不同氮水平下多效唑对食用型甘薯光合和淀粉积累的影响

在大田条件下,以北京553为试验材料,设置施低氮(N 120 kg hm^–2)和施高氮(N 240 kg hm^–2) 2个处理,每个处理下设置3个多效唑喷施浓度,研究不同施氮水平下喷施多效唑对食用甘薯光合特性和块根淀粉积累的影响。结果表明, 增施氮肥能够提高叶片叶绿素含量和光合速率,但减少干物质在块根中的分配率,降低块根淀粉积累速率,显著降低了单薯重、淀粉产量和鲜薯产量,降幅分别为8.0%、30.7%和20.5%;喷施多效唑可以提高叶片叶绿素含量和光合速率,促进碳水化合物向块根的运转,提高干物质在块根中的分配,提高淀粉积累速率,显著增加单薯重、淀粉产量和鲜薯产量,平均增幅分别为18.6%、32.5%和46.1%。说明在高氮条件下喷施多效唑对甘薯块根淀粉积累和产量的提高具有明显的调节作用。     

优化施肥对鲜食型甘薯产量、养分利用及土壤性质的影响

为实现鲜食型甘薯提质增效,本试验以‘烟薯25’为供试品种,设置不施肥、习惯施肥、优化施肥、优化施肥+有机肥4个不同处理,研究不同施肥处理对土壤养分及‘烟薯25’的产量效应、干物质分配、氮磷钾吸收利用情况。结果表明：施肥措施可以有效提高土壤养分含量,优化施肥+有机肥处理显著提升‘烟薯25’的单薯重和鲜薯产量,促进生物产量向甘薯块根转运及干物质向块根分配,提高茎叶、块根及总生物量的氮、磷、钾积累量,且氮、钾的产块根效率和收获指数较习惯施肥均有显著性提高。     

改善土壤通气性促进甘薯源库间光合产物运转的原因解析

为了明确土壤通气性对甘薯源库间光合产物运转的调控机制,本研究以淀粉型品种商薯19和济徐23为试验材料,设置疏松、对照和紧实3个处理进行大田试验,研究结果表明,与对照处理相比,疏松处理显著提高2个品种的块根产量和经济系数, 2年平均增幅分别为27.03%～38.74%和6.30%～13.05%,紧实处理则显著降低2个品种的块根产量和经济系数, 2年平均降幅分别为17.87%～15.92%和10.83%～15.63%。功能叶13C标记结果显示,疏松处理显著提高块根中光合产物的输入效率。疏松处理显著提高块根中蔗糖和淀粉含量,显著降低地上部器官中淀粉含量和茎中尤其是茎的中下部中蔗糖含量;紧实处理则显著降低块根中蔗糖和淀粉含量,而显著提高地上部器官蔗糖和淀粉含量,且茎中下部蔗糖含量增幅较大。疏松处理显著降低50～150d茎基部与茎顶部间和茎基部与块根间的蔗糖含量差;紧实处理则显著提高茎基部与茎顶部间和茎基部与块根间的蔗糖含量差,且茎基部与块根间蔗糖含量差的变幅大于茎基部与茎顶部间的蔗糖含量差。相关分析表明,茎基部与块根间、茎基部与茎顶部间蔗糖含量差与块根蔗糖和淀粉含量呈极显著负相关。说明改善土壤通气性可促进茎基部光合产物向块根的运转,提高块根中碳水化合物含量,增加块根产量。     

植物生长调节剂对甘薯产量和激素含量的影响

为了探讨植物生长调节剂对甘薯产量和激素含量的影响,以济薯18、徐薯18和商薯0110为试验材料,在开始进入块根膨大期时(移栽后第35天),叶面喷施矮壮素·DA-6合剂和烯效唑,观察植物生长调节剂对不同生长类型甘薯的产量、光合作用和叶片、块根中的激素含量的影响。结果表明,植物生长调节剂处理促进同化物向根部的转运,提高了块根的产量。其中每hm2喷施1 500 m L矮壮素·DA-6合剂处理显著提高了3个品种的产量,225 g烯效唑处理显著提高了济薯18和徐薯18的产量。调节剂处理对不同类型甘薯光合作用的影响不同,矮壮素·DA-6合剂处理显著提高了徐薯18的光合速率,而对济薯18和商薯0110的光合速率的提高没有达到显著水平,烯效唑处理对甘薯叶片的光合作用没有显著影响。烯效唑处理降低了3个甘薯品种的叶片IAA含量,显著降低了济薯18膨大中期的GA3和叶片ZR含量,降低了徐薯18膨大后期的块根ZR和ABA含量;增加了济薯18和徐薯18膨大中、后期的叶片ABA含量、膨大前、中期块根IAA含量以及整个商薯0110膨大期的块根IAA含量。矮壮素o DA-6合剂处理显著降低了济薯18膨大中期的叶片IAA、膨大后期的块根和叶片ZR含量,降低了徐薯18膨大前期叶片IAA、ZR、ABA、块根ZR含量以及降低了商薯0110膨大前期的叶片GA3和后期的ZR含量;增加了济薯18膨大前期的块根ABA、GA3、叶片ZR、中期的叶片ABA和整个膨大期的块根IAA含量,增加徐薯18膨大前期的叶片ZR、中期的块根GA3和ZR含量、叶片IAA、ABA、后期的块根IAA含量,增加了商薯0110膨大期的块根ZR、ABA、中期的叶片ZR、后期的叶片GA含量。植物生长调节剂处理部分改变了甘薯内源激素的变化动态,促进了地上部同化物向块根的转运,提高了甘薯的块根产量,植物生长调节剂对甘薯光合作用的影响因品种类型而异,并不是影响甘薯块根产量的主要因素。     

栽插方式和密度对鲜食型甘薯品种干物质积累分配、块根产量及品质的影响

为了确定鲁中丘陵薄地鲜食型甘薯适宜的栽插方式和密度,在大田条件下,以济薯26(J26)和龙薯9号(L9)为供试品种,每个品种设置直栽(S)和水平栽(H) 2种栽插方式,各栽插方式下设置不同栽插密度37 500(D1),52 500(D2),67 500株/hm~2(D3),研究了不同栽插方式和密度对鲜食型甘薯干物质积累分配、产量和品质的影响。结果表明,增加密度可提高两品种生长中后期植株干物质积累量,显著降低相同栽插方式下济薯26生长中期侧枝叶的干物质分配比例。相同栽插方式下,D2处理可降低龙薯9号生长后期侧枝茎干物质分配比例,并显著提高两品种生长中期的块根干物质分配比例。直栽方式下,D2和D3处理显著提高济薯26生长后期块根干物质分配比例。相同栽插方式下,D2和D3处理显著提高两品种块根可溶性糖含量和淀粉含量,D2处理可显著提高两品种块根产量。与直栽相比,水平栽显著提高济薯26生长前期D2处理和后期D2和D3处理下、龙薯9号生长中期相同密度下的植株干物质积累量;有利于提高济薯26 D1处理下、龙薯9号各密度下的块根可溶性糖含量,提高两品种单株薯重和块根产量。综合考虑产量和品质,水平栽+D2处理是本试验条件下的最优处理组合。     

不同产量水平甘薯品种光合产物分配差异及其原因

选取我国北方薯区主栽的食用型甘薯品种龙薯9号、红香蕉、泰中6号、苏薯8号、遗字138和北京553,于2011—2012年2个生长季在山东农业大学农学试验站进行大田试验,研究不同产量水平甘薯品种光合产物的分配差异及其原因。在甘薯主要生长时期测定茎蔓各部位蔗糖含量和基部茎粗、在块根膨大过程中对功能叶进行13C标记,探索不同品种13C同化物分配特点,同时研究上述项目与收获指数和块根产量的关系。结果表明,高产品种龙薯9号、红香蕉、泰中6号和苏薯8号产块根均在60 t hm–2左右,而中、低产品种遗字138和北京553产块根在50 t hm–2以下。高产品种的收获指数显著高于中、低产品种。在块根膨大前期高产品种的块根成为光合产物的分配中心,而中、低产品种的块根则在块根膨大后期成为分配中心;在块根膨大前、中期,高产品种13C同化物在块根中的分配比例显著高于中、低产品种,即高产品种光合产物由功能叶向块根的转运能力强于中、低产品种。供试品种茎蔓基部的蔗糖含量均高于顶部,且中、低产品种的蔗糖浓度差大于高产品种;随着甘薯生长发育,中、低产品种茎蔓基部增粗速率高于高产品种。相关分析表明,块根产量与收获指数呈极显著正相关(r=0.98**,2011;r=0.93**,2012);块根13C分配率与块根产量和收获指数均呈显著正相关(0.87*和0.91**,2011;0.92**和0.99**,2012);生长中后期,基部茎粗与块根产量和收获指数均呈显著负相关(–0.78*和–0.83*;–0.88**和–0.95**)。块根成为光合产物分配中心的时间早、光合产物由功能叶向块根的转运能力强是高产品种收获指数显著提高的主要原因,而中、低产品种光合产物由叶片向块根转运能力差的主要原因是块根中光合产物卸载不畅。     

甘薯发根分枝期适宜土壤水分促进块根糖供应和块根形成的研究

为探讨土壤水分对甘薯块根形成的影响及其与块根数量和整齐度的关系。选用鲜食型甘薯品种烟薯25作为试验材料,在发根分枝期设置50%±5%(W50)、60%±5%(W60)、70%±5%(W70)、80%±5%(W80)、90%±5%(W90) 5个土壤相对含水量水平,通过2年田间试验,研究了土壤水分对甘薯潜在块根中碳水化合物含量及其代谢相关酶活性及收获期块根数量、整齐度和产量的影响。结果表明,甘薯潜在块根中蔗糖、葡萄糖和果糖含量以及蔗糖转化酶活性,栽植后10～35d,W70处理均显著高于其他处理。甘薯潜在块根中蔗糖合酶活性和淀粉含量,栽植后10～25d,W70处理显著低于其他处理;栽植后30～35 d, W70处理显著高于其他处理。W70处理的单株结薯数和块根产量分别较其他处理提高14%～120%和22%～122%、单薯重的变异系数较其他处理降低9%～34%。甘薯发根分枝期土壤相对含水量70%有利于促进块根形成,增加收获期单株结薯数、单薯重和块根产量,改善块根商品品质。     

氮肥施用量对不同紫甘薯品种产量和氮素效率的影响

选取紫甘薯品种浙紫1号、宁紫2号和紫菁2号,设置3个施氮处理,即0 (N0)、75 (N1)和150 (N2) kg hm^–2纯氮,于2013-2014年2个生长季在青岛农业大学现代农业科技示范园进行大田试验,研究不同氮肥用量对块根产量、干物质累积速率、氮素累积量及氮素效率的影响。结果表明,施用氮肥不同程度地降低了浙紫1号和紫菁2号的薯块产量,其中,浙紫1号的N1、N2处理分别较N0处理降低12.64%和13.32%,紫菁2号分别降低3.94%和29.06%;宁紫2号N1处理产量略高于N0处理,两年分别较N0处理提高8.5%和3.4%,而N2处理块根产量显著低于N0处理。茎蔓生物量和氮素累积量随着施氮量的增加而增加,而收获指数、氮素收获指数和氮素利用效率逐渐降低。第1年N1、N2处理的茎蔓干物质累积量分别较N0处理提高2.7%~20%和12.3%~36.4%,第2年分别提高12.6%~51.9%和28.7%~85.5%。相关分析表明,块根产量与氮素效率各指标均呈显著或极显著正相关;而茎蔓生物量与收获指数、氮素收获指数及氮肥利用效率均呈极显著负相关(r = –0.615^**, –0.704^**, –0.663^**)。肥沃土壤上施用氮肥会造成浙紫1号和紫菁2号的茎蔓旺长,光合产物向薯块转运比例降低,导致源库比例不协调,块根产量下降。宁紫2号对氮肥的需求相对较高,施用氮肥75 kg hm^–2时鲜薯产量提高,而施氮量过高时薯块产量降低。因此,紫甘薯在含氮量较高的肥沃土壤上种植时,对氮肥的需求量较低,茎蔓和薯块的协调生长是提高块根产量和氮素利用效率的保障。     

施钾量对紫甘薯产量及养分利用的影响

为了探明不同施钾量对紫甘薯产量及养分利用的影响,为紫甘薯合理施用钾肥提供理论与实践依据。采用随机区组试验设计、田间试验与化学分析相结合的方法,研究不同施钾量对低肥力土壤上紫甘薯干物质积累、产量及其构成因子、氮磷钾素积累、钾素利用效率的影响。结果表明,在甘薯整个生育期,施钾处理紫甘薯块根干物质积累量高于K0处理,在施钾量为180 kg/hm~2时块根干物质积累量达到最大值。施钾可提高地下部干物质分配比率,增加单株结薯数和单块薯质量,从而提高紫甘薯产量,以施钾量为180 kg/hm~2时增产幅度最大,与不施钾处理相比,2016,2017年分别增产20. 78%,26. 19%,且差异显著(P 0. 05)。与K0处理相比,施钾可促进紫甘薯对氮素和磷素的吸收,并显著提高收获期整株氮磷累积量,以K3处理增幅最大;块根和整株氮累积量分别增加75. 38%,65. 75%,磷累积量分别增加45. 24%,60. 28%,且差异显著(P 0. 05)。施钾处理显著提高钾肥表观利用率和农学利用率,与K0处理相比,K3处理表观利用率和农学利用率分别增加了47. 82百分点,158. 11%,且差异显著(P 0. 05)。因此,在该试验条件下,紫甘薯最适施钾量为180 kg/hm~2。     

不同施磷量对鲜食型甘薯产量及磷素吸收的影响

采用田间试验的方法,设置了6个磷水平(0,37.5,75.0,112.5,150.0,187.5kg/hm²),研究不同施磷量对鲜食型甘薯产量、干物质积累和磷素积累的影响。结果表明,施磷能够显著增加甘薯产量并提高商品薯率,当施磷量为P205112.5kg/hm²时增产幅度最大。施磷水平对甘薯干物质积累与分配有显著影响,在甘薯各生长时期施磷条件下块根干物质积累量和积累速率整体上均显著高于不施磷处理(P<0.05),同时施磷还提高了地下部干物质分配比率,促进了块根产量的形成。施用磷肥可以显著提高甘薯对磷素的积累,随着施磷量的增加,甘薯植株的磷积累量呈现增加趋势。     

耕层构造对土壤三相比和春玉米根系形态的影响

建立适宜耕层构造是解决旱作农田耕层"浅"、"实"、"少"问题的重要技术措施之一,对北方旱作农田具有重要意义。在国家农业环境阜新科学观测实验站利用长期定位试验,设置虚实并存耕层(furrow loose and ridge compaction plough layer, FLRC)、全虚耕层(all loose plough layer, AL)、全实耕层(all compaction plough layer, AC)、上虚下实耕层(up loose and down compaction plough layer, ULDC, CK) 4种处理,研究耕层构造对土壤三相比和春玉米根系形态的影响。耕层构造定位试验始于2009年,本文利用2015年和2016年数据分析果表明,虚实并存耕层能够优化土壤三相比(P 0.05),春玉米播种前0～10 cm土壤三相比以全实耕层构造为宜, 10～30 cm以虚实并存和全虚耕层构造为宜;春玉米收获后20～30 cm土壤三相比的虚实并存和全虚耕层构造优于上虚下实耕层和全实耕层构造。虚实并存耕层构造能够增加春玉米吐丝期根重密度、根长密度、根表面积密度和根体积密度(P 0.05);其中春玉米根重密度增幅7.47%～97.09%,根长密度增幅6.62%～112.04%,根表面积密度增幅9.80%～125.07%,根体积密度增幅40.11%～151.97%。虚实并存耕层可以显著增加春玉米籽粒产量(P0.05),增幅18.19%～34.86%,主要原因是行粒数的显著提高和秃尖的降低;还增加群体生物产量(P 0.05),增幅5.18%～11.30%;和提高收获指数(P 0.05)。综合分析认为,虚实并存耕层是改善土壤三相结构和优化春玉米根系形态的最优耕层结构,在辽西旱作农田合理耕层构建中具有一定的应用价值。     

不同施钾量条件下甘薯块根形成的内源激素变化及其与块根数量的关系

In order to explore the changes of endogenous hormones on storage root formation and its relationship with storage root number under different potassium application rates of sweet potato root, sweet potato varieties ‘Yanshu 25’ and ‘Beijing 553’ with significant differences in storage root number were used as experimental materials, potassium oxide (K₂O) was used as fertilizer, and four potassium fertilizer gradients of 0 (K0), 120 (K2), 240 (K3), and 360 kg hm^-2 (K4) were set. The effects of different potassium application rates on the contents of endogenous hormones, the activity of related metabolic enzymes, the number of storage root and root evenness in swelling roots of sweet potato during root formation and harvest stage were studied. Compared with the treatment without potassium fertilizer (K0), the application of potassium fertilizer decreased the enzyme activities of indoleacetic acid oxidase (IAAO) and peroxidase (POD), increased the content of indole-3-acetic acid (IAA), increased the content of zeatin riboside (ZR) and decreased the content of gibberellins (GA₃). Potassium application enhanced the activity of primary cambium and promoted the differentiation from adventitious root to storage root by regulating the content of endogenous hormones in swelling roots of sweet potato. Compared with the control, the application of potash fertilizer significantly increased the number and weight of storage roots per plant and root yield of ‘Yanshu 25’ and ‘Beijing 553’. The number of storage roots per plant of ‘Yanshu 25’ and ‘Beijing 553’ increased by 3.16%-25.40% and 3.85%-33.11%, respectively, and the yield increased by 4.22%-17.31% and 3.94%-18.45%, respectively. Compared with the potassium application treatments of the two varieties, the K2 treatment had the highest storage roots number per plant, the highest weight and yield of storage roots, with the best root evenness.     

黑土机械压实对土壤结构和甜菜产量的影响

黑土机械压实是由于机械化作业引起的土壤结构破坏,导致土壤质量下降。通过对土壤孔隙比、土壤孔隙度比、土壤透气性、渗透率等指标的分析,明确了土壤压实积累区变化特征总体上表现为,随着机械压实次数的增加,土壤隙比和土壤孔隙度比均减小,通气性变差,土壤雨水入渗率降低,影响区域以5-10cm耕层土壤为最大,拐点在10cm处,对深层土壤的影响减小。土壤压实给甜菜生长造成不利影响,与对照比甜菜块根直径小6.67%-16.08%,甜菜块根长度短1.96%-17.65%,块根产量减产5.81%-24.13%,含糖率降低0.49-0.81度,糖产量降低4.73%-27.03%,碾压次数越多对甜菜产质量的降低作用越显著。     

不同膜上遮挡措施对旱地玉米土壤理化性状及产量的影响

Aiming at the phenomenon of premature senescence of plants under long-term maize plastic film mulching in rainfed and arid regions in Northwest China, adding cooling measures on mulched maize were taken to study the effects of soil temperature change on maize yield formation and analysis the changes of soil physical and chemical properties in topsoil of maize from the perspective of never changing the water conserving function of plastic film, which would provide the theoretical reference for the analysis of the early senescence in the later growth stage of ordinary plastic film maize. This experiment design using Shaandan 609 (SD 609) as tested materials, based on a 2-year field experiment, compared with the effects of three modes, ordinary plastic film mulch + black sunshade net (A), ordinary plastic film mulch + straw (B) and ordinary plastic film mulch (C) on soil temperature, soil nutrients, dry matter mass accumulation yield and water and fertilizer use efficiency in yield. The results were as follows: (1) Adding coverings on plastic film mulching (black sunshade net, straw) can effectively decrease the soil temperature and compactness, especially early stage of maize growth. (2) Compared with the control treatment C, cooling treatment A and treatment B significantly increased the content of organic matter, total nitrogen and total potassium in the later stage of maize growth, and the average partial fertilizer productivity increased by 7.24% and 6.97%, respectively. (3) Cooling treatments can delay the attenuation of green leaf area in the later stage of maize growth, improve the accumulation rate of dry matter and increase the kernel weight of maize. Compared with treatment C, the 2-year average maize yields of cooling treatment A and treatment B were increased by 6.39% and 5.93% and the average water use efficiency by 8.17% and 7.67%, respectively. In rainfed and arid regions in Northwest China, properly reducing the temperature under the film of mulched maize are helpful to improve soil physical and chemical properties, promote the accumulation of dry matter and the formation of yield and improve the high utilization efficiency of fertilizer and water.     

Factors Affecting Growth and Harvest Index in Pea (Pisum sativum L.) Varieties Differing in Time of Flowering and Maturity

Three varieties of Pea ( Pimm sativum L.) viz. EC33866 (early), P-116 (medium) and T-163 (late), differing in their flowering and maturity times, were taken for this study. The early variety recorded lower dry matter, CO₂ exchange rate and lower yield. The harvest index (HI) was the highest (44 %) in this variety. Though medium and late varieties did not differ significantly in dry matter accumulation and pod yield, they differed in their HI. The HI in the medium variety is 42 % but in the late variety it is only 36%.
The late variety maintained high leaf area, leaf dry weight, high shoot/root, shoot/nodule and root/nodule ratios, increased nodule dry weight and maximum glycolate oxidase activity. But acetylene reduction activity was low, and the harvest index was lowest. On the other hand, in the early variety the dry matter accumulation was lowest but HI was highest. The major reasons for high HI in this variety were translocation of photosynthates to reproductive organs and lower photorespiration as indicated by low glycolate oxidase activity.     

Effect of Homogeneous and Heterogeneous Soil Compaction on Shoot and Root Growth of Field Bean and Soybean

The study was done to observe the effects of soil compaction on field bean and soybean growth in greenhouse. Plastic cylindrical tubes of 58 cm height and 12 cm diameter were filled with silty loam soil with three bulk densities i.e., low (1.25 g/cm³), medium (1.45 g/cm³) and high (1.65 g/cm³) either separately or in combination of low/medium (level 1), low/high (level 2) and medium/high (level 3) as top and sub-soil densities.
General effect of compaction was a reduction in shoot and root growth and in yield of both the legumes; probable reason seemed to be mechanical impedance. At homogeneous compaction throughout the soil profile high bulk density decreased the root dry matter from 6 to 32 % and total root length from 30 to 57% but total root volume was not much affected due to thickening of the roots. From 4 to 31% reductions were also observed in shoot dry matter. Increase in only subsoil density from medium to high (level 2) decreased shoot and root dry matters (8 to 36% and 16 to 39%, respectively) but not the total root length. Plant growth was more hampered when both top and subsoil densities were increased (level 3) but the total root length was not highly affected in the upper (0 to 20 cm) and middle (20 to 40 cm) layer.     

Effect of soil drought on growth and yield of maize (Zea mays L.) hybrids grown under compacted soil

In this study, we examined responses of maize hybrids differing in susceptibility to soil compaction and drought in the case of their separate or combined action. We ran field and greenhouse experiments and determined effects on grain yield, biomass, weight of 1000 grains, shoot and roots dry matter (DM), shoot-to-roots ratio, harvest index, plant height, emergence index, leaf area and greening and root number and length. Individual and combined effects of both stresses were observed in the field and greenhouse. Compared with plants growing in loose soil and optimal irrigation (LI), the resistant hybrids in treatments HI, LD and HD showed a smaller reduction in GY, BY, S, R, R_N and R_L than the sensitive. In both groups, stress influence on HA, W-1000, LA and SPAD was smaller and the differences were insignificant. Compared with LI treatment, the roots of LD, HI and HD increased their DM, number and length in the upper level of the soil profile and the number of roots developed at 0–30° and 30–60° in relation to the root main axis. Analysis of those traits in the hybrids resistant and sensitive to both stress factors enabled to explain a defence response. Our study demonstrated that soil compaction and soil drought, which usually occurs simultaneously, caused significant changes in components of plant yield and showed plant plasticity in response to environmental factors under natural conditions.