TEMPERATURE CHARACTERISTICS FOR THE PRODUCTION OF CO2 BY GERMINATING SEEDS OF LUPINUS ALBUS AND ZEA MAYS

The rates of production of CO₂ by germinating seeds of Lupinus albus and Zea mays were studied between temperatures 12.5° and 25°C. with the HCl-Ba(OH)₂ titration method. The temperature characteristics found are different from those previously obtained for the oxygen consumption of the same seeds germinated in the same manner. For Lupinus, the temperature characteristics above and below the critical temperature of 20° are 16,100 ± and 24,000 ± calories respectively. For Zea, no evidence of a critical temperature was found in this region, and the temperature characteristic is 20,750 ± calories throughout the range of temperature tested. The possible interpretations of the difference in the values of temperature characteristics for oxygen consumption and for production of CO₂ are noted.     

TEMPERATURE CHARACTERISTIC FOR THE ANAEROBIC PRODUCTION OF CO2 BY GERMINATING SEEDS OF LUPINUS ALBUS

The rate of anaerobic production of CO₂ by germinating seeds of Lupinus albus was studied as a function of temperature between 7.5° and 18°C. The mean value for the temperature characteristic was found to be 21,500± calories, which is slightly lower than that for the same process under aerobic conditions (23,500± calories). The values for the individual µ''s in the two cases overlap considerably. The possible identity of the processes underlying the production of CO₂ aerobically and anaerobically is discussed.     

ON THE RESPIRATORY QUOTIENT OF LUPINUS ALBUS AS A FUNCTION OF TEMPERATURE

The temperature characteristics for the oxygen consumption and CO₂-production of the germinating seeds of Lupinus albus were previously found to be different. It was predicted qualitatively that the respiratory quotient of the seed should be a function of temperature. A quantitative treatment is presented here, relating the change of the respiratory quotient with temperature and the temperature characteristics. Experimental results agree satisfactorily with the calculated value.     

玉米根冠中类外连丝的结构特征及其共质传输功能(简报)

胞间连丝是植物体内连接两个相邻细胞原生质体的共质运输通道,在胞间物质的转运和通讯联络上发挥重要作用。胞间连丝的功能在生理上主要体现在它对胞间转运物质的通透性（permeability）,通透性的变化和调节影响到许多生理过程的进展与协调。在植物的不同组织及其发育的不同阶段,不同的物化因素,不同的逆境胁迫以及病原物的侵染均可导致胞间连丝的通透性呈现相应的变动。胞间连丝存在形式的多样性以及对其不同程度和不同方式的修饰,均可对胞间连丝的生理功能及其通透性有明显的影响。[第一段]     

FERTILIZATION AND THE TEMPERATURE COEFFICIENTS OF OXYGEN CONSUMPTION IN EGGS OF ARBACIA PUNCTULATA

The eggs of A. punctulata have a high temperature coefficient in the resting state: Q ₁₀ = 4.1. On fertilization and on cytolysis the temperature coefficient falls to less than half the resting value: Q ₁₀ = 1.8 and 1.9 respectively. The factor by which oxygen consumption increases on fertilization is a variable, its magnitude depending on temperature as well as on egg species. It is nearly ten times greater at 11°C. and only double at 29.9°C. By extrapolating to 32°C. there would be no increase on fertilization. Critical thermal increments common to many oxidations, 6,500, 10,800, and 12,500, have been found. The possible significance of these results is discussed in relation to the catalytic mechanisms and structural organization of the egg cell.     

聚群与环境温度对黄毛鼠耗氧量的影响

黄毛鼠(Rattus losea)是我国长江以南分布极广的一种农林业重要害兽,也是南方恙虫病立克次体及钩端螺旋体的主要贮存宿主之一。林浩然等(1961)对黄毛鼠的某些生态研究中发现,该鼠在广东地区,秋冬季常有数只成鼠(6—7)同穴群居习性。1979—1980年,我们在浙江北部对黄毛鼠的生态作四季调查时,也发现此鼠于冬季有集群现象。但由于对黄毛鼠的生理生态还研究得很少,例如环境温度对黄毛鼠的影响怎样?聚群有何生理生态学方面的意义?因此本文试图着重探讨一下聚群与环境温度对黄毛鼠的能量代谢影响。     

光对绿豆种子和叶片分离线粒体耗氧的影响

实验结果表明:照光时绿豆叶片分离线粒体通过细胞色素氧化酶途径的NADH氧化部分受阻,电子转向交替途径。不产生能量,不受能荷控制的NADH氧化途径有利于绿色细胞线粒体在光合作用时执行其提供碳架的功能。看来绿色细胞线粒体本身具有对光的敏感性,在照光时调节呼吸途径以适应其功能的转换。呼吸途径的转换机制目前还不清楚。绿豆种子线粒体与叶片线粒体不同,没有上述的这种对光的反应。     

ULTRASTRUCTURE OF THE LAMELLAE AND GRANA IN THE CHLOROPLASTS OF ZEA MAYS L

The fine structure of the chloroplasts of maize (Zea mays L.) has been investigated by electron microscopic examination of ultrathin sections of leaves fixed in buffered osmium tetroxide solutions. Both the parenchyma sheath and mesophyll chloroplasts contain a system of densely staining lamellae about 125 A thick immersed in a finely granular matrix material (the stroma), and are bounded by a thin limiting membrane which often appears as a double structure. In the parenchyma sheath chloroplasts, the lamellae usually extend the full width of the disc-shaped plastids, and grana are absent. The mesophyll chloroplasts, however, contain numerous grana of a fairly regular cylindrical form. These consist of highly ordered stacks of dense lamellae, the interlamellar spacing being ca. 125 A. The grana are interlinked by a system of lamellae (intergrana lamellae) which are on the average about one-half as numerous as the lamellae within the grana. In general, this appears to be due to a bifurcation of the lamellae at the periphery of the granum, but more complex interrelationships have been observed. The lamellae of the parenchyma sheath chloroplasts and those of both the grana and intergrana regions of the mesophyll chloroplasts exhibit a compound structure when oriented normally to the plane of the section. A central exceptionally dense line (ca. 35 A thick) designated the P zone is interposed between two less dense layers (the L zones, ca. 45 A thick), the outer borders of which are defined by thin dense lines (the C zones). Within the grana, the C zones, by virtue of their close apposition, give rise to thin dense intermediate lines (I zones) situated midway between adjacent P zones. A model of the lamellar structure is proposed in which mixed lipide layers (L zones) are linked to a protein layer (P zone) by non-polar interaction. Chlorophyll is distributed over the entire lamellar surface and held in the structure by van der Waals interaction of the phytol "tail" with the hydrocarbon moieties of the mixed lipide layers. The evidence in favour of the model is briefly discussed.