INFLUENCE OF MANNITOL ON ABSORPTION AND RETENTION OF RUBIDIUM BY EXCISED CORN ROOTS

Excised root segments of corn were subjected to osmotic stress by immersion in solutions of mannitol before, during, or after a period of Rb absorption. Both the time course of uptake (or loss) and selectivity of uptake were studied. Stress before or during the absorption period reduced Rb absorption to 20 % or less of that of controls, whereas it had no detectable influence on the constancy and selectivity of uptake. Stress imposed following a period of Rb accumulation caused root segments to lose only slightly more Rb than controls during the first 30 min, after which rates of change were insignificant in both. Segments stressed after the Rbabsorption period retained from 70–90 % as much Rb as did the controls, even after two hours. The comparatively great quantitative difference between effect of stress on uptake and its effect on loss is interpreted to mean that the mechanism of stress-induced reduction of ion absorption cannot be adequately explained on the sole basis of increased efflux of ions.     

THE DOLLAR VALUE OF PRODUCT QUALITY: THE EFFECT OF PRICING VERSUS OVERALL LIKING ON CONSUMER STATED PURCHASE INTENT FOR PIZZA

This paper investigates the combined effects of price and product quality (overall liking) on the acceptance of restaurant pizza pies. The results reveal that when a panelist evaluates both liking and purchase intent (with price attached to the purchase intent question), product quality is a significantly stronger determinant of purchase intent than is the stated item price. For instance, a 10% increase in product quality (viz., liking) has the same effect on purchase intent as a 20% reduction in item price. The results are surprising, because for other categories investigated by the same method price is a significantly greater determinant of purchase intent. In terms of predictability, 57% of the variation in purchase intent ratings is accounted for by liking, 24% of the variation is accounted for by price, and the remaining 19% is due to error.     

INFLUENCE OF UPWARD WATER TRANSLOCATION ON UPTAKE OF IONS IN CORN PLANTS

Smith , Richard C. (Rutgers U., New Brunswick, N. J.) Influence of upward water trans location on uptake of ions in corn plants. Amer. Jour. Bot. 47 (9): 724–729. Illus. 1960.—Experiments were performed in which segments of corn roots were surrounded by a nutrient solution which contained radioactive phosphorus, while a second nutrient solution containing no phosphorus was caused to flow upward through the xylem. Results indicate that phosphorus moves radially across the root into the xylem in the absence of any radial water movement, but that increased rate of water movement upward through the xylem increases the rate of radial or inward movement of ions. Results of experiments in which root segments were treated with sodium azide suggest that the movement of phosphorus across the root is independent of, and in competition with, the process of phosphorus accumulation by the cells of the cortex.     

植物源调节剂对玉米生长的影响

植物源调节剂是利用豆科和菊科植物为原料 ,首次研制的一种植物生长调节剂 ,对玉米萌发有促进作用 ,尤其表现在促进根生长。在苗期、拔节期叶面喷施 ,提高生物产量 2 1 4 3% ,增加千粒重 4 2 0g ,增产率2 1 95 %。使用浓度为 80× 10 -3 g/L或 10 0× 10 -3 g/L使用方法是拌种和苗期、拔节喷施     

光周期和温度对亚洲玉米螟滞育形成的影响

短光照是引起玉米螟滞育的信息,处在北纬35°—36°,东经112°—113°的山西沁水玉米螟种群,在太原控制温度25℃,人工饲料饲养下测定,其临界界光周期为14小时30分钟。当光照少于此临界期,诱发滞育;而多于此临界期,则回避滞育。对于玉米螟幼虫任一单独龄期给予短光照处理,不能或几乎不能引起滞育;而相邻虫龄连续接受短光照处理,则可导致滞育。连续接受短光照处理的时间愈长,滞育率也愈高。幼虫对光照刺激反应的敏感期为自孵化后至5龄末进入滞育前的整个阶段,而非仅为3—4龄。高温在一定程度上抑制短光照诱发滞育的作用;低温在一定程度上抑制长光照回避滞育的作用。以长光照累代处理人工饲料饲养的亚洲玉米螟至三,四十代以上、如经短光照处理则照常发生滞育,其滞育特性仍未改变。     

玉米浆对玉米粉和木薯淀粉发酵甘油的影响及二者的比较

以玉米粉和木薯淀粉为原料 ,比较了二者的液化和糖化 ,结果表明 :在相同条件下 ,木薯淀粉液化时间较短 ,玉米粉液化时间较长 ,但二者的液化液均较易糖化。然后分别以玉米粉和木薯淀粉糖化液为原料 ,用耐高渗酵母发酵生产甘油 ,研究了玉米浆对二者甘油发酵的影响并对二者进行了比较 ,结果表明 :当玉米粉和木薯淀粉糖化液还原糖含量分别为 2 5 % ,尿素为 0 .2 % ,pH为 4 .5时 ,用玉米粉糖化液发酵甘油时可不添加玉米浆 ,甘油产量最高可达 2 % ,而用木薯淀粉糖化液发酵甘油时 ,适宜的玉米浆为 0 .15 % ,甘油产量最高可达 4 .9%。对二者的比较结果表明 :用玉米粉糖化液为发酵原料时 ,发酵时间较短 ,残糖降低较快 ,甘油产量较低 ,在 36h之后 ,甘油开始反耗。而用木薯淀粉糖化液发酵时 ,发酵时间较长 ,残糖降低较慢 ,甘油产量较高 ,在 72h之后 ,甘油开始反耗。     

玉米螟赤眼蜂的生物学特性及其利用

玉米螟是玉米、杂粮、棉花等作物的大害虫。赤眼蜂是抑制玉米螟危害的重要因素之一。经调查发现我国寄生于玉米螟卵的赤眼蜂有8种,其中玉米螟赤眼蜂Trichogramma ostrininae Paag et Chert占总数的98%以上,分布亦广,是优势种。 我省释放人工繁殖的赤眼蜂防治第一代玉米螟的效果达80%左右,相当于施用滴滴涕颗粒剂;防治第二代玉米螟因受不良气候条件的影响,防治效果不稳定。     

臭氧对墨西哥豆瓢虫取食和生长的影响

本文报道在美国农业研究中心用臭氧在室内熏蒸和田间开顶熏蒸植物,用此饲养墨西哥豆瓢虫的实验,以及熏蒸后植物体内某些化合物含量变化的测定.结果表明,墨西哥豆瓢虫(Epilachna varivestis Mulsant)喜食臭氧(O₃)污染的植物,幼虫取食O₃污染植物后蛹显著重于取食未受污染植物所形成的蛹.根据豆瓢虫食性和植物体内糖含量的测定,可以认为,低浓度O₃污染导致植物体内糖含量的增加,是促使豆瓢虫取食量和蛹重增加的重要因素.     

二氧化硫对墨西哥豆瓢虫的影响

空气污染对害虫的影响,国内尚无研究报道。本文报道了作者在美国农业研究中心植物胁迫实验室进行的部分工作。实验结果表明,在0.30ppmSO_2的作用下,墨西哥豆瓢虫(Epilachna varivestis)的取食量和蛹重增加;与未受污染的寄主植物相比,豆瓢虫偏食受污染的植物;而且有嗜食含较高糖分寄主植物的倾向;在污染空气中长成的成虫可消耗更多的植物物质。     

次声对前庭和耳蜗的影响

本研究发现:(1)140dB SPL次声暴露引起耳蜗功能和形态的永久性损伤.(2)120dB SPL次声暴露对耳蜗功能和形态仪是暂时性损伤.(3)120dB SPL和140dB SPL次声暴露都能引起前庭功能和形态的变化.(4)低声强(120dB SPL)次声暴露仅受累前庭,高声强(140dB SPL)次声暴露,前庭和耳蜗皆受累.(5)次声对前庭损伤要比耳蜗明显.     

NUTRITION OF CHYTRIOMYCES AND ITS INFLUENCE ON MORPHOLOGY

The nutrition and its influence on some morphological characteristics of one isolate of Chytriomyces aureus Karling and two isolates of C. hyalinus Karling, one with and one without resting bodies, was studied. All three isolates required exogenous thiamine for optimum growth. Glucose, fructose, mannose, maltose, cellobiose, and starch supported good or moderate amounts of growth of all the isolates. Galactose, arabinose, xylose, ribose, sucrose, lactose, and raffinose supported little or only trace amounts of growth of C. hyalinus, with resting bodies, but failed to produce any growth of C. aureus and C. hyalinus, without resting bodies. All isolates utilized ammonium [NH₄NO₃, (NH₄)₂SO₄, NH₄Cl] as nitrogen sources but were unable to utilize nitrate (KNO₃) and nitrite (KNO₂). All isolates were able to grow at pH ranges of 5–8; the optimum pH range was 6.5. Both isolates of C. hyalinus were able to grow at a temperature of 10–30 C, whereas C. aureus did not grow below 15 C or above 25 C. Sporangial size was influenced by varying temperature levels, pH ranges, vitamins, carbohydrates, and nitrogen sources, while the morphology and sizes of zoospores, lipoid globules, apophyses, and rhizoids were little affected. The similarity of response exhibited by both species of Chytriomyces to various nutrients may suggest that these are closely related taxa.     

丛枝菌根真菌对玉米和棉花内源激素的影响*

在温室盆栽条件下研究了丛枝菌根（Ａｒｂｕｓｃｕｌａｒ　ｍｙｃｏｒｒｈｉｚａｓ,ＡＭ）真菌：ＧｉｇａｓｐｏｒａｒｏｓｅａＮｉｃｏｌ．＆Ｓｃｈｅｎｃｋ、Ｇｌｏｍｕｓ　ｍｏｓｓｅａｅ（Ｎｉｃｏｌ．＆　Ｇｅｒｄ．）Ｇｅｒｄｅｍａｎｎ　＆Ｔｒａｐｐｅ和Ｇｌｏｍｕｓ　ｖｅｒｓｉｆｏｒｍｅ　（Ｋａｒｓｔｅｎ）Ｂｅｒｅｈ对玉米和棉花植株内源激素的影响。结果表明,ＡＭ真菌在正常供水和干旱条件下均能显著提高玉米和棉花植株叶片和根内玉米素、生长素和赤霉素的含量,并降低脱落酸的含量。在植物体内含磷量、生长量及其生长发育阶段等一致、仅存在接种与不接种唯一差异条件下,供试ＡＭ真菌同样能改变玉米和棉花植株内源激素的平衡状况。接种处理植株的脱落酸含量与气孔阻力呈正相关关系。表明玉米和棉花植株抗旱性和生长状况的改善与ＡＭ真菌改变内源激素的平衡状况有关。接种ＡＭ真菌的植株表现较强的抗旱性;其生长量也显著大于不接种的对照。ＧＩ．ｖｅｒｓｉｆｏｒｍｅ的效应最大。     

光与激素对于杜鹃花种子发芽的作用

本文报道24种杜鹃花种子的光照发芽试验,结果表明杜鹃花种子是需光性种子。所有种子的发芽都必须有光照,假如在黑暗条件下进行发芽试验,种子的发芽率几乎等于零。杜鹃花种子的发芽受光敏素的控制,红光促进种子发芽,远红光可以逆转这种促进作用,种子发芽与否取决于最后一次照射的光质。 不同种的杜鹃花种子对光的敏感性存在差异。敏感的种子可以在蓝光,短光照时间下正常发芽,并且它们的需光要求可以被1000 ppm赤霉素所代替。迟钝的种子发芽则要求红光和长光照时间,1000 ppm赤霉素不能代替光,光和赤霉素并用具有增效作用。