壳聚糖对不同种源柠条种子发芽及其酶活性的影响

用不同浓度壳聚糖乙酸溶液分别对陕西省的吴起县和榆林市榆阳区两个产地的柠条种子浸种处理,以清水浸种处理为对照,调查种子发芽及幼苗生长特性,并测定了萌发过程中种子α-淀粉酶、脱氢酶、过氧化物酶、过氧化氢酶活性。结果表明,壳聚糖能促进柠条种子的萌发,缩短发芽时间;随着处理浓度的增大,各项发芽指标及各种酶活性先升高后降低,且不同种源柠条种子对壳聚糖浓度的反应不同。当壳聚糖浓度为0.5%时,榆阳柠条种子的发芽率是对照的1.2倍,平均发芽速率缩短0.9d,各种酶活性比对照显著提高,处理效果最佳。当壳聚糖浓度为1.0%时,吴起柠条种子发芽率比照提高13%,平均发芽速率缩短1.7d,各种酶活性比对照显著提高,处理效果最佳。当壳聚糖浓度达到1.5%时,对榆阳柠条种子的萌发有一定的抑制作用,而对吴起柠条种子萌发无抑制作用。壳聚糖对柠条幼苗的生长也有一定的影响,表现在幼苗的根长、苗高、干重、鲜重和叶绿素含量均显著高于对照,吴起柠条和榆阳柠条最佳的处理浓度分别为1.0%和0.5%。     

柠条种子采收与育苗技术

柠条根系发达,抗逆性强,适应性广,生态经济效益显著,是晋北、晋西北和吕梁山区立地条件极差造林地的首选优良树种.介绍了柠条的种子采收与育苗技术.     

镉对种子萌发的影响

采用室内培养研究了Ｃｄ对大麦、水稻种子萌发及根、芽生长的影响。结果表明,５ｍｇ／ＬＣｄ具有提高种子发芽率、发芽势、活力指数及促进芽生长的作用,高浓度的Ｃｄ则降低种子的发芽率和活力指数。Ｃｄ对根的抑制效应大于芽。水稻种子蓝发对Ｃｄ胁迫的抗性高于大麦。     

Cd胁迫对不同类型甜瓜种子萌发的影响

以薄皮、厚皮及野生3种类型甜瓜种子为试材,研究了在不同质量浓度Cd胁迫下甜瓜种子的萌发差异。结果表明,Cd质量浓度≤ 50 mg/L时,对甜瓜种子的发芽率没有明显影响;野生甜瓜种子对Cd胁迫最敏感,在200 mg/L的Cd胁迫下发芽率仅为6.7%;高质量浓度Cd胁迫下甜瓜种子胚根不能正常伸长,易产生无根苗。所有参试品种初生根长度均随Cd质量浓度增加而下降,而芽长均随Cd质量浓度增加先升后降,Cd质量浓度 ≥50 mg/L时,初生根长和芽长的降幅较大。各类甜瓜种子萌发的鲜重对Cd胁迫相对比较稳定。总体而言,Cd质量浓度越大,对甜瓜种子萌发的抑制作用越强。Cd对甜瓜种子萌发抑制作用因品种而异,所测各项指标均呈厚皮甜瓜耐受性最高,野生甜瓜最低,薄皮甜瓜居中的趋势。     

盐分胁迫对林木种子发芽率的影响研究

试验研究盐分胁迫对林木种子发芽率的影响结果表明 ,NaCl和NaCl KCl 2种盐分对林木种子发芽率和苗木生长均有一定抑制作用 ;随盐分浓度的提高而发芽率逐渐下降 ,幼苗生长呈相同趋势。与复合盐分相比 ,单一盐分对种子发芽和苗木生长抑制作用更强 ,表明K 可一定程度缓解Na 的危害 ,并提出耐盐指数概念     

NaCl胁迫对几种典型耐盐经济作物种子萌发的影响

研究黄秋葵、饭豆、海蓬子、碱蓬和三角叶滨藜 5种不同耐盐经济作物对 NaCl胁迫的响应,筛选耐盐能力强的品种,对改良盐碱地和提升土地利用率具有重要意义。用不同浓度 NaC1溶液进行胁迫处理,测量发芽率、发芽势、发芽指数。结果表明:NaCl胁迫下,不同耐盐经济作物种子发芽率、发芽势和发芽指数均随 NaCl浓度的升高而下降。NaCl浓度在 0～ 50 mmol/L时,黄秋葵发芽率最高;NaCl浓度在 50～ 250 mmol/L时,饭豆种子发芽率最高;不同耐盐作物耐盐程度大小依次为:饭豆 >黄秋葵 >海蓬子 >碱蓬 >三角叶滨藜。NaCl浓度在250～ 450 mmol/L时,仅有饭豆发芽率大于20%。当 NaCl浓度大于 500 mmol/L时,所有耐盐作物几乎都不发芽。综合分析表明,黄秋葵、饭豆均具有很强的抗盐性。黄秋葵在低盐环境下的耐盐性最好,饭豆在高盐环境下的耐     

温度对揉碎柠条可压缩性的影响

揉碎柠条的可压缩性对其压缩设备的设计和压缩生产工艺的选择有重要影响。该文通过对揉碎柠条在22～140℃范围内4个不同温度下的压缩试验,建立了柠条在压缩过程中压力与体积应变、压力与压缩密度以及体积模量与压缩密度的数学模型,获得了温度对揉碎柠条可压缩性的影响规律。研究结果表明：揉碎柠条在压缩过程中存在松散、过渡和压紧3个阶段,在松散阶段可压缩性较好,过渡阶段可压缩性逐渐降低,压紧阶段可压缩性迅速降低。同时,柠条的可压缩性与温度有关,在所选温度范围内,可压缩性随温度的升高而提高;且随压缩密度的增加,温度对其可压缩性的影响逐渐增强。研究结果为柠条压缩设备的设计及其加工工艺的合理选择提供了参考。     

顺流干燥种子发芽率的预测

构造并验证了种子发芽率一阶动力预测模型。预测了顺流干燥过程中种子发芽率,分析了干燥过程中谷物发芽率的变化规律,给出了保证种子发芽率损失在１０％以内的极限热风温度。     

不同种植密度人工柠条林对土壤水分的影响

通过对宁夏盐池干旱退化草场植被恢复与风蚀沙化防治技术示范区内不同种植密度的柠条林土壤水分进行了定位观测,从土壤水分日变化、季节性变化、水分垂直分布等方面进行了分析.结果表明土壤含水量主要受大气降雨及植物生长节律的影响,变化较大.0～100 cm土壤含水量的垂直分布规律为从表层到深层土壤含水量递增.林地土壤水分随着离柠条带距离的增加显著 (P<0.05)增加.种植密度不同土壤贮水量明显不同,密度分别为3 330丛/hm2(带间距4 m),土壤水分处于亏损状态,0～100 cm土壤贮水量极显著低于对照,柠条密度为2 490丛/hm2(柠条带间距7 m)和1 665丛/hm2(柠条带间距10 m)时,土壤含水量变化不大,但0～100 cm土壤贮水量极显著高于对照.针对盐池干旱风沙区,柠条林种植适宜密度为7 m或大于7 m为宜.退化草场种植密度土壤水分干旱风沙区.     

柠条堆肥结合翻耕对设施黄瓜产量和土壤质量的协同影响

研究柠条堆肥结合不同翻耕深度对土壤质量和产量的影响,为西北地区农业废弃资源利用及设施农田稳定健康发展提供理论依据。本研究以设施主栽黄瓜为研究对象,利用连续3茬的田间定位试验,设计传统鸡粪和柠条堆肥两个底肥处理,在此基础上进行不同耕作处理,分别为免耕、翻耕15 cm、翻耕35 cm、翻耕45 cm,共8个处理。分析底肥和翻耕对黄瓜连作土壤养分、酶活性、黄瓜生物量和产量的协同影响作用。结果表明:(1)与传统鸡粪相比,柠条堆肥施用下pH和土壤肥力指数分别显著提升了1.42%和1.84%,土壤EC值、有机质含量、有效磷含量、脲酶活性和磷酸酶活性分别降低了2.61%、5.36%、27.84%、3.51%和3.44%,连续种植后这种差异逐渐减弱,两种肥料处理对黄瓜产量无显著影响。(2)土壤EC值、全氮含量、全磷含量、有效磷含量、脲酶活性均随翻耕深度增加而降低,且免耕和翻耕15 cm处理间的氮素和磷素含量无显著差异,并显著高于其他翻耕处理,而不同耕作处理间黄瓜产量无显著差异。土壤肥力指数随翻耕深度的增加呈先增加后降低的趋势,翻耕15 cm处理土壤肥力指数最高,较其他处理分别显著提高1.20%、5.35%和9.92%。(3)连续种植后土壤有机质和磷素得到累积,且黄瓜产量受栽培季节的影响,秋冬茬黄瓜产量低于早春茬,但土壤肥力变化趋势与之相反。因此,柠条堆肥的连续施用促进了设施黄瓜的增产和土壤肥力的提升,同时结合深翻改善了土壤养分的表层累积,有效缓解了土壤酸化和盐渍化,栽培季节显著影响土壤肥力和黄瓜产量。     

Seed Mass,Shape and Dormancy in Arid Temperate Degraded Grassland in Northeastern Inner Mongolia,China

Extensive studies have been conducted on the relationship between seed mass, shape and persistence in soil. However, the relationship between seed mass, shape and dormancy remains unclear. Therefore, in the present study, we investigated the possible relationship of seed mass and shape with dormancy in 124 plant species from different families, differing in their growth forms, in an arid temperate degraded grassland in northeastern Inner Mongolia, China. One‐tailed t‐test was applied to assess the differences in seed mass and shape between dormant and non‐dormant species. Phylogenetically independent contrasts were used to determine whether divergence within individual clades between dormant and non‐dormant seeds was associated with seed mass or seed shape. Our results indicate that the dormant seeds were heavier than 1 mg. Species with dormant seeds had significantly larger seed mass than those with non‐dormant seeds (one‐tailed t‐test = −3·56, p = 0·0005), but there was no significant difference in seed shape between them (one‐tailed t‐test = 0·86, p = 0·195). Furthermore, the relationship between seed mass, shape and dormancy was observed to be linked to phylogeny. Copyright © 2016 John Wiley & Sons, Ltd.     

内蒙古自治区鄂尔多斯高原茭蒿种子萌发特性研究

通过对内蒙古自治区鄂尔多斯高原的茭蒿与其他2种蒿属植物种子萌发特性的对比研究。结果表明,茭蒿种子质量很小,千粒重仅为(0.090 1±0.005 1)g,这种特性有利于其种子的传播;茭蒿种子质量虽然很小,但在相同条件下,与其他植物种子发芽率并没有表现出显著差异,即种子质量的大小没有对茭蒿种子的萌发造成影响。茭蒿在拥有小种子的同时又具有高的种子萌发率,是其对黄土丘陵沟谷的有效适应途径。     

苜蓿不同器官水浸提液对中间锦鸡儿种子萌发的影响

为了探讨苜蓿不同器官水浸提液对中间锦鸡儿种子萌发的化感影响,采用生物测定法,研究了苜蓿根、茎叶不同浓度水浸提液（0.5,1.0,5.0,10.0,25.0 mg/ml）对中间锦鸡儿种子萌发及幼苗生长的化感作用。结果表明,苜蓿不同器官水浸提液对中间锦鸡儿种子萌发有明显的抑制作用,随着苜蓿各器官水浸提液浓度的增加,抑制作用增强。相同浓度下根水浸提液对中间锦鸡儿种子萌发的抑制作用大于茎叶水浸提液。当苜蓿各器官水浸提液为1.0 mg/ml浓度时,中间锦鸡儿幼苗的胚根长、胚轴长、苗高均高于对照;而在25.0 mg/ml浓度时,各器官水浸提液对幼苗则表现出显著的抑制作用（P < 0.05）。本文通过研究苜蓿和中间锦鸡儿的化感作用,以期为人工建置灌草间作提供理论基础。     

紫茎泽兰凋落物提取液对自身种子萌发和幼苗生长的影响

采用恒温培养法研究了不同浓度紫茎泽兰凋落物提取液对其种子萌发和幼苗生长的影响。结果表明:紫茎泽兰凋落物提取液对自身种子萌发与幼苗生长起到一定程度的抑制作用,并且浓度越高抑制作用越强;当提取液浓度低于0.05g/ml时,种子萌发和幼苗生长过程中各指标与对照均无显著差异(p0.05);提取液浓度高于0.05g/ml时,种子发芽率、发芽势、发芽指数、胚根长、幼苗鲜重和干重随提取液浓度的增加急剧降低(p0.05),并且紫茎泽兰凋落物提取液延长了种子发芽时间,而对幼苗鲜重和干重影响不显著(p0.05);高浓度(0.30g/ml)紫茎泽兰凋落物提取液致使种子失活。统计相关检验表明,紫茎泽兰叶片丙二醛(MDA)含量、细胞膜透性均与提取液浓度呈显著的线性正相关(p0.001),叶绿素含量、根系活力(TTC)、保护性酶(POD,SOD,CAT)和非保护性酶(PPO,PAL)活性均与提取液浓度呈显著的线性负相关(p0.001)。综合以上结果表明紫茎泽兰凋落物提取液对其种子萌发和幼苗生长存在一定程度的自毒作用。     

Effect of Boron on Dynamic Change of Seed Yield and Quality Formation in Developing Seed of Brassica napus

Rapeseed (Brassica napus) is one of main oil crops in the world and also a potential bioenergy crop. Because of the sensitivity of Brassica napus to boron (B) deficiency and the wide distribution of low available-B soils in main areas of rapeseed production, more and more attention is being paid to the effect of B nutrition on yield and quality of rapeseed and its regulation mechanism. In this study, a field plot trial was conducted to examine the effects of B on dynamic changes of seed yield and quality formation in developing rapeseed. The results showed that B significantly increased seed yield compared with the low B control, which was attributed to an increase in the number of seeds per pod and pods per plant. During the seed development period, dry matter accumulation of seed followed a typical S-shaped curve at the two B treatments, but seed weight accumulated faster in plants supplied with sufficient B than those with low B. The dry weight of the podwall in high B treatment showed rapid increase at the early stage of seed development and decreased rapidly in later periods compared with low B. This suggested that applying B improved the accumulation of seed dry matter in early stages of seed development and substance transport from podwall to seed in later stages, which resulted in high seed yield. No significant effect of B on oil content, erucic acid and glucosinolate contents was found. However, B maintained a lower level of erucic acid and glucosinolate contents at whole seed development process and resulted in a lower ratio of erucic acid (22:1)/oleic acid (18:1) compared with that of low B treatment. These results suggested that application of B could heighten seed yield and improve oil quality for rapeseed in soils with low available B.     

美国城镇有害生物综合治理策略及其借鉴

对美国城镇有害生物综合治理的概念、组成、目标、主要内容及技术应用体系进行概括和阐述,以对我国城镇有害生物综合治理事业的发展提供借鉴。     

苦豆子和披针叶黄华种子特性及硬实破除研究

苦豆子和披针叶黄华种子形状、颜色、表面状态差异显著,种子健壮度和硬实率很高,含水量都很低且差异不显著;苦豆子种子长度显著大于披针叶黄华,披针叶黄华种子体积质量和千粒质量显著大于苦豆子,两种豆类宽度、厚度和相对密度之间无显著差异;在新鲜干净的两个豆类种子中,硬实种子和非硬实种子同时存在,破除苦豆子和披针叶黄华种子硬实的最佳措施是：90%的H2SO4处理70 min和120 min;破除硬实的两种豆类种子萌发的物质转化效率达到了77.94%和77.28%,苦豆子和披针叶黄华种子开始萌发时间均为21 h,最低萌发需水率分别为151.05%和151.71%,两种种子萌发相对需水较多,苦豆子种子萌发40 h达最大发芽值,披针叶黄华种子56 h达最大发芽值。     

机器视觉技术在农作物种子质量检验中的应用研究进展

我国农作物种子资源丰富，随着图像处理技术的专业化与计算机硬件成本的下降和速度的提高，利用机器视觉技术进行种子质量检验评价成为可能。该文概述了农作物种子的特性及其对质量检验技术的要求，介绍了机器视觉技术的基本理论和发展现状，从算法、硬件、研究进展几个方面综述了机器视觉技术在农作物种子质量检验中的应用，认为用机器视觉代替人的视觉进行农作物种子质量检验前景广阔。     

矿物类风沙土改良剂对小叶锦鸡儿生理特性和生长状况的影响

通过盆栽试验,并运用多元统计的方法分析矿物类改良剂Arkadolith对风沙土的改良效果以及对小叶锦鸡儿生理特性和生长状况的影响,结果表明:Arkadolith改良剂对风沙土理化性质的改良作用明显,表现为土壤容重、总孔隙度、pH值、EC值、>0.25 mm水稳性团聚体、全氮、有效磷、速效钾、有机质明显改善;促进了小叶锦鸡儿的生长,表现为小叶锦鸡儿的蒸腾速率、高生长和生物量明显优于对照,同时当风沙土中施入10%的Arkadolith改良剂时最有利于小叶锦鸡儿的生长。Arkadolith土壤改良剂作为一种新型矿物改良剂,改良土壤的作用更加长久、高效,并且更加安全、环保,同时更有利于植物生长。     

Autotoxicity of Phthalate Esters in Tobacco Root Exudates:Effects on Seed Germination and Seedling Growth

Autotoxicity is one of the major factors that impede continuous cropping. It is defined as the toxic influence of chemicals released from one plant species on the germination and growth of individuals of the same species. Here, in order to exam the autotoxicity of tobacco root exudates, root exudates were collected from tobacco plants grown both in cultural solution and on natural soil. Using ultraperformance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry, main autotoxic chemical substances in the root exudates were identified. The autotoxic effects of suspected autotoxins on seed germination (including germination rate, germination potential, germination index, and vigor index) and seedling growth were analyzed. Dibutyl phthalate (or diisobutyl phthalate), dioctyl phthalate, and diisooctyl phthalate were identified in tobacco root exudates. It was observed that high concentrations (greater than 0.5 mmol L^-1) of each identified phthalate ester caused significant (P < 0.05) inhibition of tobacco seed germination and seedling growth. It can be concluded that phthalate esters such as dibutyl phthalate, diisobutyl phthalate, and diisooctyl phthalate in tobacco root exudates may play an important role in tobacco autotoxicity.