根茎禾草发育过程中糖含量与能值分配规律的研究

研究表明根茎类禾草含糖量和能值分配存在明显的发育时期、发育器官和植物根茎类型的差异。一般根茎类禾草含糖量在地上部呈单峰曲线 ,前营养期高于后营养期 ;地下部呈“S”型曲线 ,后营养期高于前营养期。根茎类禾草总含糖量和地上部含糖量是 :短根茎大于长根茎 ;地下部含糖量是 :长根茎大于短根茎 ;穗部是 :短根茎大于长根茎。根茎类禾草有性生殖器官的能值分配较低 ,一般在 5～ 1 0 %之间 ,短根茎高于长根茎 ;地上部的能值分配较高 ,一般在 40～ 80 %之间 ,短根茎明显高于长根茎 ,前营养期高于后营养期。地下部的能值分配一般在 1 0～ 50 %之间 ,短根茎明显低于长根茎 ,后营养期高于前营养期。根茎类禾草在生育期内 ,地上部与地下部的能值分配存在明显的互补性 ;在前营养期地上部营养器官与生殖器官的能值分配存在明显的一致性。糖含量与生长发育相关分析达极显著或显著正相关 ,这表明糖含量与根茎类禾草的生长发育有较高的一致性。     

根茎类禾草发育特性的研究

本项研究结果表明 ,根茎类禾草的生育期普遍较长。一般情况是长根茎禾草的有性生殖期相对较短 ,而其无性生殖期相对较长 ;短根茎禾草则相反。不同根茎类型的禾草在生长发育过程中地上部和地下部的发育动态有不同的变化规律。地上部重量差异表现为短根茎 >中根茎 >长根茎 ,三者在地上部生长均呈现单峰曲线 ;地下部根系重表现为长根茎 >中根茎 >短根茎 ;根冠比的变化趋势三者均呈现由高—低 -高的“U”型曲线 ,根冠比大小表现为长根茎>中根茎 >短根茎。根茎类禾草中根茎的发育程度与种子的休眠程度有明显的关系 ,根茎越发达 ,其无性繁殖能力越强 ,种子的休眠程度越严重     

呼伦贝尔草原植物功能群对围封及放牧的响应特征

植物功能群可以表征草地群落结构的复杂性和稳定性.文中以呼伦贝尔草原为研究对象,采用样线法开展植物群落样方调查,对比分析不同放牧强度下(轻度放牧-LG、重度放牧-HG、长期围封不放牧-EN)草地植物功能群(多年生根茎禾草-PRG、多年生丛生禾草-PBG、多年生杂草-FO、灌木及半灌木-SHS、一、二年生草本-AB、莎草-...     

盐胁迫对11种禾本科牧草根系细胞膜透性的影响

本研究采用电导法测定了盐胁迫下 1 1种禾本科牧草不同季节根系细胞膜透性的变化 ,实验结果表明 :1 1种禾本科牧草根系细胞膜透性与其耐盐性呈极显著负相关 ( r=-0 .993 ) ;1 1种禾本科牧草的耐盐性存在种 (品种 )间、季节间明显差异 ,评价结果与大田试验结果一致 ,因此根系电导率测定细胞膜透性可以作为植物耐盐性评价的指标之一。根系是评价多年生禾本科牧草 ,尤其是根茎类禾草耐盐性的较好的植物器官     

小麦族6种根茎型牧草叶表皮气孔特性与抗旱性的研究

本文对小麦族 6种根茎型牧草叶的气孔特性与抗旱性的关系进行了研究 ,结果表明 :6种禾草间气孔特性存在着基因型的本质差异 ;赖草属中 ,赖草叶对水分的蒸腾、气体交换的调控功能强于羊草和大赖草 ,其抗旱性强 ;在偃麦草属中 ,中间偃麦草叶的水分的蒸腾、气体交换的调控功能弱于其他 2种 ;在同种不同品种中 ,巴顿硬叶偃麦草叶的抗旱性强于茹莎娜硬叶偃麦草 ;6种禾草中 ,赖草属植物抗旱性强于偃麦草属植物。     

六种根茎类禾草种子产量构成因子和种子生产性能的研究

对 6种根茎类禾草的种子产量构成因子作了研究 ,并通过测试单穗种子数、结实率、千粒重及单位面积种子产量等指标对其种子生产性能进行了比较。由结果可知 ,巴顿牧冰草的种子生产性能最高 ,茹莎娜牧冰草的种子生产性能最低 ,其它 4种牧草居中。     

禾草克防除大豆田禾本科杂草的研究

禾草克(Nc—302)是由日产化学工业株式会社研制的一种新型除草剂,化学名称2-[4-(6-氯-2-喹嗯啉基氧化)—苯氧基]—丙酸乙酯,通用名Quizalofop—ethyl。禾草克是一种内吸选择性除草剂,主要由植物叶片吸收,传导全株积累于分生组织。禾草克能选择性杀死禾本科杂草的机制在于破坏生长点,同时也可以破坏新叶的基部组织。施药后敏感杂草叶片褪绿、坏死,7～10天全株枯死。由于禾草克在植物体内传导能力很强,因而能杀死多年生杂草的根茎。经世界各地试验证实,禾草克适用于包括大豆、棉花、甜菜、油菜在内的60余种作物,     

禾草克除草剂的施用技术

禾草克，也叫喹禾灵，是日本生产的一种内吸传导型灭杀禾本科杂草的茎叶处理除草剂。在禾本科杂草与双子叶作物间有高度选择性，对阔叶作物田间的禾本科杂草有很好的除草效果，茎叶可在几小时之内完成对药剂的吸收，再向植物体内上部和下部移动。一年生杂草在２４小时内药剂可传遍全株，２～３天新叶变黄停止生长，４～７天茎叶坏死，１０天内整株桔死，杀草速度快于稳杀得除草剂。多年生杂草受药后能迅速地向地下根茎组织传导，使根茎坏死，同样能够彻底杀灭。目前使用的剂型有禾草克１０％乳油和精禾草克５％乳油。一、适用范围１、适用于…     

三十五种菊科植物对吡氟禾草灵的敏感性差异

在测定35种菊科植物对除草剂吡氟禾草灵敏感性的基础上,选择部分植物从电解质漏出及丙二醛生成两方面研究吡氟禾草灵在菊科植物间的选择性及其机制。结果显示,在供试的35种受体菊科植物中只有硬毛刺苞菊、刺苞果和续断菊3种植物对吡氟禾草灵敏感,且前两者的敏感性明显高于后者,而其它32种植物即使在100μmol/L的高浓度下生长亦不受影响。进一步研究发现,对吡氟禾草灵敏感的硬毛刺苞菊和续断菊在药剂处理后均显示出大量的电解质漏出和丙二醛(MDA)生成,100μmol/L浓度处理后96h的电导率分别较不含药剂空白对照处理高28.56倍和1.39倍,处理后24h的丙二醛较对照高1.72倍和1.33倍,而在其它非敏感植物上均无显著差异。说明吡氟禾草灵在菊科植物间具有很高的选择性,且该选择性的形成与药剂在敏感植物上诱导膜脂质的过氧化及导致膜结构的破坏有关。     

马蹄金草坪杂草发生特点及防除技术研究

马蹄金草坪危害严重的杂草有稗草、凹头苋、香附子、粟米草、马唐、铁苋菜等.精禾草克对禾本科杂草的株防效达100%,且对马蹄金无明显药害.草除灵对香附子的株防效可达90%以上,并能部分杀死地下根茎,对其他阔叶类杂草株防效也达90%以上.胺苯磺隆用量少,价格低廉,也是马蹄金草坪的适宜除草剂.精禾草克、胺苯磺隆、草除灵三者复配后喷施,可以保证对马蹄金草坪杂草的防除效果,又能降低成本.     

Management of newly established field margins on nutrient-rich soil to reduce weed spread and seed rain into adjacent crops

We studied the effect of different ways to establish and to maintain unfertilised field margins on the development of potential weeds and seed dispersal into adjacent crops. Plant communities in field margins either developed spontaneously or were sown with different seed mixtures of grasses and forbs. Margins were mown twice a year and the cuttings were either removed or left in situ. Three years after establishment, the importance of the unsown rhizomatous species Elytrigia repens and Urtica dioica was significantly higher in the unsown community or when cuttings were not removed after mowing. Seed dispersal from the margin into adjacent crops was important in the unsown community during the first year after establishment. Between 82% and 99% of the seeds were disseminated within 4 m from the margin strip. Overall risk of contaminating the adjacent crop with weeds originating from the field margin strip was concentrated within a few metres of the crop edge. In order to minimise the dissemination of weed species and invasion by noxious vegetatively propagated weeds on nutrient‐rich land, it is recommended that field margins are established by sowing and cuttings removed after each cut.     

THE EFFECTS OF MALEIC HYDRAZIDE AND 2,4-DICHLOROPHENOXYACETIC ACID ON ROADSIDE VEGETATION

Summary. Observations have been made on the effects of maleic hydrazide (MH) and 2,4-dichlorophenoxyacetic acid (2,4-D), used singly or as a combined spray, on the vegetation of roadside verges, over a period of 3-4 years (1958-61). Each year, replicate plots were sprayed in spring, and assessments of growth and floristic composition of the vegetation, which was dominated by grasses, were usually made on three occasions. Treatment with MH, used singly, resulted in a general suppression of growth and flowering, particularly of the grasses. Well-marked changes in the composition of the sward were attributable to MH, notably the decline of tufted forms, e.g. Arrhenatherum elatius, Dactylis glomerata , and the rise to dominance of the rhizomatous grasses. These changes were associated with a progressive increase of some dicotyledonous plants, although this was effectively prevented by the combined spray of MH and 2,4-D. Two of the commonest weeds, Anthriscus sylvestris and Heracleum sphondylium , were almost eliminated from plots treated with this combined spray for 3 successive years; a low sward, fairly free from dicotyledons and dominated by Poa rather than Festuca , usually resulted. Treatment with 2,4-D alone, had relatively little effect on growth, flowering and proportion of the different grasses, but there was a reduction in the weed population.
Les effets de l'hydrazide maléique et de l'acide 2,4-dichlorophénoxyacétique sur la végetation au bord d'une route     

THE INTERRELATIONSHIP BETWEEN TILLERS AND RHIZOMES OF POA PRATENSIS L.—AN AUTORADIOGRAPHIC STUDY

Summary. The main shoot or selected tillers of seedling plants of Poa pratensis L. were supplied with ¹⁴CO₂ and the distribution of ¹⁴C-assimilates was followed by autoradiography. The primary tillers were initially supplied with ¹⁴C-assimilates from the main shoot but, once established, became independent of the parental shoot for carbohydrates. Similarly, developing rhizome-tillers were supported by the main shoot and established primary tillers but soon became self-supporting, Defoliation of all the tillers of the plant but one led to the defoliated primary and rhizome tillers being supplied with radiocarbon from the remaining intact shoot. Thus, although the primary tillers and rhizome-tillers in the intact plant appear to be physiologically independent, the entire tiller-rhizome system may be re-integrated after defoliation, allowing assimilate redistribution. P. pratensis may be regarded as a convenient link between the non-weedy herbage grasses which generally lack rhizomes and the weedy rhizomatous grasses typified by Agropyron repens (L.) Beauv.
Etat des relations entre les talles et les rhizomes de Poa pratensis L. Etude autoradiographique     

Effects of different cultivated or weed grasses, grown as pure stands or in combination with wheat, on take-all and its suppression in subsequent wheat crops

Grass species were grown in plots, as pure stands or mixed with wheat, after a sequence of wheat crops in which take-all ( Gaeumannomyces graminis var. tritici ) had developed. Annual brome grasses maintained take-all inoculum in the soil as well as wheat (grown as a continuous sequence), and much better than cultivated species with a perennial habit. Take-all developed more in wheat grown after Anisantha sterilis (barren brome) or Bromus secalinus (rye brome), with or without wheat, than in continuous grass-free wheat in the same year, where take-all decline was apparently occurring. It was equally or more severe, however, in wheat grown after Lolium perenne (rye-grass) or Festuca arundinacea (tall fescue), despite these species having left the least inoculum in the soil. It was most severe in plots where these two grasses had been grown as mixtures with wheat. It is postulated that the presence of these grasses inhibited the development of take-all-suppressive microbiota that had developed in the grass-free wheat crops. The effects of the grasses appeared to be temporary, as amounts of take-all in a second subsequent winter wheat test crop were similar after all treatments. These results have important implications for take-all risk in wheat and, perhaps, other cereal crops grown after grass weed-infested cereals or after set-aside or similar 1-year covers containing weeds or sown grasses, especially in combination with cereal volunteers. They also indicate that grasses might be used experimentally in wheat crop sequences for investigating the mechanisms of suppression of, and conduciveness to, take-all.     

CONTROLLED INTERFERENCE WITH NATURAL POPULATIONS OF PLANTAGO LANCEOLATA, P. MAJOR AND P. MEDIA

Summary. An experiment was made to determine the effect of the removal of grasses on the behaviour of populations of Plantago lanceolata , P. media and P. major in three grassland habitats. Treatments included the addition of seed of all three species to the existing vegetation. The grasses were removed by treatment with 2,2-dichloropropionic acid (dalapon), a herbicide selective against the Gramineae. The chemical appears to be slightly toxic to the Plantago species at the dose used (12 Ib/ac a.e.). The removal of the grasses was followed by a marked increase in the plantain populations shown both in counts of the numbers of plants and seedlings and in increased seed output per unit area. Deliberate sowing of seed into the habitats in autumn resulted in increased numbers of seedlings in the following spring, particularly in those plots where the grasses had been removed. Species of Plantago not occurring naturally in the communities were frequently established by sowing seed, if the grasses had been removed, but not otherwise. The overall results of the experiment suggest that in two of the communities the grasses played an important role in determining the presence or absence of particular Plantagn species and also in controlling the size of the existing plantain populations. The experiment is discussed in the wider context of population control in plants.
Tentative de modification de populations naturelles de Plantago lanceolata, P. major et P. media.