011年9月至2012年10月,对天鹅湖东岸矮大叶藻及其生境进行了周年调查,初步掌握了该种的分布情况及其生境的生态特征.结果表明:矮大叶藻床沉积物成分以砂(81％)和粉砂(14％)为主,沉积物C、N含量在冬季最高,C/N秋季最高;矮大叶藻的密度、高度和地上生物量与水温显著相关(P＜0.05),生长呈现明显的季节变化,8-9月生物量最大.叶片的C、N含量及C/N因生长季节的不同而存在一定差异,C含量秋季显著高于春、夏季,N含量夏季显著低于春、秋季(P＜0.01),C/N夏季显著高于春季(P＜0.05).经估算,天鹅湖矮大叶藻的年固碳能力为111.4 g C·m-2.     

粤北伞菌的两个新种

本文报道了作者1984-1985年在广东北部山区所采集有关伞菌类中的13个种, 其中新种2个, 即粗糙孢湿星伞Hygroa ter trachyspocus Bi sp.nov.和糊精质孢矮菇Chanacota detiioidespora Bi sp.nov.以及11个国内新记录。其中矮菇属Chamaeota(W.G.Smith)Earle, 微菇属Mycenella(Lange)Sing.与翼孢菌属Pterospora Metrod均为国内新记录属。     

超高产杂交稻剑叶衰老过程中PSII功能的变化

对田间自然条件下培矮64S/E32和对照汕优63的剑叶衰老过程中PSII光化学效率、光能耗散和叶黄素循环组分的动态变化进行了研究.结果表明,水稻剑叶衰老过程中PSⅡ光化学效率(F/Fm)、PSII量子产量(φPSII)、光化学猝灭系数(qP)和光合速率(Pn)均降低,但非辐射热耗散(NPQ)、叶黄素循环库和中午时的脱环氧化状态则升高.移栽后55-75 d两品种剑叶的φPSII和qP变化相近,此后培矮64S/E32比汕优63下降缓慢.在生育后期的衰老过程中培矮64S/E32剑叶的PSII功能比汕优63下降慢,并具有更高的光能利用效率.     

Investigation of the mechanism of temperature sensitivity of the electroreceptors of ampullae of lorenzini

In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980.     

Principles of organization and evolution of systems of regulation of functions

Evolution of living organisms is closely connected with evolution of structure of the system of regulations and its mechanisms. The functional ground of regulations is chemical signalization. As early as in unicellular organisms there is a set of signal mechanisms providing their life activity and orientation in space and time. Subsequent evolution of ways of chemical signalization followed the way of development of delivery pathways of chemical signal and development of mechanisms of its regulation. The mechanism of chemical regulation of the signal interaction is discussed by the example of the specialized system of transduction of signal from neuron to neuron, of effect of hormone on the epithelial cell and modulation of this effect. These mechanisms are considered as the most important ways of the fine and precise adaptation of chemical signalization underlying functioning of physiological systems and organs of the living organism