DIFFERENTIAL RESPONSES OF PLANT FOLIAGE TO SIMULATED ACID RAIN

Experiments were performed to show the responses of foliage of several clones of Tradescantia sp., Pteridium aquilinum, Quercus palustris, and Glycine max to simulated acid rain. These experiments were performed to (a) predict the relative sensitivities of foliage of these plants to acid rain, and (b) identify leaf surface and anatomical alterations to simulated acid rain that may be used to diagnose acid rain injury. Plants were exposed to simulated rain at pH levels of 5.7, 3.4, 3.1, 2.9, 2.7, 2.5, and 2.3. Sporophyte leaves of bracken fern {P. aquilinum) were most sensitive to simulated acid rain among the species tested. About 10% of the surface area of older leaves of P. aquilinum was injured after exposure to 10 rainfalls at pH 2.5 (a single 20-min rainfall daily). Foliage of pin oak (Q. palustris) exhibited less than one-percent leaf area injury after exposure to simulated rain at pH 2.5 after 10 rainfalls (one 20-min rainfall daily). The responses of soybeans (G. max) and spiderwort (Tradescantia sp.) were intermediate between these two extremes. Histological observations show that lesion development results in collapsed leaf tissue in all four species. Gall formation that resulted from both cell hypertrophy and hyperplasia occurred in lesions of Tradescantia, and Q. palustris. Limited hyperplastic and hypertrophic reactions occurred in G. max foliage after exposure to simulated acid rain but no leaf galls resulted. Sporophyte foliage of P. aquilinum exhibited a “granular” type abnormality in the cytoplasm prior to the collapse of some epidermal cells injured by simulated rain. Injury occurred most frequently near vascular tissues and trichomes in all four species. In general, plant species that show cell hyperplasia and hypertrophy of leaf tissues after exposure to simulated acid rain are injured less than species that do not show these responses.     

THE MEAN INNER RADIUS OF SUN AND SHADE ILEX OPACA LEAVES

The mean inner radius of thickness M, a shape measure defined as the mean of the shortest distances d to the border from all internal points P_i of an object, was applied in its dimensionless form D₀M to Ilex opaca sun and shade leaves. This measure has the following attributes: 1) ubiquitous input; 2) the point function f(P) = d is always single valued; 3) it is an intrinsic measure; 4) it is nondirectional; 5) the same definition may be used for any dimension number and be extended to other functions of d. Since Ilex opaca is found in hot, sunny environments, one might predict its sun leaves to be smaller in area and “narrower” in shape (lower D₀M) than shade leaves, making them better convective coolers. Although sun leaves of Ilex opaca have been shown to be smaller in area, their D₀M was unexpectedly greater than shade leaves.     

不同发育年龄大鼠肝细胞及其溶酶体对急性低氧的应答

人工低压舱内模拟高原低氧24h,并与2300m对照组比较,观察不同发育年龄大鼠SGOT活力,肝溶酶体总酸性磷酸酶、非沉淀酸性磷酸酶和芳基硫酸酯酶活力及肝重、肝细胞糖原、蛋白和总脂含量的变化。在海拔5000m高度,10天鼠各酶活力、570天鼠总酸性磷酸酶和芳基硫酸酯酶活力明显升高;35和75天鼠各酶活力未见显著变化;在海拔8000m高度,各年龄组鼠上述各酶活力均显著升高。随着海拔高度的升高,各组大鼠肝重呈不同程度的下降,肝细胞糖原含量非常明显地减少,35和75天鼠8000m组全肝蛋白含量下降明显,10、35、75天鼠肝细胞总脂累积。上述结果综合分析表明:低氧致使大鼠肝细胞损伤属一普遍性效应,新生期和老年期大鼠肝细胞耐低氧能力不及幼年期和成年期大鼠。     

OLFACTORY RESPONSES OF LYSIPHLEBIA JAPONICA TO VOLATILE CHEMICALS AND FRESH LEAVES OF THE HOST PLANTS OF COTTON APHIDS IN OLFACTOMETER

Abstract The behavioral responses of the female adult parasitoids Lysiphlebia japonica to plant volatile chemicals, host plants and cotton aphids were tested in a four arm air flow olfactometer. The results indicated that the female parasitoids were strongly attracted by the odors from cotton aphids and their host plants. Damaged cotton leaves were more attractive than intact ones. Among the four olfactory stimuli from the plant volatile chemicals dissolved in liquid paraffin oil at the concentration of 0.01 (volume fraction), the female parasitoids only positively responded to benzaldehyde, but did not show any preference to β-caryophyllene and β-pinene. Although heptanol elicited the highest EAC response of the parasitoids, the behavioral test showed that it repelled the parasitoids, and β-pinene shared the same feature with heptanol at the concentration of 1 (volume fraction). Our results also showed that the female parasitoids only preferred the cotton leaf from which the mummified aphids were collected, and did not express any interest to the three plants of melon family in the olfactometer, The possible mechanisms are discussed.     

棉蚜茧蜂对某些挥发性次生化合物及棉蚜寄生植物的嗅觉反应(英)

本文利用四臂嗅觉计测定了雌性棉蚜茧蜂Lysiphlebia japonica对棉蚜四种寄主植物新鲜叶片、棉蚜和几种挥发性次生化合物的嗅觉反应,结果表明新鲜棉叶片和棉蚜的气味对棉蚜茧蜂有强烈的吸引作用,两者相混合使吸引作用明显增强;切碎的叶片比未切碎的叶片更具吸引作用。所测试的四种挥发性物质β-caryophyllene、heptanol、benzaldehyde和β-pinene,在浓度为0.01(体积分数)时,只有benzaldebyde对棉蚜茧蜂具有吸引作用,β-caryopbyllene和β-pinene对棉蚜茧蜂的吸引作用不明显,而heptanol对该蜂具有排斥作用。β-pinene在浓度为1(体积分数)时,也对该蜂具有排斥作用。对于棉蚜的四种寄主植物棉花、黄瓜、南瓜和丝瓜的完整叶片,棉蚜茧蜂只对棉花叶片产生定向反应,而对其它三种瓜类叶片没有反应。根据上述结果可以推知嗅觉在寄生蜂的寄主寻找过程中起着重要作用,绿叶气味物质和寄主气味可能是寄生蜂寻找寄主的远距离化学线索。棉蚜茧蜂对寄主定向是识别了特定化学指纹图谱,单一的某种化合物在寄主定向过程中所起的作用并不象预测的那样重要,而且组成图谱的物质并不是简单地混合在一起,而是相互作用,或加强或抑制。羽化前经历能够对寄生蜂的行为产生较大影响。     

两种挺水植物对水位变化的生长响应

水文情势是湿地生态系统最重要的环境因素之一,对土壤环境、物种分布及植被组成具有决定作用,长时间水淹可导致大量物种死亡,改变植被组成和结构。水文情势主要包括两个方面:水位(淹水深度、频率和持续时间等)和水质,二者都会对植被产生显著影响。湿地植物的生长、繁殖和生物量分配等在受水位的影响时表现出一定差异,且物种之间表现不一致;当高水位持续时间超过30d时,物种存活率会显著降低;而较低的水位波动     

THE ANATOMIC RESPONSES OF DAUCUS CAROTA TO THE ASTER YELLOWS VIRUS

Struckmeyer, B. Esther. (U. Wisconsin, Madison.) The anatomic responses of Daucus carota to the aster yellows virus. Amer. Jour. Bot. 50(9): 959–963. Ilus. 1963.—The leaves, petioles, and roots of carrots (Daucus carota) displaying aster yellows virus in the field and those infected with the aster yellows virus inoculated by the 6-spotted leafhopper were examined anatomically. Compared to the uninoculated, the young infected leaves displayed fewer layers of palisade cells and larger spongy parenchyma cells with a more compact arrangement. Mature leaves of infected plants sometimes were undulated and had few chloroplasts, many of which appeared fragmented. Hypertrophy and hyperplasia in the phloem tissue were associated with some necrosis and obliteration of cells. Long, needle-shaped crystalline inclusion bodies were present in the phloem in the leaves and roots. Most of the vascular bundles of the petiole were abnormal. Malformations included proliferating phloem cells, which in some instances almost encircled the bundle, hyperplasia of the phloem, hypertrophy of the parenchyma, and considerable necrosis and obliteration of these cells. Other responses included the division into 3 or 4 rows of the large outer phloem parenchyma by parallel walls so that a cambium-like layer was simulated. The tissue enclosed by this layer divided and underwent considerable necrosis and gummosis. Lacunae were found between the phloem bundle cap and the older phloem. Some of the cells in the phloem tissue differentiated into bundles with xylem. Numerous, short, lateral roots were conspicuous on the main root. The most noticeable response of the root tissue to this malady was hyperplasia and hypertrophy of the phloem followed by cellular disorganization, necrosis, and obliteration of cells. Some sieve tubes, companion cells, and parenchyma contained a gumlike deposit.     

ADAPTIVE RESPONSES OF PREDATORS TO PREY AND PREY TO PREDATORS: THE FAILURE OF THE ARMS-RACE ANALOGY

This paper analyzes a number of relatively general models of predator-prey adaptation and coadaptation. The motivation behind this work is, in part, to evaluate the “race analogy” that has been applied in analyzing predator-prey coevolution. The models are based on the assumption that increased investment in predation-related adaptations must be paid for by decreased adaptation to some other factor. Increased investment in predation-related adaptations by the prey lowers the predator's functional response, and increased investment by the predator increases the functional response. The models are used to determine how each species should respond to an increase in the predation-related investment of the other species. Several broad classes of population-dynamics models and several alternatives for the cost of predation-related adaptation are investigated. The results do not support the general applicability of the race analogy. In the type of model analyzed in greatest detail here, predator and prey adaptations combine multiplicatively in determining the predator's capture-rate constant. In such models, prey usually increase investment in predator avoidance or escape when predators increase their investment in capture. However, predators often do not change or decrease their investment in response to an increase in the prey's investment. The direction of the predator's response depends on the particular parameter that pays the cost of increased predation investment, the shape of the cost-benefit functions, and the assumptions about the population dynamics of the predator-prey system. Similar models are used to determine whether increased investment by one species should increase the rate of incorporation of mutations that improve the predation-related adaptations of the other species. The arms-race analogy also fails for this case. The results cast doubt on the usefulness of Dawkins and Krebs (1979) “life-dinner” principle.