东北春玉米不同发育期干旱胁迫对根系生长的影响

分别在玉米拔节期(BJ)和抽雄期(CX)进行水分胁迫试验,利用微根管技术观测不同发育期干旱过程中根分布动态,并利用根分布模型模拟相关参数(d_(50)和d_(95):累积根比例分别为50%和95%的土层深度),对不同干旱胁迫处理的土壤湿度、根系分布及相关参数时空动态特征进行分析。结果表明:水分控制后的土壤湿度在130cm以上基本达到预期干旱效果,即BJ和CX处理在控水时段0~100 cm土层土壤相对湿度都降至40%以下,但深层土壤湿度并未受到水分控制影响;拔节和抽雄期干旱胁迫条件下,根长密度(RLD)最大值分别为2.18±0.89cm·cm~(-3)和2.10±0.47 cm·cm~(-3),所在土壤深度为60 cm,对照(CK)RLD最大值为1.24±0.77 cm·cm~(-3),所在深度为40 cm,CK和BJ处理的RLD在最大值深度以下随土层深度增加而减小,CX处理的RLD在80 cm以下仍保持较大值;BJ和CX比CK的d50分别增大45%和59%,d95分别增大8%和41%,证明玉米根系因干旱胁迫而向深层土壤生长。     

不同土层深度苜蓿断根后对其株高生长的影响

对苜蓿进行不同土层深度断根处理,以阻断其不同深层根系对土壤水分的吸收,研究苜蓿地上部分株高生长的反馈特征。结果表明:苜蓿在不同土层断根当年,各深度的断根处理均使苜蓿株高生长受到一定抑制,与对照相比有所降低。不同层次断根的苜蓿在断根当年浅层次断根(20、406、0 cm)受到的水分胁迫较其它处理严重。在断根初期(半个月)与对照呈极显著差异;在收获期株高与对照(26.70 cm)相比,株高分别降低了13.10、12.851、1.30 cm,表现为断根越浅,影响越大。各处理在断根的次年,苜蓿返青期的株高变化曲线十分平缓。收获期断根处理20、402、30 cm的苜蓿株高比对照(37.96 cm)分别降低了5.08、5.34、5.30 cm,较对照差异性极显著(P0.01),各断根处理较断根当年株高的生长量均有显著提高。两年的数据表明浅层次断根处理的株高生长受到水分胁迫较深层断根处理严重。不同土层断根处理的株高生长受抑制程度为:浅层次处理中层次处理深层次处理。     

滴灌次数对冬小麦根系生长及时空分布的影响

以新冬18号为材料,利用双管分根管栽法,模拟田间试验研究了拔节期后不同滴灌次数W1（6次）、W2（7次）、W3（9次）、W4（11次）（每次内、外管分别滴30 mm ）对0～100 cm土层含水量,0～100 cm土层初、次生根干重和长度、根系活性分布及产量的影响。结果表明,随滴灌次数及总滴灌量的增加,0～40 cm土层的含水量增加,并延缓该土层的初生根干重和根长的衰减、促进次生根干重和根长增长,增加孕穗期至花后20 d初、次生根干重密度、根长密度及根系活性,而对40～100 cm土层根系的生长影响较小。小麦产量和水分利用效率均以W4最高,分别为25．5 g·管－1和1．36 kg·m－3。当滴灌量少、湿润土层浅时,小麦深层初、次生根生长易受严重抑制,且根系分布浅,初生根提前衰老,导致千粒重降低而减产。     

利用HYDRUS-2D模拟膜下滴灌玉米农田深层土壤水分动态与根系吸水

河套灌区农田地下水埋深普遍较浅且年内波动较大,明确不同膜下滴灌条件下深层土壤水分对根区的补给作用及作物根系吸水的响应差异有利于膜下滴灌技术的完善和推广。本研究开展了连续2 a(2017—2018年)的春玉米田间试验,设置3个膜下滴灌灌溉水平,分别控制土壤基质势下限为-10 kPa(S1)、-30 kPa(S3)和-50 kPa(S5)。利用HYDRUS-2D模型模拟0～120 cm深度土壤含水量、根层下边界(100 cm深度处)水分通量和作物根系吸水速率。结果表明,经过率定后的HYDRUS-2D模型对0～120 cm深度土壤含水量模拟结果的根均方差(RMSE)和决定系数(R~2)分别为0.039～0.042 cm~3·cm~(-3)和0.78～0.73,模拟结果可靠。膜下滴灌农田100 cm和120 cm深度处土壤含水量较高且处理间差异不大,说明不同滴灌条件对于100 cm以下深层土壤含水量影响较小;但不同处理显著影响根区下边界的水分通量和根系吸水速率。基质势下限控制水平越低,深层土壤水分对于根区的补给量(毛管上升)越大,S1、S3、S5生育期内累积补给量在31.9～49.6 mm之间。S5处理根系吸水速率较低,根系吸水受到显著抑制,从而造成作物生长指标和产量显著低于S1和S3处理(P0.05);而S1和S3之间籽粒产量差异不显著。综上,在本研究所设置的3个滴灌处理中,S3生育期内灌溉定额为240～300 mm,既较S1显著减少灌水量、提高水分利用效率,又具有较好的根系活力,有效利用深层土壤水分,因此建议该地区春玉米膜下滴灌的灌水下限为-30 kPa。     

基于水分变化的沙地樟子松人工林土壤分层特征

研究了章古台地区沙地樟子松人工林不同林龄(10a,20a,35a,50a,60a)不同深度(20cm,40cm,60cm,80cm,100cm,120cm,140cm,160cm,180cm)的土壤含水量变化的分层特征。结果表明:沙地樟子松人工林地各土壤层次水分含量随林龄的不同表现各异。依据土壤含水量的不同将沙地樟子松人工林地土壤层次分为3层,即表层、根系层和稳定层,各林龄的层次分别为:10a林龄林地无明显表层,100cm土层以上为根系层,120cm土层以下为稳定层;20a林龄林地40cm以上为表层,60-140cm为根系层,160cm以下为稳定层;35a林龄林地40cm土层以上为表层,60-100cm为根系层,120cm以下为稳定层;50a林龄林地40cm以上为表层,60-120cm为根系层,140cm以下为稳定层;60a林龄林地40cm以上为表层,60-100cm为根系层,120cm以下为稳定层。     

不同覆盖方式对烟苗根系生长及耕层生态环境的影响

研究了塑料地膜覆盖(DM)、液体地膜覆盖(YM)和露地栽培(CK)3种栽培方式对烟苗根系生长及耕层生态环境的影响,结果表明:移栽后5~45 d,5~20 cm不同耕层,3种方式对地温的影响均表现为DM>YM>CK;DM的保水效应在0~10 cm表耕层较为突出,10~20 cm耕层及20~30 cm耕层DM和YM差异不大,而深层土壤(30~40 cm)则YM高于DM和CK;移栽后30 d4、5 d,烟株地上部总干重、根总干重、根冠比、一级侧根数量、二级侧根数量、一级侧根粗和茎基部伤流强度均表现为DM>YM>CK,3种栽培方式间差异均达极显著水平;液体地膜覆盖烟株根系最长,极显著高于DM和CK。     

植物生长调节剂Z-S对高产旱稻花后衰老的影响

利用植物生长调节剂Z-S对高产旱稻北农大65在三叶一心、拔节期和孕穗期进行叶面喷施,研究其对高产旱稻花后衰老的影响.结果表明:浓度为100 mg/kg Z-S叶面喷施后根系活力、根系SOD、CAT活性及可溶性蛋白质含量均明显高于其它处理;100 mg/kg Z-S喷施后旗叶可溶性蛋白质含量明显增加,而旗叶SOD、CAT活性较其它处理没有明显上升,高浓度处理(≥300 mg/kg)促进植株体内MDA累积,造成早衰.从产量方面看,100 mg/kg的Z-S喷施能有效提高旱稻的产量和经济系数.     

尖叶胡枝子地下生物量累积变化

通过对栽培条件下尖叶胡枝子地下不同直径根系组分和生物量的测定及模拟分析,结果表明:尖叶胡枝子的根系垂直空间分布为典型的表层聚积型,根系主要集中在0～20 cm,根系垂直分布特征参数β的值较小;生长1 080 d(生长3年)的尖叶胡枝子根系入土深度可达100 cm,其中在0～40 cm的土层中,以粗根为主,占总根量的81.54%,40 cm之下以细根为主;根系密度随着尖叶胡枝子生长期的延长呈明显增大的趋势.     

水分调控对小麦旗叶叶绿素荧光动力学参数及其产量的影响

在小麦全生育期遮雨条件下,利用植物效能分析仪研究了不同灌水对小麦旗叶叶绿素荧光动力学参数日变化的影响。结果表明,Fo,Fm,Fv,Fv/Fm及Fv/Fo日变化均呈"V"字型,其中Fo以9∶00～11∶00最低;Fm,Fv,Fv/Fm及Fv/Fo以15∶00最低。不同灌水处理间,Fo以拔节期 抽穗期灌2水处理为最大;而Fm,Fv,Fv/Fm及Fv/Fo以拔节期 抽穗期 花后10d灌3水处理的为最大。表明小麦生育期间增加灌水可以改善旗叶叶绿素荧光动力学参数,提高籽粒产量。但随着灌水次数的增加,田间耗水量增加,水分利用效率明显下降。     

不同生育阶段灌水处理对谷子生长发育的调控效应

在敦煌年降雨量39 mm条件下,研究了拔节期、抽穗期、灌浆期不同生育阶段灌水处理对谷子农艺性状及产量的影响。试验结果表明:不同生育阶段灌水对谷子主要农艺性状及产量都有较大影响,与全生育期不灌水相比,拔节期、抽穗期、灌浆期各灌1次水处理谷子生育期缩短5.4 d,株高增高51.1 cm,穗长增长1.2 cm,株穗重、株粒重和株草重分别增重14.2、12.3 g和3.1 g,产量增加225.85 kg·666.7m-2;全生育期不灌水处理谷子产量最低,仅105.78 kg·666.7m-2,抽穗期和灌浆期共灌2次水,拔节期、抽穗期、灌浆期共灌3次水和抽穗期仅灌1次水各处理,产量分别达339.91、331.64 kg·666.7m-2和288.31 kg·666.7m-2,灌2次水产量最高。表明抽穗期灌水对谷子产量形成影响最为显著。灰色关联度分析表明,单株粒重、单株穗重和主穗长与产量相关性最为密切。     

糜子对铁矿复垦生土施肥的生物学响应

以襄汾溃坝区复垦生土为栽培基质，采用盆栽试验的方法，研究了施肥对糜子生长及生理生态效应的影响。结果表明：在施钾的基础上施用N、P、NP及有机肥均有利于糜子的生长，表现为株高分别增加了6.1%、42.0%、52.7%、45.1%,叶面积分别增加了197.6%、207.7%、261.6%、232.5%,地上部干重分别增加了46.3%、159.1%、186.6%、148.2%,根重分别增加了13.8%、65.9%、75.7%、67.1%,总根长分别增加了5.0%、68.4%、99.8%、91.6%,根系总吸收面积分别增加了24.9%、50.8%、68.3%、62.2%,活性吸收面积分别增加了46.9%、57.7%、96.9%、58.9%。糜子的旗叶净光合速率、叶绿素含量、可溶性糖含量、根系超氧化物岐化酶（SOD）活性、过氧化物酶（POD）活性、丙二醛（MDA）含量等各项生理指标与糜子的生长状况表现出高度的一致性。并最终表现为施用各种肥料均有利于糜子产量的提高，施用N、P、NP及有机肥分别比对照增产80.6%、200.1%、266.8%、230.6%。比较不同处理的增产效果可以发现，在本试验条件下，施磷的效果好于氮，磷是所用生土肥力形成的首要因素，也是糜子产量形成的限制因子。磷、氮、钾三要素之间表现出明显的正交互效应。单施有机肥，在糜子生长前期（拔节期），对糜子的生长有明显的促进作用，但在后期（抽穗期）因缺氮而表现出效果不及其他处理。糜子根际土壤磷酸酶以及脲酶的活性与根系的生长状况表现为显著的正相关关系，表明发达的根系可以促使根际微生物群落的迅速生长和繁殖，并进而提高了根际土壤酶的活性，使得根际原来的生土不断向着熟化的方向发展。在施用一定肥料的前提条件下，矿区复垦生土地上种植糜子，当年便可获得较为正常的产量，并获得较好的经济效益，是当地可选的先锋杂粮作物之一。     

Growth and regenerative capacity of plants of Cirsium arvense

The undisturbed growth and regenerative capacity of the root system of Cirsium arvense (L.) Scop, were studied in one glasshouse and one field experiment. In the glasshouse experiment, two lengths of root fragment from the same clone, previously grown at two nitrogen levels, were planted in boxes. Plants that developed from these fragments were inspected on eight occasions to assess their undisturbed development and growth, above and below ground, and their regenerative capacity after disturbance by burial at different points of development. The initial nitrogen content of the roots had no effect on growth measurements, but longer root fragments produced greater masses of primary shoots, new roots and shoots from the new roots than did shorter ones. After disturbance at early stages (4-7 leaves with a minimum length of 5 cm), plants originating from shorter root fragments did not regrow at all. Plants originating from longer root fragments exhibited a minimum regenerative capacity when disturbed at the eight-leaf stage. In the field experiment, root fragments of length 12 cm. from the same clone, were planted in October 1991 at 5 cm or 20 cm depth. Plants that developed from these fragments were studied on 12 occasions, from April to July 1992. Plants emerging from a depth of 20 cm reached a point of positive net assimilation 28 days (380 day degrees) later than those developing from a depth of 5 em. The plants exhibited a minimum regenerative capacity when their primary shoots had. on average. 10 (plants from 5-cm root fragments) or seven (plants from 20-cm root fragments) expanded leaves.     

Comparative metabolism of atrazine and EPTC in proso millet (Panicum miliaceum L.) and corn

The purpose of this study was to examine the differential activities of proso millet (Panicum miliaceum L.) and corn (Zea mays L.) with respect to atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-S-triazine] and EPTC (S-ethyldipropyl thiocarbamate) metabolism. GSH-S-transferase was isolated from proso millet shoots and roots. When assayed spectrophotometrically using CDNB (1-chloro 2,4-dinitrobenzene) as a substrate, the shoot enzyme had only 10% of the activity of corn shoot enzyme while the root enzyme had 33% the activity of corn root enzyme. However, when proso millet shoot GSH-S-transferase was assayed in vitro using ¹⁴C-ring-labeled atrazine, it degraded the atrazine to water-soluble products at the same rate as the corn shoot enzyme. Incubation of excised proso millet and corn roots with [¹⁴C]EPTC indicated that uptake of EPTC was similar in both plants. However, proso millet metabolized the EPTC to water-soluble products at only half the rate of corn. Glutathione levels of proso millet roots were 35.9 μg GSH/g fresh wt, compared with 65.4 μg GSH/g fresh wt for corn. However, a 2.5-day pretreatment with R-25788 (N,N-diallyl-2-2-dichloroacetamide) elevated proso millet GSH levels to 62.7 μg GSH/g fresh wt. R-25788 did not elevate the activity of proso millet GSH-S-transferase, in contrast to its effects on corn. We conclude that differences in response to atrazine and EPTC in proso millet and corn are a result of their differential metabolism.     

除草剂与安全剂混用对杂草防效及糜子安全性的影响

为探讨除草剂与安全剂混用对杂草的防治效果及对糜子安全性的影响,以'榆糜2号'为试验材料,在糜子三叶期选取两种茎叶型除草剂——阔世玛(3.6％ 二磺 ? 甲碘隆水分散粒剂)和锐超麦(20％ 双氟 ? 氟氯酯可湿性粉剂)与两种安全剂——芸苔素内酯(brassinolide,BR)和赤霉素(gibbrellic acid,G...     

旱地小麦产量及其构成因素灌溉效应的模拟分析

为揭示灌水时期与灌水量对黄土丘陵区小麦产量及其构成因素的影响规律，依据黄土丘陵典型区域定西1971-2016年气象数据及定西市安定区凤翔镇安家沟村2016年大田试验数据，利用APSIM（Agricultural Production Systems Simulator）平台，动态模拟各灌溉处理下的小麦生长发育过程，并对各灌溉响应进行模拟分析。结果表明：小麦全生育期需水量为315.25 mm，各生育阶段需水量为播种~出苗21.13 mm、出苗~分蘖26.60 mm、分蘖~拔节33.27 mm、拔节~孕穗77.17 mm、孕穗~开花69.31 mm、开花~灌浆36.19 mm、灌浆~成熟51.58 mm。为提高产量，最佳灌水时期应在播种至拔节，灌水量不宜超过60 mm；开花前各生育阶段灌溉处理都明显提高了单位面积籽粒数量，其中以分蘖~拔节阶段（TS）最明显，拔节~孕穗阶段（JS）灌水量不宜超过80 mm、孕穗~开花阶段（BS）灌水量不宜超过20 mm。开花~灌浆阶段（FS）灌水量40 mm对粒重增加的促进作用最明显。     

覆膜方式对旱地糜子光合特性及产量的影响

以晋黍7号为材料,研究了旱地不同覆膜方式对糜子各生育期植株绿叶面积、叶绿素相对含量（SPAD ）、光合特性及产量的影响。试验结果表明,与平膜穴播和露地条播相比,分蘖期至成熟期,膜侧穴播处理的糜子平均旗叶SPAD分别提高3．8％、10．2％;单株绿叶面积分别提高17．9％、59．1％;拔节期至成熟期,膜侧穴播处理的糜子平均旗叶净光合速率较平膜穴播和露地条播分别增加3．8％、28．7％,旗叶蒸腾速率分别增加7．5％、23．4％,叶片瞬时水分利用效率（LWUE ）下降幅度较平膜穴播和露地条播分别低16％、25％。在不同的覆膜方式中,膜侧穴播处理的糜子产量最高,较平膜穴播和露地条播分别增加7．6％、51．2％。因此,膜侧穴播有利于糜子光合和产量的提高。     

不同氮水平下化学调控对旱地冬小麦生长及产量的影响

通过田间试验研究了不同氮水平下分阶段采用多效唑及其与6-BA配合对小偃6号和小偃22两小麦品种生长及产量的影响.结果表明,多效唑浸种显著增加了小麦的单株分蘖,拔节初期喷施多效唑明显降低了两品种的株高.不同生长阶段使用生长调节物质均增加了两品种的叶面积和叶片叶绿素SPAD值,尤其以灌浆初期喷施6-BA后对成熟期叶片SPAD值的增加幅度最为突出,表明其具有延缓叶片衰老,延长叶片功能期的效果.采用多效唑及其与6-BA配合进行分阶段化学调控具有明显增产作用,其中多效唑与6-BA相结合处理较清水处理小麦产量提高了601.2 kg/hm2,增产幅度达显著水平;小麦穗粒数和千粒重的增加是其籽粒增产的主要原因.由此可见,在小麦生长的不同阶段采取不同的化控措施,可以有效地调节小麦生长发育,达到提高作物产量的目的.     

不同灌溉模式对西辽河平原玉米根系形态特征和生理生化特性的影响

研究了西辽河平原灌区3种主要灌溉方式(浅埋滴灌、膜下滴灌和传统畦灌)对玉米根系形态特征和生理生化特性的影响.采用大田对比试验,以农华101为供试品种,大小垄种植(小垄行距40 cm,大垄行距80 cm),种植密度7.5万株·hm-2,在设定的灌溉定额下(膜下滴灌和浅埋滴灌为3150 m3·hm-2、传统畦灌为4500 ...     

Response of root traits of Reaumuria soongorica and Salsola passerina to facilitation

C3 plant Reaumuria soongorica and C4 plant Salsola passerina are super xerophytes and coexist in a mixed community in either isolated or associated growth, and interspecific facilitation occurs in associated growth. In the present study, the root traits including root distribution, root length(RL), root surface area(RSA), root weight(RW) and specific root length(SRL) of both species in two growth forms were investigated to clarify their response to facilitation in associated growth. Six isolated plants of each species, as well as six associated plants similar in size and development were selected during the plant growing season, and their roots were excavated at 0–10, 10–20, 20–30, 30–40 and 40–50 cm soil depths at the end of the growing season. All the roots of each plant were separated into the two categories of fine roots(2 mm diameter) and coarse roots(≥2 mm diameter). Root traits such as RL and RSA in the fine and coarse roots were obtained by the root analyzing system WinRHIZO. Most of the coarse roots in R. soongorica and S. passerina were distributed in the top 10 cm of the soil in both growth forms, whereas the fine roots of the two plant species were found mainly in the 10–20 and 20–30 cm soil depths in isolated growth, respectively. However, the fine roots of both species were mostly overlapped in 10–20 cm soil depth in associated growth. The root/canopy ratios of both species reduced, whereas the ratios of their fine roots to coarse roots in RL increased, and both species had an increased SRL in the fine roots in associated growth. In addition, there was the increase in RL of fine roots and content of root N for S. passerina in associated growth. Taken together, the root growth of S. passerina was facilitated for water and nutrient exploration under the interaction of the overlapped roots in both species in associated growth, and higher SRL allowed both species to more effectively adapt to the infertile soil in the desert ecosystem.