钾肥对向日葵增产潜力的影响

１９９０—１９９２年三年试验结果表明，尽管只施氮磷肥可获得高产，但在施氮磷肥的基础上按比例配施钾肥，可进一步提高向日葵的产量．钾肥的最佳经济施肥量为１５０公斤Ｋ２Ｏ／公顷，Ｎ、Ｐ２Ｏ６、Ｋ２Ｏ最适比例为２∶１∶２．     

THE EFFECT OF SHEEP URINE ON THE GERIMINATION AND EARLY ESTABLISHMENT OF A COMMON WEED GRASS

Sowings of annual meadow grass ( Poa annua ) were made in pots of soil which had been treated with sheep urine, with urine diluted × 50, or with water as a control. The treatments were applied before, at, and after sowing.
Urine, whether applied at sowing time, or eleven days before or after, significantly reduced the germination or establishment of the weed grass.
Diluted urine tended to reduce the number of established seedlings when applied at or shortly after sowing.
In a subsidiary experiment the number of viable seeds in soil taken from pastures which had received no urine for four years were compared with those from soil under pastures receiving urine. The difference was not significant.     

THE EFFECT OF METHOD OF SOWING ON THE ESTABLISHMENT OF GRASS SEED CROPS

Methods used by growers to establish seed crops of perennial ryegrass, cocksfoot, timothy and meadow fescue have been examined. While satisfactory establishments were obtained by sowing perennial ryegrass broadcast, cocksfoot, timothy and meadow fescue should be sown in rows, especially if they are to be sown under a cover crop.     

粉锈宁对花生幼苗生长、光合和呼吸的影响

用100或300ppm的粉锈宁(三唑酮)溶液喷施花生幼苗后,植株矮壮,根系较发达,根冠比大,减少叶面积,提高叶绿素含量、二磷酸核酮糖羧化酶的活性和光合速率,而呼吸速率没有很大差异,增加植株鲜重和干重,有利于作物增产。     

THE EFFECT OF DUNG AND URINE AND ITS INTERACTIONS WITH APPLIED NITROGEN, PHOSPHORUS AND POTASSIUM ON THE CHEMICAL COMPOSITION OF PASTURE

The importance of the grass/clover balance of a pasture in determining the effects of manurial returns and fertiliser applications on the chemical composition of the sward is shown.
The response to applied nitrogen was very dependent on the presence or absence of the animal excrements. For example, the N recovery from an application of 18 cwt. per acre of nitro-chalk was only 2% in the absence but 68% in the presence of the grazing animal.
Urine caused a marked increase in the N and K content and the yield of pasture, particularly when returned in quantity to a high-producing grass-dominant sward, and at the same time tended to depress the Ca, P and Mg content. Urine K was superior to fertiliser K, per pound of K returned or applied, in raising the K content of the pasture.
By comparison, dung had little direct effect on chemical content; even when returned in large amounts it affected the Ca and K content of the pasture to a relatively small extent. The P returned in the dung had little effect on the P content of the pasture and was inferior to superphosphate in this respect.
Together, as in normal grazing, dung and urine tended to counter or enhance their individual effects.
There was a positive correlation between the Mg and P content of the pasture and a negative correlation between Mg and K. Brief mention is made of the possible importance of the nutrient balance in pasture as a factor in animal health.     

THE EFFECT OF SEED WEIGHT AND DEPTH OF SOWING ON THE EMERGENCE AND EARLY SEEDLING GROWTH OF PERENNIAL RYEGRASS (LOLIUM PERENNE)

Seed of S24 perennial ryegrass of two weight ranges, 0.9–2.1 and 2.5–3.6 mg, were sown in soil at depths of 1.25, 2.5, 5.0 and 7.5 cm. Seedling growth was studied during the 3 weeks following germination.
Seeds of both weight ranges germinated equally well at soil depths down to 7.5 cm. However, the number of shoots that emerged was reduced as the sowing depth increased. At similar depths of sowing, seedlings from the heavy seed were heavier and developed more leaves and tillers than those from light seed. Deeper sowing reduced seedling weight and the rate of leaf- and tiller-production. After emergence, the relative growth rates of the seedlings which grew from seed of both weight ranges were similar at those depths of sowing which permitted the highest proportion of emerged shoots to seeds sown. This indicates that the weight advantage gained by the seedlings that developed from heavy seed during their non-photosynthetic stage of growth was maintained, and was not increased by a greater relative growth rate after photosynthesis began.
The implications of the findings are discussed in relation to plant breeding, commercial seed production and sward establishment.     

低温预处理对大豆萌芽活力及其活性氧代谢的影响

采用低温（3-5℃）处理大豆种子（黑脐91-1）能显著提高种子萌发率和萌芽活力，其中以处理15天的效果更为明显，在大豆萌发过程中，低温处理组的外渗电导率明显较对照组低，呼吸速率升高的速度较对照组更快，超氧物歧化酶（SOD）和过氧化物酶（POD）的活性均显著高于对照，超氧阴离子（O2^-)含量和脂质过氧化产物丙二醛（MDA）的积累量均明显低于对照，表明种子萌发前经低温预处理能有效提高大豆种子萌发时活性氧代谢水平，有利于好苗、壮苗的形成。     

pH对油菜幼苗细胞膜及细胞保护系统的影响

皖油9号种子在pH3～11的溶液中培养4d的测定结果表明，pH5～8的缓冲液培养的油菜幼苗细胞膜透性低，MDA含量较低，SOD、POD、CAT活性高，组织可溶性蛋白质含量高；pH小于5或大于8时，MDA含量升高，细胞膜透性增大，SOD、POD、CAT活性及可溶性蛋白质含量下降。     

油料种子超干处理与种子活力及脂质过氧化的关系

油菜、芝麻、花生种子经过超干处理后，发芽率不受影响，但发芽指数和活力指数均低于对照。发芽前经过“回水”处理，则与对照基本一致．超干及其老化的种子，外渗液的电导率明显低于对照；种子过氧化氨酶、过氧化物酶和超氧物歧化酶等酶系统保持完好；丙二醛和挥发性醛类物质相应减少。     

THE EFFECT OF WEEDS, AND THEIR CONTROL BY MCPA SPRAYING, ON THE ESTABLISHMENT OF PERENNIAL RYEGRASS AND COCKSFOOT IN THE KENYA HIGHLANDS

The vigour of perennial ryegrass and cocksfoot after spraying with the sodium salt of MCPA during establishment was estimated from their yields in small-plot cutting experiments on weedy land. Where the weed yields of control plots was of the order of a ton of air-dry matter an acre (mostly Spergula arvensis L.), spraying at up to 1·2 1b. acid equivalent an acre caused twofold to threefold increases in grass yields. The optimum time to spray perennial ryegrass was at the three- to four-leaf stage or 26 days after sowing; for cocksfoot, which appeared more susceptible to the herbicide, spraying at the tillering stage, or about 40 days after sowing, was best. Increasing the seed rates of ryegrass produced transitory increases in yields while decreasing weed yields. Increasing phosphate or nitrogen caused decreases in weed yields. Although the former gave a large increase in weed yield in the first cut this was offset by a large decrease in the second cut. There was an indication that the level of nitrogenous manuring affected the toxicity of the herbicide to the grasses.     

马铃薯需钾特性及钾肥效应

试验结果表明,钾对马铃薯营养生长有明显促进作用。团棵期施钾处理株高较对照平均增加３．２ｃｍ,鲜重增加１１．６ｇ;盛花期分别增加２．４ｃｍ和４９．１ｇ。植株含钾量随着植株生物量的增大而减小,前期植株中钾的含量３．８５％～４．６２％,后期钾的含量为１．６３％～４．１９％。植株吸钾量则随着生物量的增大而增加,前期０．６～０．８ｇ／盆,后期４．１２～５．８６ｇ／盆。施钾处理较对照平均增产６．８％,不施钾土壤速效钾和缓效钾均有下降,分别降低２７．７和５３．０ｍｇ／ｋｇ。     

植物激素对咖啡幼苗叶片乙醇酸氧化酶活性及光合作用的影响

咖啡幼苗叶片提取过程中,由于单宁等次生物质存在,使乙醇酸氧化酶(GAO)容易失活,加入40％(w/w)PVP(聚乙烯吡咯啉酮K值27～33)作保护剂,GAO活性恢复并达到最大。用不同浓度的各种激素对咖啡幼苗叶片处理时,GAO活性都受到了抑制,其中IAA,GA_3,CTK和乙烯利的抑制随浓度增加而增加,抑制效应的顺序是100ppm>50ppm>10ppm,而ABA却相反,随浓度增加而减弱。相同浓度的各种激素对GAO活性及光合作用的影响,表现出相似的规律性,在处理12小时后开始发生抑制,随着时间的推移,GAO活性逐渐下降,到一定时间后逐渐回升或在回升线上波动,到处理144小时,基本上恢复到对照水平。激素对GAO与光合作用的抑制,表明了光呼吸与光合作用存在着伴随关系。     

磷素水平对不同大豆品种钾素吸收效率的影响

通过原子吸收分光光度计法研究了施磷量对不同大豆品种各器官及全株吸收钾素营养的影响,结果表明:施磷量对不同大豆品种植株及各器官钾素含量有较大影响.不同品种不同处理全株及各器官钾素含量从分枝期逐渐增加,开花期达到高峰,随后下降至成熟期;同一品种不同处理间钾素含量三个品种都是P10处理全株及各器官钾素含量最高,整个生育期高磷或不施磷都会影响钾素含量,只有适宜的施磷才能促进钾素含量达到最高峰.同一处理不同品种全株及各器官钾素含量在品种间没有明显的变化规律.     

硝态氮与氨态氮对大豆幼苗生长及氮素积累的影响

无论是ＮＯ３＾－－Ｎ，还是ＮＨ４＾＋－Ｎ使用单一氮源大豆幼苗长势均不如二者混合。以ＮＯ３＾－－Ｎ或混合氮为氮源时，幼苗生长受ｐＨ值影响较小，而以ＮＨ４＾＋Ｎ为氮源时，ｐＨ７．５时幼苗生长明显优于ｐＨ５．５。在本试验设计的七种氮素形态配比中，大豆茎叶全氮含量高低的顺序为ＮＯ３＾－－Ｎ：ＮＨ４＾＋－Ｎ３：１〉５：１〉１：１〉１：３〉１：５〉１：０〉０：１，与株高及鲜重的顺序相一致。随着营养液中ＮＯ３＾     

施钾对增强大豆抗旱性的影响

施钾提高了大豆植株含钾量，产生一系列的抗旱特性如：根，茎，叶的维管束的发达，利于吸收和贮存水分及养分。由于细胞壁和厚角组织厚，保水力强，在高温条件下，能抗高温。质膜透性小，气孔阻力大，蒸腾速度减慢，束缚水含量高等。故大豆施钾可提高抗旱性而增产。     

包衣大豆萌发期、苗期生理与形态指标研究

通过对种衣剂包衣的大豆种子萌发期、苗期生理指标、形态指标测定结果表明：包衣的大豆种子发芽率,呼吸强度、苗期可溶性糖含量、叶绿素含量、株高和根比、胚根长和粗等指标均高于对照。     

甘蓝型油菜芽粒形成的时期及对发芽出苗率影响的研究

在油菜成熟前的角果内就已经发芽(胚根突破种皮,并有不同程度伸长)的籽粒称为芽粒,具有芽粒性状的品种和资源材料从开花后35天左右就有芽粒产生,并随时间的增加而不断增多的趋势。不同品种和同品种不同个体(或株系)间芽粒的有无和多少差异较大,而与具有芽粒性状单株的花序部位无关。具有芽粒的种子其发芽势(率)和出苗率比正常种子均有不同程度下降。     

贮藏方式和年限对油菜种子生活力及幼苗素质的影响

油菜种子的生活力(发芽率、发芽势、利用系数)随贮藏时间的延长而降低,它们呈一复合曲线关系。油菜种子的有效贮藏时间,干燥贮藏为4年,木箱贮藏为2年。在有效贮藏期内油菜幼苗单株干重、叶面积和移栽后的植株干重及出叶速度差异不明显。但超出有效贮藏期,种子生活力显著降低,幼苗素质很差。     

不同施磷量对大豆苗期根系形态性状的影响

通过盆栽试验，对不同磷施用量条件下的大豆根系形态进行研究。结果表明，磷显著增加根系干重、根长、根表面积和根体积，在低磷P50（50mg／kg）处理下，根干重、根长、根表面积和根体积分别比P0（0mg／kg）处理增加88．0％、97．1％、101．7％和104．9％。适量的磷可促进根系的生长，增大根系在土壤中的养分吸收空间。磷对大豆根系形态性状的影响主要表现在根量及根长的增加上，而与不同粗细的根系分布比例关系不大。在不同施磷处理间，高磷P100（100mg／kg）处理的根系性状弱于低磷PSO处理。磷对根系的促生长作用是有一定范围的，过高的磷不但不会进一步改善根系性状，反而对其生长产生抑制作用。     

THE EFFECT ON THE SOIL OF THE COMPONENTS AND MANAGEMENT OF A LEY

The effect of four grasses, and four methods of utilizing the herbage, on the root weight, the proportion of organic matter in the soil and the water-stability of the soil aggregates was measured over a period of three years. The grass species in the sward had a greater effect upon the measurements than had the methods of management. Of the grass species, Lolium perenne produced the greatest root weight and highest percentage of organic matter in the soil.