Leaf Area Duration of Oat at High Latitudes

Contribution of leaf area duration (LAD) to grain yield during the short growing season characteristic of northern latitudes may differ from the marked impact it has at lower latitudes. Three experiments (exps) were carried out at Viikki Experimental Farm, University of Helsinki, Finland (60° 13′N) to compare associations between main shoot and tiller LAD with grain yield, yield components and morpho-physiological traits characterizing plant stand structure. This was done using correlation analysis and principal component analysis (PCA) for data from trials conducted during 1993–1995. Exp I included three N fertilizer rates (80, 120, 160 kg N ha^?1), three seeding rates (250, 500, and 750 seeds m^?2), and tall, moderate, semi-dwarf, and dwarf oat lines. Exp II incorporated two N fertilizer rates (80 and 120 kg ha^?1), three seeding rates (400, 600, and 800 seeds m^?2), and naked and hulled oat lines, and exp III, foliar applications of plant growth regulators [control, chlormequat chloride (CCC), and ethephon], and dwarf, naked, and conventional oat lines. LAD for main shoots and tillers [calculated as ∫ LAI d T, where T is cumulated degree days from seedling emergence to yellow ripening (dd °C)] and 12 morpho-physiological traits were measured. Oat was not able to benefit from high main shoot LAD if drought occurred at grain-fill, but in the absence of severe drought or if it occurred at pre-anthesis, high LAD favoured yield formation. Tiller LAD had a negative impact, if any, on grain yield in cases of an inverse relationship between tiller LAD and yield components on main shoots was recorded. Use of low seeding rates resulted in improved ability of total LAD to contribute to dry-matter production, but was not associated with grain yield. Low seeding rates enhanced formation of high tiller LAD, which was not able to compensate for grain yield reduction caused by fewer main shoots. Foliar application of CCC and ethephon tended to increase the proportion of LAD production by tillers at the expense of grain yield, which can be attributed to lower post-anthesis precipitation. Oat types differed in main shoot and tiller LAD. Disadvantageous characteristics of naked oat, such as low single groat weight, were not associated with insufficient main shoot LAD. High tiller LAD in naked lines and the Minnesota-adapted dwarf line that was not associated with high tiller grain yield in naked lines, in particular, indicates that tiller growth was enhanced at the expense of grain yield production. Application of N fertilizer at various rates did not have any effect on LAD.     

水稻高光效宽窄行栽培试验研究

引进示范了水稻高光效宽窄行栽培技术。为提高水稻的有效分蘖率,从而提高产量,提供了有力的技术支撑。同时根据水稻的不同品种,出穗压圈后,其垄间交叉,重叠,相互遮阴的程度,提出了改进宽窄行距的建议。     

分蘖期水分胁迫对水稻生长发育及产量的影响

采用盆栽方法研究了分蘖期水分胁迫对水稻生长发育及产量的影响。结果表明：分蘖期水分胁迫对水稻分蘖数、叶面积指数(LAI)和株高都有较大的影响,影响的严重程度与水分胁迫水平相一致。处理组水稻平均分蘖数、LAI、株高分别比对照低28％、26．6％、14．4％。由于分蘖期水分胁迫抑制了水稻的生长发育,影响了水稻分蘖的发生与生长,最终导致单位面积的有效穗不足、穗粒数低而严重影响产量,处理组平均产量比对照低29．5％。     

氮素水平对冬小麦分蘖期某些含氮化合物及生物量的影响

利用水培研究了氮素水平对冬小麦分蘖期某些含氮化合物及生物量的影响。结果表明,随着氮素水平提高,小麦叶片、根系硝态氮含量及可溶性蛋白含量升高;根系铵态氮含量在5和15mmol/L时最高,二者之间差异不显著;叶片铵态氮含量在5和25mmol/L时最高;单位鲜重的叶绿素含量在5mmol/L时最高,但单株叶绿素含量随供氮水平的升高而升高;在氮素水平为15mmol/L时,植株含水量、叶面积、地上和根系鲜重、干重均最大。     

水稻中位蘖成穗与高产利用研究

就同期播种和同期移栽条件下，插秧至分蘖初期两种不同水层秧苗的分蘖与成德规律进行了分析。结果表明，插秧至分蘖初期采取适当的水层处理，能有效地抑制水稻主茎下部分蘖的发生，并淹死秧田所带分蘖，使开始发生分蘖的叶位上移，防止因下部蘖位发生分蘖对中部优势蘖位的不良影响。集中利用主茎中上部有效蘖位发生分蘖与成穗。在单位面积上收获穗数相近的条件下，使平均每穗粒数显著增加，从而使产量大幅度提高。前控结合后控，集中利用主茎中部的分蘖，发挥蘖位优势具有更大的增产潜力。     

双季稻早季直播与晚季再生施肥技术研究

【目的】改传统的水稻双季种植为早季直播 + 晚季再生新型种植模式,通过应用早季直播稻一次性施肥技术与再生稻喷施促根促蘖液肥 2 项关键技术,拟解决再生稻穗数少、穗形小导致产量低的问题,实现产量与生产效益的提高。【方法】采用盆栽试验探讨一次性施肥对水稻根系、产量及其构成因素的影响,采用田间试验研究早季直播稻一次性施肥与再生稻喷施促根促蘖液肥对两季水稻产量、再生稻发育以及整体效益的影响。【结果】一次性施肥的水稻分蘖早、分蘖数略高于分次施肥,增加了水稻成穗数,且有利于培育水稻庞大根系。一次性施肥处理的水稻产量比等养分的分次施肥处理依次增产 3.7%、8.7% 和 31.3%,说明一次性施肥方式增产显著。一次性施用 600、750 kg/hm2 控释肥处理并结合喷施两种促根促蘖液肥,水稻穗数、穗粒数均高于对照,说明具有促穗增加穗粒数的效果,且促根促蘖液肥Ⅰ效果较好。3 种施肥量结合配施促根促蘖液肥处理的年效益均显著高于双季稻常规种植,其中,750、900 kg/hm2 控释肥处理结合促根促蘖液肥年效益分别提高6 859、8 291 元 /hm2。【结论】一次性施肥技术具有提高水稻产量的效果,促根促蘖液肥Ⅰ可有效增加水稻分蘖,双季稻早季直播稻采用一次性施肥技术、再生稻喷施促根促蘖液肥效益比常规种植能明显提高。     

空育131水稻分蘖消长与叶龄进程的调查分析

利用6a的时间,对空育131的生育进程、分蘖消长规律、出叶周期以及产量性状进行调查分析,比较详细地描述了该品种在上述方面的一般性规律,进而明确了穗分化的两个关键时期,提出了该品种高产的主攻方向。     

水的垂直渗透对水稻生长发育的影响研究

通过研究水的垂直渗透对水稻返青、水稻分蘖、水稻产量的影响,提出通过完善排水工程、设施,定期深耕田地,改善土壤渗透性,为水稻高产奠定基础。     

水稻品种分蘖特性对产量影响分析

分析了不同肥力水平条件下水稻品种分蘖特性对产量的影响．结果表明，１）穗数型品种分蘖力强，高肥栽培时单茎增多、叶面积增大、茎秆细弱、倒伏、结实率降低，不适于高产再高产的要求；２）高肥栽培时，分蘖力偏弱但有效分蘖期长，在较长分蘖期内逐渐产生分蘖的品种类型，可协调穗数、穗粒数和结实率的矛盾，从而获得高产；３）具有矮秆、中等分蘖能力、有效分蘖期长、有效分蘖率高、叶长而直立的穗重型品种，可协调高肥栽培时群体和个体的矛盾，有望实现超高产．     

龙须草分蘖规律初探

龙须草分蘖特性与禾本科多数植物类似,但是其分蘖能力极强,一颗种子苗一年可分百蘖以上。龙须草分蘖的多寡、快慢与品种、播种期、移栽期、温度、水分、光照、坡向和养分等因素有关,其中温度和水分是主导因子。龙须草耐旱性虽强,但以70％左右的田间持水量对分蘖最为有利。水热同步的夏季为龙须草分蘖高峰期。