11%精甲·咯·嘧菌悬浮种衣剂对棉花立枯病的防治效果

为了明确11%（质量分数，下同）精甲·咯·嘧菌悬浮种衣剂对棉花立枯病的田间防治效果，以3种单剂即350 g·L^－1精甲霜灵种子处理乳剂、10%嘧菌酯悬浮种衣剂和25 g·L^－1咯菌腈悬浮种衣剂的高、中、低常用剂量作为药剂对照，以清水处理为空白对照，开展11%精甲·咯·嘧菌悬浮种衣剂制剂高（4.4 g·kg^－1）、中（3.3 g·kg^－1）、低（2.2 g·kg^－1）用量的种子包衣处理防治棉花立枯病试验。结果表明：4种杀菌剂3个剂量的防治效果表现为11%精甲·咯·嘧菌悬浮种衣剂＞25 g·L^－1咯菌腈悬浮种衣剂＞10%嘧菌酯悬浮种衣剂＞350 g·L^－1精甲霜灵种子处理乳剂，其中11%精甲·咯·嘧菌悬浮种衣剂在高剂量时防治效果达到84.03%；各处理对棉苗生长安全。以上结果可为应用该类药剂防治棉花立枯病提供科学依据。     

戊唑醇、二甲戊灵和氟节胺的棉花化学打顶效果

为研究开发新型、高效、安全的棉花化学打顶剂,筛选适于棉花的化学打顶剂配方,选择杀菌剂戊唑醇、除草剂二甲戊灵和抑芽剂氟节胺3种药剂,于2020年在河南安阳进行棉花化学打顶试验,研究其化学打顶效果。结果表明：430 g·L^－1戊唑醇悬浮剂（SC）258 g·hm^－2（有效成分用量,下同）＋330 g·L^－1二甲戊灵乳油（EC）990 g·hm^－2＋25%（质量分数,下同）氟节胺SC 300 g·hm^－2混配处理抑制棉花株高和增产效果最佳,可以达到人工打顶的效果;其次为430 g·L^－1戊唑醇SC 516 g·hm^－2＋25%氟节胺SC 300 g·hm^－2处理;而330 g·L^－1二甲戊灵EC 1 485 g·hm^－2＋25%氟节胺SC 300 g·hm^－2处理和25%氟节胺SC 500 g·hm^－2单剂处理可在一定程度上提高棉花产量,但对棉花的打顶效果远不及人工打顶,仍须优化配方和确定合适剂量。因此,在本研究区宜用430 g·L^－1戊唑醇SC 258 g·hm^－2＋330 g·L^－1二甲戊灵EC 990 g·hm^－2＋25%氟节胺SC 300 g·hm^－2或430 g·L^－1戊唑醇SC 516 g·hm^－2＋25%氟节胺SC  300 g·hm^－2进行棉花化学打顶来代替传统人工打顶。     

外源褪黑素对镉胁迫下棉苗生长及光合特征的影响

镉抑制作物的光合作用，降低光合产物积累，影响幼苗发育。褪黑素能缓解镉胁迫对棉花光合作用抑制，但其具体效应尚不明确。2021年在河北农业大学作物生长调控实验室的智能温室内以农大棉601为试验材料，开展不同浓度褪黑素（melatonin, MT）缓解镉胁迫（75 μmol·L^－1的CdCl2溶液）下棉苗光合及发育抑制的效果试验。结果表明：在镉胁迫（75 μmol·L^－1）下喷施一定浓度的MT后，尤其是浓度为50 μmol·L^－1时，棉苗的叶绿素含量（SPAD值）、净光合速率、气孔导度和蒸腾速率较镉胁迫处理显著提高。但是，随着MT浓度的增高，其对棉苗镉胁迫的缓解作用表现为先升高再下降的趋势，且高浓度（200 μmol·L^－1）MT处理对缓解棉苗镉胁迫无显著效果。本研究条件下，50 μmol·L^－1 MT缓解棉苗镉胁迫的效果最佳。据此初步认为，施用适宜浓度的MT能有效地改善镉胁迫条件下棉苗的生长状况，增强其光合作用能力、根系发育，从而提高棉花耐镉性。     

适乐时等农药处理种子防治棉花苗期病害效果

为筛选防治棉花苗病的理想药剂,2018年进行了不同药剂包衣或拌种防治棉花苗期病害试验。结果显示：7种杀菌剂中以2.5%（质量分数）适乐时悬浮种衣剂包衣效果最佳,防治效果达到84.8%～86.3%,显著优于其他参试药剂,且对棉花幼苗安全无害;450 g·L^－1克菌丹悬浮种衣剂和400 g·L^－1卫福悬浮种衣剂包衣防治效果也较好。找出了适合新野县防治棉花苗期病害的药剂和使用剂量,可为其科学防治提供依据。     

三种浸种剂对Na2SO4胁迫下小麦种子萌发期耐盐性的影响

为了解黄腐酸、褪黑素、水杨酸三种浸种剂对硫酸盐胁迫下小麦种子萌发期耐盐性的调节效应,分别采用不同浓度的黄腐酸(0.5、1.0和1.5 g·L^-1)、褪黑素(0.01、0.05和0.10 mmol·L^-1)、水杨酸(0.1、0.5和1.0 mmol·L^-1)对小麦进行浸种处理,随后与未处理的小麦种子一并采用100 mmol·L^-1 Na₂SO₄溶液培养,测定各处理下小麦种子萌发期的生长生理指标,并通过主成分分析综合评价其耐盐性。结果表明,0.5～1.5 g·L^-1的黄腐酸、0.01～0.10 mmol·L^-1褪黑素、0.1～0.5 mmol·L^-1水杨酸浸种均提升了小麦根系活力、体内抗氧化酶活性,降低了小麦体内超氧阴离子自由基■产生速率及丙二醛(MDA)含量,缓解了盐分对小麦种子萌发的胁迫程度,增强了小麦种子萌发期的耐盐性,促进了小麦的萌发生长。其中,1.5 g·L^-1的...     

外源一氧化氮对干旱和盐胁迫下棉种萌发的影响

探明外源一氧化氮（Nitric oxide,NO）对干旱和盐胁迫下棉种萌发能力的效应,可为提高棉花抗逆性提供理论依据。以国欣棉3号为试验材料,设置干旱和盐胁迫处理,其中干旱胁迫采用不同质量浓度（0,25,50,100,200 g·L^－1）的PEG（聚乙二醇,Polyethylene glycol）模拟,盐胁迫由不同浓度（0,150,200,250和350 mmol·L^－1）的NaCl模拟。结果表明,干旱胁迫和盐胁迫均抑制棉种萌发。在25～100 g·L^－1 PEG或150～350 mmol·L^－1 NaCl胁迫下,外源NO能提高发芽率,显著提高棉种发芽势、发芽指数和活力指数,并在一定程度上增强超氧化物歧化酶活力,提高可溶性蛋白的含量;200 g·L^－1 PEG处理,NO会降低以上指标。本研究认为,在低程度干旱胁迫（25～100 g·L^－1 PEG）及盐胁迫（150～350 mmol·L^－1 NaCl）下,外源NO能够缓解其对棉种的损伤,提高棉种的萌发能力。     

保美乐对棉花提质增产示范试验效果评价

通过试验示范,验证保美乐[0.01%（质量分数,下同）芸薹素内酯可溶液剂＋250 g·L^－1吡唑醚菌酯乳油＋63%增产助剂]对新疆生产建设兵团棉花生长发育、抗病、增产、促早熟和改善棉花纤维品质等方面的效果。结果表明：保美乐处理的棉花株高高于对照,茎粗（直径）略低于对照;对黄萎病防治效果达33.25%;单株果枝数较对照增加0.59,单株结铃数较对照增加0.78,铃重较对照增加0.46 g;667 m²籽棉产量为484.55 kg,较对照增产19.88%;吐絮期较对照提前3 d;棉纤维长度整齐度指数、断裂比强度、马克隆值较对照分别提高0.5百分点、1.2 cN·tex^－1、0.2,上半部平均长度、断裂伸长率分别降低0.7 mm、0.4百分点。可见,保美乐对促进棉花生长发育、提高棉花产量和抗病性有较好的效果,可促进棉花早熟、对部分棉花纤维品质指标提升有一定作用。     

40%噻虫嗪·吡唑醚菌酯·萎锈灵悬浮种衣剂对棉花立枯病的防治效果

以250 g·L^－1吡唑醚菌酯乳油和50%（质量分数，下同）多菌灵可湿性粉剂为对照药剂，设置40%噻虫嗪·吡唑醚菌酯·萎锈灵悬浮种衣剂3个不同剂量处理，评价其对棉花立枯病的防治效果。2年试验结果表明，40%噻虫嗪·吡唑醚菌酯·萎锈灵悬浮种衣剂高剂量处理（每100 kg种子用有效成分400 g）对棉花立枯病的防治效果分别为89.9%和86.3%，极显著高于2个对照药剂处理，且该制剂对种子萌发、出苗率、苗期长势和生物量无显著影响，具有很好的应用前景。     

BR处理对小麦萌发生长及α—淀粉酶活性的影响

研究了不同小麦品种间萌发速率与α－淀粉酶活性的关系和同一品种用植物激素－油菜素内酯浸种后,小麦种子萌发和幼苗生长与α－淀粉酶活性的关系。结果表明,小麦不同品种间种子的发芽速率与α－淀粉酶活性呈正相关;用ＢＲ浸种处理后,小麦种子的发芽率有所提高,小麦种子的萌发速率和萌发期幼苗生长与α－淀粉酶活性呈正相关。     

FH-1和NJ-1混合菌发酵液缓解铅与莠去津复合胁迫下的大豆生长

为探究FH-1和NJ-1混合菌发酵液缓解铅(Pb²⁺)与莠去津复合胁迫对大豆种子及幼苗生长发育的影响。本研究采用液相色谱法测定了不同Pb²⁺浓度下FH-1和NJ-1 (3∶2)混合细菌对莠去津降解的影响。结果表明：添加0.02,0.04,0.06,0.08,0.1和0.2mol·L^-1 Pb²⁺后,第1天时低浓度0.02mol·L^-1 Pb²⁺对莠去津降解率有促进作用,随着Pb²⁺浓度的增加莠去津降解率均受到抑制作用;当培养第3天和第5天时,添加各浓度Pb²⁺后莠去津降解率均受到抑制作用。同时种子萌发试验和幼苗盆栽试验进一步表明,Pb²⁺与莠去津复合胁迫对大豆种子萌发、幼苗生长及根部发育均有显著抑制作用(P<0.05),且高于单一胁迫;而加入FH-1和NJ-1混合菌发酵液后,大豆种子发芽率和发芽长度分别提高了36.36%和46.76%。幼苗的相对茎叶干重和根长分别恢复38.60%和60...     

Simulation of soybean growth and yield in near-optimal growth conditions

SoySim is a new soybean (Glycine max, L. Merr) simulation model that combines existing approaches for the simulation of photosynthesis, biomass accumulation and partitioning with several new components: (i) flowering based on floral induction and post-induction processes, (ii) leaf area index based on logistic expansion and senescence functions, (iii) integration of canopy photosynthesis using a beta function, and (iv) yield simulation based on assimilate supply and seed number. Simulation of above ground dry matter (ADM) and seed yield by SoySim were validated against data from field studies at Lincoln (NE), Mead (NE), Whiting (IA), and West Lafayette (IN) that included 147 site-year-cultivar-planting date-plant-plant population combinations. In each of the four field studies, agronomic management other than planting date and plant population was optimized to achieve growth with minimal limitation from pests, nutrients, or other controllable factors. SoySim requires just two genotype-specific and two crop management-specific input parameters and yet provides reasonable accuracy in simulating growth and yield under optimum growth conditions across a wide range of sowing dates, plant population, and yield (2.5–6.4 Mg ha⁻¹) in the North-Central U.S. Corn Belt. Simulated seed yield had a RMSE of 0.46 Mg ha⁻¹. Few cultivar-specific parameter input requirements, lack of requirements for specification of key developmental stages, and mechanistic treatment of phenological development, canopy photosynthesis, and seed dry matter accumulation give several advantages to SoySim for use in research and for use as a decision-support tool to evaluate the impact of crop management options on yield potential in favorable environments.     

Lateral growth of a wheat dough disk under various growth conditions

Numerous studies have tried to understand and model bubble growth inside dough. Experimental studies are inconvenienced by the methods’ inability to capture the dynamic phenomena. In this paper, a versatile experimental method was developed to allow for macroscopic expansion of wheat dough. The study evaluates expansion of a dough disk under varying: moisture content (40, 41, 42, 43, and 44% wb), leavening acid concentration (30, 40, and 50% db), pressure schemas, pressurizing gas (compressed air and CO₂), and lubrication (Teflon^® film coating and Pam^® aerosol lubricant). Dough expansion increased 22.6% by increasing moisture content from 40 to 44%. Increased baking powder formulation (40% db) was used to enhance initial growth conditions and CO₂ production. ‘Pressure pulse’ and ‘pressure vacuum methods’ added pressurization alternatively with full vacuum. The former method included a rest period before vacuum application, and increased expansion by 10.8%. Teflon^® and Pam^® reduced friction between the dough and acrylic plate and increased the final expansion by 14.7% compared to no lubricant following the ‘standard pressurization method’. ‘Pressure pulse’ and ‘pressure vacuum’ experiments decreased expansion by 28.4 and 38.2%, respectively compared to ‘standard pressurization’ while using Teflon^® and Pam^®.     

Influence of the growth retardant B 995 on growth and yield of potatoes

Summary Stem elongation in a potato crop can be reduced by spraying the growth retardant B 995 on the foliage. This treatment generally did not change the total dry matter production. Only in the last period of growth did B 995-treated plots show a higher total dry weight than the untreated ones. This was caused by a slightly later senescence of the treated plots. The B 995 treatment caused a marked change in the dry matter distribution: stem weight was decreased and tuber weight increased, but leaf weight was generally not influenced. With plants showing considerable vegetative growth, these effects resulted in an increased tuber yield. High nitrogen plots treated with B 995 combined a long productive periode with a favourable dry matter distribution, producing a very high tuber yield at the end of the growing period.     

Retardation of shoot growth and promotion of tuber growth of potato plants by paclobutrazol

The relationship between shoot growth and tuber yield in potato plants (Solanum tuberosum L. cv. Russet Burbank) was studied under greenhouse conditions using paclobutrazol [(2R,3R + 2S,3S)-1-(4-chlorophenyl)-4,4-dimethyl-2-(l,2-4-triazol-l-yl)-pentan-3-ol), PP333], a growth retardant. Concurrent with reduction of stem elongation by the application of paclobutrazol to base of the main stem was a decrease in the dry weight of the shoot and an increase in the dry weight of the tuber. The inhibitory effect of paclobutrazol on stem elongation was reversed by gibberellic acid A₃ (GA₃). Leaf content of raffinose sugar and chlorophyll increased upon paclobutrazol treatment.     

The growth of individual tubers

Summary Single-stem plants cv.Maris Peer were grown in boxes with a tuber chamber attached so that the growth of individuol tubers could be followed. The length of the tuber-bearing stolons decreased the further they were formed from the base of the stem. Tubers formed on stolons arising from the basal nodes showed higher relative growth rates than those formed at nodes further from the base of the stem.     

Seedling growth of four grasses

Investigations were conducted into the seed reserves, shoot and seminal root growth of Lolium perenne, Festuca arundinacea, Holcus lanatus and Poa trivialis. Data are presented for the caryopsis, palea and lemma weights of these species. Shoot lengths of Lolium and Festuca were very similar but seminal root lengths of Lolium were longer and emerged earlier than those of Festuca. The caryopsis in Lolium lost weight much more rapidly in germination than Festuca. Seedlings of Lolium and Festuca showed similar increases in shoot length but Lolium had more rapid rates of seminal root growth and weight loss from the caryopsis. It is suggested that poor field establishment of Festuca may be due to poor mobilization of seed reserves and consequential poor seminal root growth. The possibility of selecting for good seminal root development in Festuca to improve establishment is suggested.     

营养元素与植物生长调节剂对油菜花粉萌发的影响

采用花粉离体培养技术研究营养元素与植物生长调节剂对油菜花粉萌发的影响。结果表明：在适宜的浓度范围内,硼、尿素、锌、钼、６－苄基腺嘌呤（ＢＡ）和萘乙酸（ＮＡＡ）对花粉萌发均有促进作用。０．０１％的硼砂和０．１％的尿素、０．１ｍｇ／Ｌ的硫酸锌、１０～４０ｍｇ／Ｌ的钼酸钠、１ｍｇ／Ｌ的ＢＡ和１０ｍｇ／Ｌ的ＮＡＡ促进花粉萌发及花粉管生长的作用最显著。     

花生不同密度群体施用植物生长调节剂对生长发育和氮素代谢的影响

花生不同密度群体喷施三十烷醇和Ｂ９，研究其对生长发育和氮素代谢的影响。三十烷醇对花生主茎生长和茎尖过氧化物酶活性无显著影响；Ｂ９则抑制了主茎生长，提高了主茎茎尖过氧化物酶活性。密度越大，Ｂ９的效果越明显。两种调节剂及密度对分枝及叶片出生速度无显著影响。三十烷醇增加了前期花而Ｂ９减少了后期花，密度的增大也减少前期花。三十烷醇和Ｂ９均提高了叶片硝酸还原酶活性（ＮＲ）和根瘤固氮活性，且两种调节剂具有累加效应，随着密度的增大，未喷Ｂ９的花生群体氮代谢受影响较大，喷Ｂ９的群体受影响较小。