水分胁迫条件下几种化学材料对玉米幼苗抗旱性的影响

通过玉米盆栽试验,研究了在水分胁迫条件下,泥炭、沸石、稀土、保水剂等不同特性化学材料对玉米幼苗生长及生理的影响。结果表明,这些化学材料能够部分补偿水分胁迫给玉米带来的伤害,提高玉米幼苗的抗旱性能,并且各类化学材料的作用效果是不同的。     

保水剂施用方式对马铃薯产量和水分利用效率的影响

采用盆栽试验,比较深施、浅施、侧施、全施和不施(对照)等保水剂应用方法在充分供水和水分亏缺两种供水条件下,马铃薯(Solanum tuberosum L)生长、产量和水分利用效率(WUE)效应.结果表明,除浅施处理外其它方式施用保水剂处理都能促进马铃薯株高,水分胁迫下能促进马铃薯根系发育.在充分供水和水分胁迫下,深施保水剂使马铃薯产量较对照提高9.4%和16.6%,WUE提高12.82%和54.73%,侧施保水剂使马铃薯产量较对照提高39.4%和21.5%,WUE提高58.79%和59.46%;在水分胁迫下,全施保水剂使马铃薯产量和WUE较对照分别提高15.4%,56.76%.     

花期前后不同干旱过程对玉米抗旱生理反应的影响

本试验对盆栽玉米分别进行了正常供水；花前水分胁迫、花后正常供水；花前正常供水、花后水分胁迫共3种水分处理，在玉米生长的拔节期、喇叭口期、花期及成熟期进行了生理特性测定，研究了花前花后水分胁迫对根系伤流量、生长参数、活力及叶片生理特性的影响。结果表明，花期是玉米开始衰老的关键时期。正常供水条件下，玉米的根系伤流液量、根系活力、CAT活性、POD活性及膜透性呈现上升趋势，在开花期达到高峰后开始下降。花前水分胁迫条件下，根系活力减弱，保护酶活性较低，MDA含量显著增加。花后水分胁迫条件下，玉米保护酶活性有大幅的减弱，花前水分胁迫对玉米生长的影响是花后补充供水难以恢复的。     

接种丛枝菌根对玉米生长与抗旱性的影响

采用盆栽试验,研究了水分胁迫下接种丛枝菌根真菌对玉米生长及其抗旱性的影响。结果表明:玉米与丛枝菌根可形成良好的共生关系,接种丛枝菌根显著提高了玉米生物量、株高、地径。与未接菌相比,接菌提高了植株水分利用效率,水分胁迫和正常供水条件下,较对照分别提高117%和24.6%。接菌后玉米叶片SPAD值和可溶性蛋白含量增加,叶片过氧化氢酶活性增强。同时,接种菌根显著降低了植株叶片脯氨酸、丙二醛含量,干旱胁迫和正常供水条件下,较未接菌处理分别降低了14.1%、18.9%和59%、69%。由此可见,接种丛枝菌根真菌能够促进玉米的生长,缓解干旱胁迫对玉米生长造成的不利影响,提高了玉米的抗旱性。     

水分胁迫下不同化学物质浸种对玉米发芽及幼苗生长的影响

通过室内培养试验研究了不同水分胁迫条件下不同化学物质浸种对玉米种子发芽和幼苗生长的影响。结果表明：水分胁迫下使用化学物质浸种对玉米种子的发芽率和发芽势无显著影响,但却不同程度提高了玉米幼苗的株高和壮苗系数;使用化学物质浸种增加了玉米幼苗的生物量,且水分胁迫下幼苗干重增加幅度明显高于正常水分处理;水分胁迫下使用化学物质浸种提高了玉米幼苗的总根长,其中中度水分胁迫(ψs=0．4MPa)根长的增加幅度高于轻度水分胁迫(ψs=0．2MPa),前者增加的幅度为5．01％～50．83％,后者为0．32％～23．38％。与其他处理相比,水分胁迫下CCC ZnSO4处理的玉米幼苗的根长、根系干重和壮苗系数均较高,说明利用CCC ZnSO4处理具有促进根系生长,培育玉米壮苗的突出作用。     

干旱胁迫下保水剂对苗木生长及生理的影响

在盆栽条件下,对不同保水剂处理的土壤吸持水特性以及云南拟单性木兰和绒叶含笑苗的水分生理、生长状况进行试验研究。结果表明,随着保水剂用量的增加,土壤保水能力和供水能力增加,苗木在有限水分条件下生存期延长3-91 d,地径、树高、新增叶片分别增加了16.7％-461.2％,22.7％-368.2％,42.9％-372.7％;随着保水剂用量增加,土壤容重下降了6.2％-35.1％,总孔隙度和毛管孔隙度明显增加了3.6％-20.3％和5.9％-22.6％;在有限水分条件下,通过不同保水剂处理能减少水分的胁迫,净光合速率增长8.9％-461.2％,蒸腾速率增长了22.2％-518.7％,气孔导度增长了4.2％-512.5％。     

不同形态氮素营养对水稻抗旱性影响的研究

采用溶液培养方法,在不同水分胁迫强度下,分析不同氮素形态(铵态氮、硝态氮、铵硝混合态氮)对水稻生长状况与水分关系的影响.结果表明:在轻度水分胁迫(5%PEG,约相当于-0.05 MPa)条件下,供铵和供铵硝混合态氮水稻生物量高于正常水分条件下的相应供氮形态处理,说明适度水分胁迫可以刺激这2种供氮形态水稻的生长;在重度水分胁迫(10%PEG,约相当于-0.15 MPa)条件下,仅供铵态氮水稻生物量高于正常水分条件下的相应供氮形态处理.此外,在水分胁迫条件下,供铵态氮水稻根系总长、根表面积和根系体积受水分胁迫影响不明显.重度水分胁迫条件下,供铵态氮水稻单位茎截面积的伤流液流速、水分利用率等都显著高于其他供氮形态水稻.因此,与其他氮素形态相比,供应铵态氮可以增强水稻在干旱环境下的生长.     

局部根区水分胁迫下钙对冬小麦生长及养分吸收的影响

以小偃22为材料,采用Hoagland营养液进行分根培养试验,研究了局部根区水分胁迫下,钙对冬小麦幼苗生长及养分吸收的影响。设置2个钙水平处理(正常供钙和不供钙)、3种水分处理(正常水分、局部根区水分胁迫和全部根区水分胁迫),共6个处理。结果表明:不论是否水分胁迫,缺钙处理冬小麦幼苗的株高、主根长、生物量、叶绿素相对含量(SPAD值)、相对含水量及地上部N、P、Ca含量和根系N、P、K、Ca含量均显著低于正常供钙处理(P0.05)。正常供钙条件下,局部根区水分胁迫使株高增加4.4%,正常水分、局部根区水分胁迫和全部根区水分胁迫的植株生物量分别为1.54、1.66 g·株-1和0.97 g·株-1,比缺钙处理分别高19.4%、25.8%和4.3%;全部根区水分胁迫下,冬小麦的株高及主根长均显著降低。缺钙条件下,植株对N、P、Ca等养分的吸收显著降低。正常供钙条件下,正常水分、局部根区水分胁迫和全部根区水分胁迫处理地上部全氮含量分别为36.54、36.65g·kg-1和32.70 g·kg-1,比缺钙处理分别高9.5%、6.5%和6.9%;全磷含量分别为7.48、7.51 g·kg-1和6.54 g·kg-1,比缺钙处理分别高3.0%、13.1%和22.7%;全钙含量分别为8.35、8.37 g·kg-1和5.53 g·kg-1,比缺钙处理分别高26.5%、24.4%和19.7%。结果说明钙显著影响冬小麦幼苗生长发育和养分利用,钙可促进局部根区水分胁迫下冬小麦幼苗的生长及其对养分的吸收,缓解全部根区水分胁迫的抑制效应。     

局部高浓度硝酸盐供应对玉米根系 形态及氮累积的影响

以郑单958和鲁单981为研究对象，进行水培分根试验，在正常供水和水分胁迫条件下，分别以均匀低浓度硝酸盐处理主根和种子根(LPR-LSR)、局部高浓度硝酸盐处理主根（HPR-LSR）和局部高浓度硝酸盐处理种子根（LPR-HSR），测定分析根系形态、生物量以及氮含量。结果表明：与氮低效鲁单981相比，氮高效郑单958具有较高的主根根长、根表面积、根系生物量、地上部生物量和氮累积量。水分胁迫条件下，郑单958和鲁单981的主根的根长、根表面积、根体积、地上部生物量和氮累积量总体上均低于正常水分条件。玉米主根和种子根对局部高浓度硝酸盐的反应存在差异。与均匀低浓度硝酸盐处理相比，局部高浓度硝酸盐处理促进正常水分条件下主根和种子根根系的生长，尤其是根长和根系表面积；在正常水分条件下，主根根长和根系表面积增加幅度范围为6.8%~27.3%和1.9%~21.9%，除HPR-LSR处理条件下的郑单958外，种子根根长和根系表面积增加幅度范围为30.4%~92.7%和10.5%~135.1%；在水分胁迫条件下，主根根长和表面积增加幅度范围为24.6%~152.9%和62.1%~229.9%，然而种子根根长降低了10.0%~29.9%，表明水分胁迫会影响种子根对高浓度硝酸盐的响应。除水分胁迫条件下LPR-HSR处理外，局部高浓度处理可同时增加两侧根系的生物量和氮累积量。无论是正常供水还是水分胁迫，与LPR-LSR处理相比，局部高浓度硝酸盐供应均能够增加地上部生物量以及氮累积量，在LPR-HSR处理条件下，增加幅度范围分别在35.0% ~107.9%和162.9%~291.1%，在HPR-LSR处理条件下分别为56.7%~109.4%和204.1%~377.0%，HPR-LSR处理条件下增加幅度较大，表明在氮素非均匀分布环境中，当主根处于高浓度硝酸盐区域时将会更显著促进生物量的增加和氮累积。     

水分胁迫下AM真菌和根瘤菌对沙打旺生长及养分吸收的影响

利用温室盆栽试验研究水分胁迫下接种丛枝菌根（Arbuscular mycorrhizal,AM）真菌和根瘤菌（Rhizobium meliloti）对沙打旺(Astragalus adsurgens Pall.) 生长和养分吸收的影响。在土壤相对含水量65%和35%条件下,分别设不接种（对照）、单接根瘤菌、单接摩西球囊霉(Glomus mosseae)和双接根瘤菌与摩西球囊霉等4个处理。结果发现：干旱胁迫显著抑制沙打旺AM真菌侵染率（P<0.05）,而接种根瘤菌在两种水分条件下均显著促进摩西球囊霉对沙打旺根系的侵染（P<0.05）。接种AM真菌不仅显著提高沙打旺对P的吸收（P<0.05）,而且明显促进根瘤的生长。无论是在干旱条件下或是在正常供水条件下,双接根瘤菌与摩西球囊霉处理对沙打旺生长及养分吸收的效应显著高于单接菌处理,植株地上部、地下部生物量以及N、P、K等吸收量均为最大。结果表明：AM真菌与根瘤菌双接种技术在干旱、半干旱区受损生态系统的植被恢复中具有一定的应用潜力。     

沙芦内含物PAAC对干旱胁迫下玉米幼苗叶片光合及蛋白氧化损伤的保护作用

采用沙培试验,培养期间用沙丘芦苇特有的多氨基芳香族化合物PAAC水溶液对培养的两种不同基因型玉米幼苗叶片进行喷施处理,研究幼苗叶片在正常供水和干旱胁迫下的相对含水量、光合作用、叶绿素荧光等参数的变化趋势。确定这些生理指标在评价作物抗旱性方面的作用,并与甜菜碱溶液喷施处理的作物参比,研究该内含物对植物蛋白氧化损伤的影响。结果表明:PAAC溶液能够明显地降低干旱下植物叶片蛋白质中羰基含量的上升,即该内含物能够有效地减弱干旱胁迫下植物蛋白氧化损伤程度,RWC相对较高,说明PAAC一定程度上降低水分的散失。当植物受到中度干旱胁迫时,PAAC显著地减缓玉米叶片光合速率的下降,同时Fv/Fm、qP、ETR等叶绿素荧光参数数值也明显高于同期的对照,表明PAAC具有保护类囊体膜上PSⅡ的光合学活性的作用,一定程度上增强了植物的抗旱能力。     

黄土丘陵区垄沟改良措施对玉米水分利用效率的影响

选择延安地区作为黄土丘陵区的代表,在延安地区应用地膜、液态地膜、保水剂、PAM(土壤改良剂)和间作套种措施优化大垄沟种植方式种植玉米,分析了不同优化措施种植玉米的水分利用效率。结果表明,地膜、保水剂、PAM和间作方式有利于大垄沟较好地保持土壤水分,其保水能力分别比平种高出17.4%、8.5%、11.6%、5.3%;液态地膜、地膜、间作和PAM表现出很好的增产效果,其产量分别比平种高出77.7%、72.0%、64.1%、30.8%。     

Heterosis for water uptake by maize (Zea mays L.) roots under water deficit: responses at cellular,single-root and whole-root system levels

To examine the potential heterosis for water uptake by maize roots, the hydraulic properties of roots in the F1 hybrid (Hudan 4) were compared with those of its inbred parents (♂ 478 and ♀ Tian 4) at cellular, single-root and whole-root system levels under well-watered and water-deficit conditions. The cell hydraulic conductivity (Lpc) decreased under water deficit, but the Lp c of the F1 was higher than that of its inbred parents with or without stress from water deficit. Marked reductions in Lp c were observed following Hg2+ treatment. The hydrostatic hydraulic conductivity of single roots (hydrostatic Lp sr ) varied among genotypes under the two water treatments, with the highest in the F1 and the lowest in ♂ 478. Radial hydraulic conductivity (radial Lpsr ) and axial hydraulic conductance (Lax ) of the three genotypes varied similarly as Lpsr . The variations in hydraulic parameters were related to root anatomy. Radial Lp sr was negatively correlated with the ratio of cortex width to root diameter (R2=-0.77, P<0.01), whereas L ax was positively correlated with the diameter of the central xylem vessel (R2 =0.75, P<0.01) and the cross-sectional area of xylem vessels (R2 =0.93, P<0.01). Hydraulic conductivity (Lpwr ) and conductance (Lwr ) of the whole-root system followed the same trend under the two water treatments, with the highest values in the F1 . The results demonstrated that heterosis for water uptake by roots of the F1 occurred at cellular, single-root and whole-root system levels under well-watered and water-deficit conditions.     

Drought-induced anatomical changes in radish (Raphanus sativus L.) leaves supplied with trehalose through different modes

Leaf anatomical changes were appraised in exogenously applied trehalose of radish (Raphanus sativus L.) plants grown under nonstress (well-watered) and water stress (60% field capacity) conditions. Two cultivars of radish namely, Manu and 40-Day, were grown in a pot experiment at the Botanical Garden, GCUF, Pakistan. Plants were subjected to 60% field capacity conditions after three weeks of germination. Trehalose (25 mM) was applied to the radish plants through two different modes (foliar and presowing). After 2 weeks of foliar-applied trehalose, the leaves were excised from the plants for studying different anatomical features. Water stress caused a significant reduction in the leaf vascular bundle area, leaf midrib thickness (only in cv. Manu), leaf parenchyma cell area, and the number of vascular bundles in both radish cultivars, while water stress increased leaf epidermis thickness of both radish cultivars. Exogenously applied trehalose through both (presoaking and foliar spray) modes was effective in increasing leaf epidermis thickness, vascular bundle area, midrib thickness, and number of vascular bundles in both radish cultivars under water stress and nonstress conditions. Foliar-applied trehalose was more effective in increasing midrib thickness in both radish cultivars under both water regimes. Of both cultivars, the performance of cv. Manu was better in leaf epidermis thickness, leaf midrib thickness, vascular bundle area, leaf parenchyma cell area, and the number of vascular bundles. Overall, exogenous application of trehalose through both modes was effective in triggering leaf anatomical changes under different water regimes.     

夏玉米不同生育期对水分胁迫的生理反应与适应

利用大型活动遮雨棚池栽对夏玉米进行了出苗后的全程水分控制试验研究,探讨了不同生育期夏玉米叶面积、根系活力、叶片膜脂过氧化以及保护酶超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性对不同水分胁迫的生理反应与适应。结果表明:轻度受旱在大喇叭口至抽雄初期对植株叶面积影响不大,但抽雄后直至灌浆中期,轻度受旱持续时间长了也会对叶面积造成较大的不良影响。而重旱胁迫在各生育时期对叶面积的影响更为不利。干旱胁迫下,夏玉米生育进程中保护酶SOD、POD和CAT活性基本呈现一致下降的态势,膜脂过氧化作用增强,从而引发细胞内膜系统直接受损,可能是干旱逆境下作物主要的生理反应。各生育阶段因受旱时间和强度的不同,三个保护酶活性下降及膜脂过氧化产物丙二醛(MDA)积累均表现不同,随干旱胁迫的推进,短时期内对某些保护酶有一定的激发效应,即在大喇叭口期SOD和POD的活性有所增加,但此效应维持不长,其后骤降。受旱时间越长,受旱程度越重,则保护酶活性越低,MDA积累越多。根系对土壤干旱胁迫甚为敏感,玉米拔节期根系活力下降就见端倪,随受旱的延长及加剧将更加促使根系老化,根系活力快速衰减。     

逆境胁迫下镧对春小麦的影响

稀土元素镧处理使植物抗性增加，表现在：１。在盐胁迫条件下，镧可使植物的苗和根的长度，干重，鲜重，根体积，干／鲜比重，根，根／冠比增加。２．镧处理后植物对大量元素Ｎ，Ｐ，Ｋ，Ｃａ，Ｍｇ和微量元素Ｚｎ的吸收增加。在盐胁迫条件下镧对大量元素除Ｋ，Ｃａ外的其它元素都能起促进吸收作用。     

Influence of water stress on absorption, translocation and phytotoxicity of fenoxaprop-ethyl and imazamethabenz-methyl in Avena fatua

The influence of water stress on the absorption and translocation of ¹⁴C-labelled fenoxapropethyl and imazamthabenz-methyl in Avena fatua L. (wild oat) was studied. The phytoioxicity to A. fatua of both herbicides with a droplet application was also examined under water stress conditions. The absorption of both fenoxaproethyl and imazamethabenz-methyl was reduced by waler stress when the plants were harvested within 24 h after herbicide application. Up to 48 h after the application, the translocation out of the treated lamina of both herbicides, based on percentage of applied ¹⁴C. was reduced under water stress conditions. When havested 96 h after herbicide application, however, water stress no longer significantly affeaed the absorption and translocation of either herbicide. When the herbicides were applied as individual droplets, water stress reduced the phytotoxicity of fenoxaprop-ethyl but not that of imazamethabenz-methyl. It is concluded that the changes in herbieide absorption and translocation may not be the major physiological processes associated with differential whole-plant response oi A faiua to fenoxaprop-ethyl and imazamefhabenz-methyl under water stress.     

内陆石羊河灌区灌溉和施氮对夏玉米苗期生长及生理特性的影响

以夏玉米为材料,设4个灌水水平:337.5、6751、012.5、1 350 m3/hm2;4个施氮水平:75、150、225、300 kg N/hm2,研究限量灌溉和施氮对夏玉米苗期生长及生理指标的影响。结果表明:严重干旱会抑制玉米的生长。在玉米苗期,充分供水和高氮对玉米的生长不利,轻度亏缺与中氮组合使玉米苗期处于最佳生长状态,水氮共同作用对玉米的光合速率有促进作用;玉米苗期适度经受水分亏缺,有利于根系的生长;在同一施氮水平下,不同程度水分亏缺处理的根冠比(R/S)大于充分供水的处理。玉米苗期叶水势随灌水量的增大而增大,在灌水量相同时,叶水势随施氮量的增加而逐渐变大;干旱会使玉米光合速率下降,但适量增施氮肥可增加玉米的光合速率。     

土层水分非均匀供应下施锌对玉米植株中Ca、Fe、Mn、Cu吸收积累的影响

进行分层盆栽试验,模拟田间土壤剖面上下层水分不均匀分布条件,研究表层土壤施锌对玉米植株吸收Ca、Fe、Mn和Cu养分的影响。结果表明:上层土壤干旱抑制了苗期玉米植株生长,降低了地上部Ca、Fe、Mn分配比例。上层土壤干旱情况下,增加下层土壤水分供应,并没有提高植株生长和养分元素的吸收量。施锌明显促进了玉米地上部生长,在土壤水分充足时,施锌对植株生长效果更明显。不论土壤水分状况如何,施锌显著降低了植株中Ca、Fe、Mn、Cu浓度,对植株吸收积累Fe有拮抗作用;上层土壤干旱条件下,施锌还降低了地上部和整株中Mn以及根部Cu的积累量。施锌对植株体内Ca、Fe、Mn、Cu向上运输没有显著性影响。研究表明土壤表层干旱条件下,即使增加土壤水分,尚不能提高玉米植株生长和对Ca、Fe、Mn、Cu等养分的吸收利用。施用锌肥可以提高作物对土壤水分利用,但要注意对作物吸收Fe与Mn的拮抗作用,适当配合铁锰等养分供应。     

Spatio-temporal variation in transpiration responses of maize plants to vapor pressure deficit under an arid climatic condition

The transpiration rate of plant is physically controlled by the magnitude of the vapor pressure deficit(VPD) and stomatal conductance. A limited-transpiration trait has been reported for many crop species in different environments, including Maize(Zea mays L.). This trait results in restricted transpiration rate under high VPD, and can potentially conserve soil water and thus decrease soil water deficit. However, such a restriction on transpiration rate has never been explored in maize under arid climatic conditions in northwestern China. The objective of this study was to examine the transpiration rate of field-grown maize under well-watered conditions in an arid area at both leaf and whole plant levels, and therefore to investigate how transpiration rate responding to the ambient VPD at different spatial and temporal scales. The transpiration rates of maize at leaf and plant scales were measured independently using a gas exchange system and sapflow instrument, respectively. Results showed significant variations in transpiration responses of maize to VPD among different spatio-temporal scales. A two-phase transpiration response was observed at leaf level with a threshold of 3.5 k Pa while at the whole plant level, the daytime transpiration rate was positively associated with VPD across all measurement data, as was nighttime transpiration response to VPD at both leaf and whole plant level, which showed no definable threshold vapor pressure deficit, above which transpiration rate was restricted. With regard to temporal scale, transpiration was most responsive to VPD at a daily scale, moderately responsive at a half-hourly scale, and least responsive at an instantaneous scale. A similar breakpoint(about 3.0 k Pa) in response of the instantaneous leaf stomatal conductance and hourly canopy bulk conductance to VPD were also observed. At a daily scale, the maximum canopy bulk conductance occurred at a VPD about 1.7 k Pa. Generally, the responsiveness of stomatal conductance to VPD at the canopy scale was lower than that at leaf scale. These results indicate a temporal and spatial heterogeneity in how maize transpiration responses to VPD under arid climatic conditions. This could allow a better assessment of the possible benefits of using the maximum transpiration trait to improve maize drought tolerance in arid environment, and allow a better prediction of plant transpiration which underpin empirical models for stomatal conductance at different spatio-temporal scales in the arid climatic conditions.