寄主植物对棉蚜羧酸酯酶活性的影响

不同棉花品种对棉蚜Aphis gossypii Glov.羧酸酯酶活性具有明显的影响,在试验的7个棉花品种中,取食中棉12叶片的棉蚜α-乙酸萘酯(α-NA)羧酸酯酶活性最高(2.47微摩尔/毫克蛋白质分钟),是取食泾阳鸡脚棉种群的5.74倍.β-乙酸萘酯(β-NA)羧酸酯酶的活性以取食方渑双无的棉蚜最高(3.41微摩尔/毫克蛋白质分钟),是取食BR-S-10棉蚜的4.49倍.在取食方渑双无叶片的棉蚜中,羧酸酯酶活性大于2.5(微摩尔/毫克蛋白质分钟)的个体占28.3%(α-NA)和67.1%(β-NA),而在取食BR-S-10的种群中仅占2.6%(α-NA)和1.3%(β-NA).取食中棉12的棉蚜对β-NA与α-NA活性的比值为0.79,而取食其它棉花品种的种群β-NA与α-NA活性比值均大于1.用中棉12饲养的棉蚜对α-NA和β-NA活性均低于种群平均值的个体(CE1型)占26%;均高于平均值的个体(CE2型)占19%;对α-NA活性高于平均值,对β-NA活性低于平均值的个体(CE3型)占31%;对α-NA活性低于平均值,对β-NA活性高于平均值的个体(CE4型)占24%.取食其它6个棉花品种的棉蚜中,CE1和CE2型的比例分别为49.4—64.0%和23.4—47.2%,明显高于取食中棉12的种群,而CE3和CE4型个体仅占0—7.6%和3.4—10.4%,明显低于取食中棉12的种群.说明寄主植物对棉蚜羧酸酯酶的量和质均有影响.     

THE DISTRIBUTION OF APHID INFESTATION IN RELATION TO LEAF AGE

Infestations of apterous Aphis fabae Scop, on potted sugar beets have been followed in detail for several weeks. The plants were somewhat stunted and their crowns presented an unusually complete series of leaf ages. Records were kept of the changing number and size of the leaves and of their stage of growth. Parallel records were kept of the changing population of aphids on every leaf, and the figures are analysed in various ways to show how suitability for the aphids varied through the life cycle of the leaves.
The leaves were very suitable when young, became unsuitable as they matured, became suitable again just after maturity and then unsuitable again as they senesced. But among leaves at any given stage, those which were growing or senescing rapidly were more suitable than those changing slowly, unless the rate of senescence was very high. The differences of population density on different-aged leaves were due largely to the preferences exercised by the apterous adults. The added effect of differences in the fecundity of these mothers while feeding on different leaves was not excluded, but could not be assessed. It is concluded that the physiological development of the plant as a whole determines, through the growth and senescence among its total complement of leaves, the progress and pattern of its aphid infestation.     

INCREASE IN CELL WALL SURFACE AREA DURING ENLARGEMENT OF CAMBIAL DERIVATIVES IN ABIES CONCOLOR

Wilson , Brayton F. (U. California, Berkeley). Increase in cell wall surface area during enlargement of cambial derivatives in Abies eoncolor . Amer. Jour. Bot. 50(1): 95–102. Illus. 1963.— Dimensions of fusiform cells (tracheids and sieve cells) and ray cells were measured from samples of the 1960 xylem and phloem increment of 5 trees felled at monthly intervals from April through July, 1960. Calculations using these measurements gave the magnitude, direction and rate of increase in cell wall surface area during enlargement. Although 14 times more tracheids than sieve cells were produced, both cell types enlarged mostly in a radial direction (up to 400%) at the same rate (20–33 × 10³μ² wall surface area/day) to the same final size. Fusiform cambial cells doubled their wall area between successive periclinal divisions. Calculations showed that ⅞ of this increase was in the radial walls of the daughter cells at a rate comparable to that in enlarging tracheids and sieve cells; the other ⅞ was from cell plate formation at an estimated rate of 187–327 × 10³μ²/day. Enlargement of derivatives in the radial direction largely determined the amount of increase in wall area. Besides radial enlargement, tracheids also elongated (up to 13%) and phloem cells enlarged tangentially (sieve cells up to 36%; pholem ray cells up to 60%). The relationships of enlarging tracheids and xylem ray cells are discussed, and it is suggested that slippage may occur between the developing walls.     

MITOTIC ACTIVITY IN THE CAMBIAL ZONE OF PINUS STROBUS

Mitotic activity in the cambial zone of 20-year-old Pinus strobus L. trees was determined quantitatively, using mitotic counts from serial tangential sections of sample pieces. Counts from nine cores 1.6 mm in diameter from each sample piece were averaged and expressed as the number of mitoses per core with the sampling error. Estimation of the number of cambial zone cells per core permitted calculation of mitotic indices. In the fourth internode from the ground the first mitoses were observed on April 15 and the last on September 15. The number of mitoses per sample piece was comparable throughout each internode at any one sampling, but the number was higher in internodes within the crown than in those below it. Mitotic index was not appreciably higher within the crown, but it decreased from 3.7 in spring to 2.0 in fall. An internode in the crown sampled May 11–13 showed afternoon peaks in mitotic activity, but an internode below the crown showed no peaks, nor did other internodes sampled later in the season.     

TYPES OF CAMBIAL ACTIVITY AND WOOD ANATOMY OF STYLIDIUM (STYLIDIACEAE)

Three types of cambial activity, two hitherto unreported, are described for Stylidium. The four species of sect. Rhynchangium of subgenus Nitrangium have woody cylinders in upright stems. In these a cambium formed beneath the endodermis produces a determinate quantity of fibers, vessel elements, and interxylary phloem strands toward the inside but no derivatives toward the outside; this was correctly reported by Van Tieghem and Morot (1884a) but doubted by subsequent workers. The same species have lignotubers in which a cambium produces contorted xylem (mostly vessels) to the inside, phellem toward the outside. In S. glandulosum and S. laricifolium a cambium formed beneath the endodermis produces an indeterminate quantity of xylem (fibers and vessel elements) and interxylary phloem toward the inside, nothing toward the outside. The xylem is rayless and lacks axial xylem parenchyma. These three modes of cambial activity represent innovations within Stylidiaceae. The family has a wholly herbaceous ancestry if one can judge from the total lack of cambial activity in vascular bundles.     

伪潜育土季节性滞水条件下大冷杉毫根动态的研究(Abies grandis Lindl.)

本文对一个25年生大冷杉林在伪潜育土至45cm矿质土壤里,从1987年晚秋滞水期至1988年生长旺盛期的毫根量动态及化学组成变化进行了研究。 滞水期土壤中死根量(5558kg DS/ha)显著高于活根量(3594kg DS/ha)。生长旺盛期初,活根量增加约50％,死根量降低约27％。经过夏季至生长旺盛期末,活根量仍略有增加,死根量继续降低。毫根化学组成分析显示,滞水期活根中K、Mg及Zn离子含量显著低于生长旺盛期,Mn离子含量则明显高于生长旺盛期。这一结果表明,除了与季节性相关的生长节奏因素外,大冷杉毫根生物量的变化主要是由滞水状况所致。     

伪潜育土季节性滞水条件下大冷杉(Abies grandis Lindl.)毫根动态的研究

本文对一个25年生大冷杉林在伪潜育土至45cm矿质土壤里,从1987年晚秋滞水期至1988年生长旺盛期的毫根量动态及化学组成变化进行了研究。滞水期土壤中死根量(5558kg Ds／ha)显著高于活根量(3594kg DS／ha)。生长旺盛期初,括根量增加约50％,死根量降低约27％。经过夏季至生长旺盛期末,活根量仍略有增加,死根量继续降低。毫根化学组成分析显示,滞水期活根中K、Mg及Zn九离子含量显著低于生长旺盛期,Mn离子含量则明显高于生长旺盛期。这一结果表明,除了与季节性相关的生长节奏因素外,大冷杉毫根生物量的变化主要是由滞水状况所致。     

EFFECT OF ISOLATION OF BARK ON CAMBIAL ACTIVITY AND DEVELOPMENT OF XYLEM AND PHLOEM IN TREMBLING ASPEN

Circular patches of bark were surgically isolated on the sides of trembling aspen (Populus tremuloides Michx.) trees at breast height at various times during the dormant and growing seasons. Subsequently, samples of wood and attached bark were taken from isolated and control sites to determine the effects of isolation of the bark on cambial activity and xylem and phloem development. In control trees cambial activity and xylem and phloem development occurred normally. Isolation of bark during the dormant season (in November, February, or March) did not prevent initiation of cambial activity and of phloem differentiation in spring but continued normal cambial activity and phloem developmented were prevent. Xylem differentiation was essentially prevented by isolation of tissues during the dormant season. The ultimate effect of isolation of the bark on the cambium, either during the dormant season or during the growing season, was subdivision of all fusiform cambial cells into strands of parenchymatous elements; the ultimate effect on the newly formed phloem was early death of the sieve elements. The most conspicuous effect of isolation of the bark after xylem differentiation had begun was the curtailment of secondary wall formation. Shortening of cells of the cambial region was reflected in the length of the vessel members which differentiated from such cells. These results indicate that normal cambial activity and xylem and phloem development require a supply of currently translocated regulatory substances from the shoots.     

构树形成层的活动周期及其淀粉贮量的变化

在构树（Ｂｒｏｕｓｓｏｎｅｔｉａ ｐａｐｙｒｉｆｅｒａ （Ｌ．） Ｖｅｎｔ．）形成层活动周期中,每年７月末以后,未成熟的木质部和韧皮部逐渐减少,成熟的木质部和韧皮部急剧增多。８月初开始分化晚材。进入９月后木质部的形成逐渐停止,而一个半月以后才停止形成韧皮部。淀粉贮量的消长与形成层的活动周期有很强的相关关系。早春形成层恢复活动后,淀粉贮量逐渐减少直至消失。尔后,形成层活动减慢,特别是木质部分化停止后,淀粉又开始积累。当韧皮部分化也停止后,淀粉又消失,直至翌年１月才重新积累,这似乎与两个休眠期的转化有关     

溴氰菊酯对黄瓜幼苗过氧化氢酶活性的影响

用100mgL-1的溴氰菊酯喷施黄瓜幼苗2d后,体内过氧化氢酶活性升高49．65％．150mgL-1的溴氰菊酯使体内蛋白质含量升高33．25％,使DNA和RNA含量分别上升15．39％和11．49％．而500mgL-1的溴氰菊酯却使过氧化氢酶活性降低6．94％,蛋白质、DNA和RNA含量分别降低10．22％、9．85％和16．20％．溴氰菊酯对高体的过氧化氨酶活性无影响．放线菌酮对溴氰菊酯影响蛋白质含量和过氧化氢酶活性有抑制作用．初步讨论了低浓度溴氰菊酯影响过氧化氢酶活性的可能原因．     

温度对蜥蜴腓肠肌ATP酶活性影响的研究

本文研究了荒漠沙蜥（ｐｈｒｙｎｏｃｅｐｈａｌｕｓ Ｐｒｚｅｗａｌｓｋｉｉ Ｓｔｒａｕｃｈ）和密点麻蜥（Ｅｒｅｍｉａｓ　ｍｕｌｔｉｏｃｅｌｌａｔａＧｕｅｎｔｈｅｒ）腓肠肌肌球蛋白钙激活ＡＴＰ酶活性对温度的依赖关系。结果表明，荒漠沙蜥腓肠肌ＡＴＰ酶的最适温度为３７℃，密点麻蜥腓肠肌ＡＴＰ酶的最适温度为３５℃。两种蜥蜴ＡＴＰ酶最适温度的不同与它们所喜好的温度有很好的相关性。ＡＴＰ酶活性在同种个体大小之间也存在差异。ＡＴＰ酶的生化调节可能在蜥蜴对温度适应上起重要作用。     

SO_2污染油菜对桃蚜的影响(英文)

用含20－160nl／lSO2的空气熏气处理过的油菜在25℃下饲养桃蚜MyzusPersicae,研究SO2污染对这种蚜虫的影响。结果表明,蚜虫的反应与SO2剂量有关：低、中浓度的SO2处理显著促进了桃蚜的生长和繁殖;SO2浓度约为80nl／l时,它们的反应最敏感,若蚜的平均相对生长速率（MRGR）、成蚜的繁殖力和种群的内禀增长力（rm）分别比对照组增加31．5％、89．8％和42．7％;高浓度SO2污染的油菜严重抑制桃蚜的生长和繁殖。对被处理植物营养成分的分析表明,SO2污染引起的蛋氨酸相对含量变化可能是造成这种剂量—反应关系的主要原因。