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。     

三种苔藓植物对模拟N沉降的生理响应

该文研究了华南地区常见的3种苔藓植物大灰藓(Hypnum plumaeforme)、刺边小金发藓拟刺亚种(Pogonatum cirratum subsp. fuscatum)和石地钱(Reboulia hemisphaerica)在模拟N沉降条件下碳氮代谢的响应特征, 探讨了N沉降对这3种苔藓植物生长的影响。结果表明: 3种植物对N沉降的响应存在差异。大灰藓在加氮浓度为0 ~ 60 kg N·hm^-2的范围内, 光合速率、淀粉、可溶性糖、总氮及可溶性蛋白的含量均随加氮浓度的升高而上升; 对照条件下NR(硝酸还原酶)可诱导活性很高, 表明其对氮的需求强烈; 膜K⁺渗漏在加氮浓度为20 kg N·hm^-2时高于对照, 但更高的加氮浓度下并未使其进一步上升。刺边小金发藓拟刺亚种在加氮浓度为0~40 kg N·hm^-2的范围内, 碳氮代谢的多数指标的变化趋势与大灰藓相似, 但当N沉降高于40 kg N·hm^-2时, 呈现相反的变化趋势; 在对照条件下具一定的NR可诱导活性, 但人工加氮使其可诱导活性急剧下降。石地钱的可溶性糖及可溶性蛋白含量在不同处理条件下变化不明显, 但光合速率和淀粉含量在加氮浓度为20和40 kg N·hm^-2时低于对照及加氮浓度为60 kg N·hm^-2时, 而植物总氮含量的变化趋势刚好相反; NR固有活性及可诱导活性在各种N处理条件下均极低, 显示其对NO₃^-利用率低。刺边小金发藓拟刺亚种和石地钱的膜K⁺渗漏仅在60 kg N·hm^-2处理时显著上升。     

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。     

模拟酸雨对杜仲叶氮代谢的影响

 探讨了春夏两季模拟酸雨对杜仲(Eucommia ulmoides Oliv.)叶氮代谢的几个关键酶及相关物质含量的影响。结果表明：春夏两季杜仲叶硝酸还原酶(NR)、谷酰胺合成酶(GS)、谷氨酸脱氢酶(GDH)和谷丙转氨酶(GPT)活性在一定pH值酸雨胁迫下随酸雨pH值的降低而降低,夏季各酶活性下降率比春季高。杜仲叶可溶性蛋白质和总氮含量春夏两季也随酸雨pH值降低而降低(夏季可溶性蛋白含量与pH值呈正相关),总游离氨基酸含量则随pH值的降低而升高(二者呈负相关)。由此可见,酸雨对杜仲叶氮代谢产生了显著影响。     

大豆光合速率和气孔导度对水分胁迫的响应

土壤水分胁迫使两个供试大豆品种(系)光合速率和气孔导度降低,“鲁豆四号”降低的幅度大于小粒大豆品系“7605”。在相同的叶水势下,“7605”的光合速率和气孔导度均高于“鲁豆四号”,但“7605”气孔随水势下降而关闭的速率大于“鲁豆四号”。水分胁迫使叶片温度升高,“7605”比“鲁豆四号”升温较快,但在同一水分处理中,“鲁豆四号”的叶温高于“7605”。水分胁迫降低了大豆的水分利用效率,且“鲁豆四号”降低的速率大于“7605”。结果表明,“7605”对水分胁迫具有较好的适应能力。     

亚热带常绿阔叶林下富贵草 （Pachysandra Terminalis）对模拟光斑的光合响应（英文）

 以亚热带常绿阔叶林下一种常见的灌木富贵草(Pachysandra terminalis）为研究对象,利用气体交换和叶绿素荧光技术研究了其对模拟光斑的光合响应。在同样辐射通量（非光抑制）的情况下,光合诱导过程的快速组分时间内光斑可以提高富贵草对光斑的利用能力（光斑诱导的碳同化量可高出对照48%）。叶绿素荧光测量结果表明：1）光斑与光斑之间的暗期发生了qN弛豫过程;2）暗期之后的光期光化学能量转换效率提高。这两个原因可能是快速组分时间内光斑诱导富贵草的碳同化量提高的主要原因之一。强光光斑簇可以诱导富贵草光抑制     

THE STIGMATIC PAPILLAE OF AMYEMA (LORANTHACEAE): DEVELOPMENTAL RESPONSES TO PROTANDRY AND SURFACE ADAPTATIONS FOR BIRD POLLINATION

The flowers of Amyema miquelii and A. miraculosum are protandrous and pollinated by birds. Their dry-type stigmatic surface is composed of unicellular papillae. At the male phase, these papillae are constricted with rugulose surfaces. During the transition to the female (pollen receptive) phase these cells expand, almost doubling in width while their surface becomes much smoother. Beneath the thin proteinaceous pellicle, the papillar wall consists of an extraordinarily thick bi-layered cuticle overlying the primary wall. The two layers of the cuticle are stained by lipid dyes, but are distinguished by their different responses to other cytochemical tests. The reaction product for the enzyme esterase is present within crenulations on the papillar surface in small amounts, and in dense deposits in the cuticular clefts at the base between papillae. Not surprisingly, pollen tubes are unable to penetrate the thick papillar cap and enter the style through these clefts. The unusual thickness of the cuticle is interpreted as an adaptive response to pollination by perching birds (passerines) probing for nectar.