珍珠绣线菊等7种园林树木光合、水分生理生态特性的研究

通过测定珍珠绣线菊等7种园林绿化树木小枝不同水分状况下的净光合速率、蒸腾速率变化,研究不同水分状况下7树种的光合生理生态特征,探讨其对水分胁迫的适应性。结果表明:随着小枝水分亏缺程度的加大,净光合速率呈下降趋势;随着小枝水分亏缺程度的加大其蒸腾速率呈下降趋势,二者关系曲线呈"S"型。初始失膨点总体渗透势(πp)、净光合速率水势补偿点值(ψnpc)、"S"型曲线近0拐点的水势(ψrtc)可用于评价树木对水分胁迫的适应性,其值愈小对水分胁迫的适应性越强,7种园林绿化树种对水分的适应性由强到弱顺序依次为:珍珠绣线菊、金焰绣线菊、金山绣线菊、栾树、金枝国槐、金叶莸、红王子锦带。     

几种针阔叶树种生长水势阈和生命水势阈的研究

为了研究树木生长水势阈和生命水势阈,在干旱、半干旱地区测定研究了樟子松、油松、侧柏、白扦、沙棘、新疆杨和白刺在不同水分状况下的吸水特征、光合作用年进程。结果指出树木生长水势阈和生命水势阈具有树种差异和树木年生长发育时期的变化,年生长末期较宽,对水分胁迫适应性强的树种较宽。嫩枝生长期各树种生长水势阈(Mpa)排序:侧柏>樟子松>油松>白刺>沙棘>白扦>新疆杨;各树种生命水势阈(Mpa)排序:沙棘>油松>白刺>樟子松>白扦>侧柏>新疆杨。     

科尔沁沙地樟子松人工林幼树水分生理生态特性

水分是沙地樟子松(Pinus sylvestris var. mongolica)生长最重要的生态因子,在对科尔沁沙地东南缘樟子松疏林草地土壤水分监测的同时,对13年生沙地(疏林草地)樟子松人工幼树的叶片水势(ψ)、蒸腾速率(E)、气孔导度(g)及其相应环境因子进行测定,探讨疏林草地人工樟子松幼树的水分生理生态特性.结果表明:蒸腾速率和气孔导度具有明显的日变化和季节变化规律,两者的变化趋势相似,即在生长季节樟子松蒸腾速率呈现出较明显的双峰曲线;影响其变化的主要内在因子为气孔导度,外在因子是空气湿度和气温.针叶水势在一定程度上受到降水量、土壤水分含量及树木本身生长特性的影响.樟子松针叶水势、蒸腾速率等水分生理生态特征表明,对于13年生沙地樟子松人工幼树(密度为378株/hm2),即使在年降水量较丰富的年份,疏林草地樟子松生长仍然受到一定程度的干旱胁迫.     

水分胁迫条件下冷暖型小麦幼苗期某些生理特性变化比较

采用溶液培养、PEG6000渗透胁迫处理等方法研究了不同温度型的小麦品种小偃6号(冷型)、陕229(冷型)和NR9405(暖型)在水分胁迫条件下,幼苗期小麦叶片中叶绿素含量、可溶性蛋白质含量、细胞膜相对透性、叶片相对含水量(RWC)、水势等生理特性的变化.结果表明:水分胁迫条件下,与暖型小麦NR9405相比,冷型小麦小偃6号和映229叶片中叶绿素和可溶性蛋白质含量下降缓慢,细胞膜相对透性较低,相对含水量(RWC)、水势较高.该结果说明,冷型小麦对于干旱的适应性较暖型小麦强.     

小麦由水分胁迫诱导的抗条锈性

 以一批在条锈病流行条件下具有保产能力的"耐病"品种和典型感病的小麦品种为试材,研究了病株水分关系的变化。结果发现,这些"耐病"品种具有水分胁迫所诱导的抗病性。在正常水分条件下呈亲和反应,但在水分胁迫时逆转为不亲和反应。病叶蒸腾作用在初期有轻微升高,其后病叶蒸腾速率、叶片扩散阻力、相对含水量和水势渐趋健叶水平,并具有较健叶更低的渗透势和更高的压力势,保持了有效的水分调控能力。而感病品种在水分胁迫时,病叶蒸腾速率急剧升高,叶片扩散阻力、相对含水量、水势、压力势和渗透势大幅降低,完全丧失了控制水分散失和维持水分平衡的能力。     

不同水分处理下冬小麦冠层温度、叶片水势和水分利用效率的变化及相关关系

小区栽培冬小麦,设计5种程度的干旱胁迫,利用防雨棚分别控制土壤重量含水量为田间持水量的45%、55%、65%、70%、80%,观测不同水分处理下冬小麦冠层温度、叶片水势和水分利用效率的变化及相关关系。结果显示,随着含水量的增加,各处理的平均和最高冠层温度整体呈下降趋势,叶水势和蒸腾速率呈上升趋势,在小麦抽穗期干旱胁迫最严重处理表现出最大水分利用效率,开花期的水分利用效率较抽穗期整体下降了50.70%;相关分析表明,抽穗期小麦的冠层温度与空气饱和差极显著正相关(P<0.01),开花期的冠层温度和叶水势呈显著负相关(P<0.05),冠层温度和空气饱和差存在着极显著正相关,空气饱和差和蒸腾速率极显著负相关,冠层温度和水分利用效率有着显著的正相关性。综上所述,冠层温度在小麦抽穗和开花期完全可以作为作物水分状况的有效监测指标之一。     

水分胁迫对葡萄光合特性的影响

以2年生盆栽葡萄品种品丽珠为试材,分别在50%、40%和30%的土壤最大田间持水量下进行水分胁迫后,测定其光合指标和光合色素含量的变化。研究表明,随胁迫时间的延长,净光合速率(P n)、蒸腾速率(T r)、气孔导度(G s)、胞间CO2浓度(C i)均呈下降趋势;葡萄光合能力随胁迫程度的加重而下降。叶绿素含量随胁迫时间延长和程度加深而降低,叶绿素a/b的值较稳定,类胡萝卜素的变化幅度相对较小。     

干旱胁迫下春小麦需水关键期叶水势的变化及其影响因素研究

揭示春小麦叶水势对水分胁迫的响应规律,在甘肃省定西干旱气象与生态环境试验站对春小麦在拔节~抽穗期进行水分胁迫试验,研究不同水分胁迫下春小麦叶水势的变化特征及其与环境因子的关系。结果表明: 随着水分胁迫程度的增强,春小麦叶水势呈逐渐减小的趋势,且不同水分胁迫下叶水势均表现为拔节期>孕穗期>抽穗期。春小麦叶水势对土壤体积含水率存在阈值反应,当土壤体积含水率＞11.5%时,叶水势随土壤体积含水率发生正相关变化;当土壤体积含水率＜11.5%则发生负相关变化。在众多环境因子中,大气相对湿度、大气水势与春小麦叶水势呈现出良好的线性关系。通径分析表明,影响轻旱处理下叶水势最强的因子是大气相对湿度,且大气相对湿度为51.87±0.03%时可作为轻旱处理下叶水势发生变化的临界阈值;中旱和重旱处理下影响叶水势的最强因子是大气水势,大气水势为-99.22±8.63 MPa时可作为中旱和重旱处理下叶水势发生变化的临界阈值。该研究为减轻春小麦受旱程度、维持春小麦正常生长及时补充水分提供理论依据。     

干旱胁迫对5个种源沙柳(Salix psammophila)气体交换及水分利用效率的影响

在盆栽条件下,对5个种源沙柳进行了水分胁迫处理,在不同干旱阶段对苗木叶水势、土壤含水率、蒸腾速率、光合速率等气体交换特性及水分利用效率进行了研究.结果表明:沙柳属于亚低水势忍耐脱水耐旱树种,叶水势随土壤含水量的下降而下降,变化趋势可用双曲线方程y=a b/x(0.389 0＜a＜0.520 3,8.906 6＜b＜11.466 9)拟合,其中民勤种源沙柳的双曲线方程中b值最低,为8.91,表现出较强的耐旱特性.在正常水分供应条件下,榆林种源沙柳的光合速率为23.89 μmol/(m2·s),水分利用效率为3.44 μmol/mmol,表现出很强的光合生产能力.随着干旱胁迫的加剧,各种源沙柳苗木的水分利用效率均有不同程度增加,民勤种源沙柳的增加值最大,为0.75 μmol/mmol,表现出了较强的抵抗干旱的能力,而榆林种源沙柳对水分亏缺则非常敏感,光合速率、蒸腾速率都急剧下降.这充分表明在水分供应充足的条件下,榆林种源沙柳具有最大的光合生产潜力;而当遇到干旱胁迫时,民勤种源沙柳则表现出极强的维持体内水分平衡的能力,是5个种源中最耐旱的种源.     

不同水分胁迫下的春小麦叶片气体交换参数和水分利用效率研究

叶片气体交换参数是作物产量形成的生理基础,其中光合速率和蒸腾速率决定了叶片水分利用效率,对作物抗旱节水研究具有重要意义。在定西和武威两个试验站进行春小麦盆栽水分模拟试验,设置对照(CK)、持续干旱(WS)、中旱(40%FC)和重旱(30%FC)4组处理,分析不同水分条件下春小麦叶片气体交换参数和水分利用效率(WUEinst)的变化特点及其相关特征。结果表明:(1)持续干旱胁迫下,春小麦的土壤日耗水量、光合速率、蒸腾速率和气孔导度均呈先快后慢的下降趋势,达到中旱和重旱水平时相比CK分别减小了71%和76%、39%和60%、57%和66%、60%和77%,受影响程度为:气孔导度蒸腾速率光合速率,胞间CO_2浓度在轻旱-中旱时下降,中旱后期降幅达33%,之后呈上升趋势,WUEinst在轻旱-中旱阶段上升,中旱后期时增加41%,之后下降,相比于CK,轻-重度胁迫会提高WUEinst,极度干旱则使之降低;(2)当水分胁迫维持在中旱或重旱水平时,以上各指标均会维持在持续干旱达到相同干旱等级时对应的值附近,且中旱时值均高于重旱时的数值(P0.05);(3)在持续干旱胁迫的轻旱-中旱阶段,净光合速率和蒸腾速率互为主导影响因子,而在持续干旱胁迫之后的阶段,以及胁迫维持在中旱或重旱情形下,两者的主导因子均为气孔导度,WUEinst在水分充足—持续干旱胁迫时均以蒸腾速率为主导因子,而当胁迫维持在中旱或重旱时其受叶片气体交换参数的调控作用不明显。本研究结果可为作物在不同干旱阶段和情形下采取适当措施进行抗旱节水提供参考依据。     

林木抗旱性生理指标及其在干旱区造林中应用研究

<正> 中国干旱半干旱区面积占全国面积的52.5%,半壁河山是以水分胁迫为主导限制因子的特殊生态区。为了提高这一地区的造林质量,选择旱生和抗旱性强的树种造林是主要造林技术之一。对于如何评价和比较林木的抗旱性,传统方法多采用对林木生态环境因子及对林木生     

偃麦草属植物种质材料不同耐盐群体生理指标分析

采用温室苗期模拟NaCl盐分胁迫方法,对来自于21个国家的偃麦草属8个植物种34份种质材料苗期的叶片相对含水量(RWC)、相对电导率(REC)、脯氨酸(Pro)、K+/Na +、相对生长速度变化率、耐盐系数、存活率和出现盐害到死亡时间等指标进行测定, 且将0.9%NaCl浓度下的各项生理指标变化率和生长指标测定值,利用欧氏最大距离聚类分析 ,将34份偃麦草属植物种质划分为3个耐盐群体(级别):即耐盐种质、中度耐盐种质、敏盐种质.在此基础上,对NaCl胁迫下的RWC、REC、Pro和K+/Na+等生理指标进行比较分析,结果显示:随着NaCl胁迫浓度的增加,不同耐盐群体的偃麦草属植物种质材料叶片的各项生理指标表现出不同的变化趋势,其中REC、Pro、Na+均呈逐渐增加趋势, 而K+、K+/Na+和RWC则呈逐渐下降趋势,但当NaCl浓度上升至1.2%时,与对照(CK)相比,耐盐种质的REC、Pro和Na+分别增加了121.83%、29.25倍和145.45%,K +、K+/Na+和RWC分别下降了26.89%、74.26%和16.40%;而敏盐种质的REC 、Pro和Na+分别增加了199.20%、75.45倍和617.86%,K+、K+/Na+和RW C分别下降了43.16%、93.55%和27.69%,中度耐盐种质的增加和下降幅度居于二者之间.     

不同扁蓿豆种质孕蕾期抗旱性综合评价

采用盆栽反复干旱法,在适度、中度和重度水分胁迫(土壤含水量分别为75%~80%、50%~55%和30%~35%)条件下,研究了12份不同生境扁蓿豆(Medicago ruthenica)种质孕蕾期的抗旱性。结果表明:随着干旱胁迫程度的加剧,12份扁蓿豆的绝对株高、茎粗、地上生物量、地下生物量、叶片相对含水量和叶绿素含量均呈下降趋势,而丙二醛(MDA)含量呈上升趋势;与对照相比,中度水分胁迫下,12份扁蓿豆叶片相对含水量的降幅均在11%以下,重度水分胁迫严重抑制了扁蓿豆的生长;中度和重度胁迫下,陇县扁蓿豆绝对株高降幅较小,分别下降了1.8%和22.1%;而渭源扁蓿豆叶片MDA含量在中度和重度水分胁迫下均比其他材料的含量高,分别为26.172μmol·g-1和31.149μmol·g-1。以中度和重度水分胁迫处理下绝对株高、茎粗、地上生物量、地下生物量、叶片相对含水量、MDA含量和叶绿素含量的相对值为评价指标,应用隶属函数法对12份扁蓿豆孕蕾期抗旱性进行综合评价,抗旱性强弱依次为:陕西陇县榆中永昌陇西天水渭源土默特自选8号景泰临夏镇原夏河。     

The influence of cyst nematodes and drought on potato growth. 2. Effects on plant water relations under semi-controlled conditions

Potatoes were grown under a permanent rain shelter in mobile containers in soil with and without potato cyst nematodes (Globodera pallida). The plants were either subjected to an early drought stress period from planting until 43 days after planting, to a late drought stress period during tuber bulking or to a drought control. Leaf water potentials, stomatal diffusion resistances for water vapour, transpiration rates, dry matter accumulation and water use efficiencies of the plants were determined periodically. Both drought and nematodes decreased leaf water potential and increased stomatal resistance.Drought led to a higher water use efficiency, cyst nematode infection, however, reduced the water use efficiency at early stages of growth, and increased it at later stages. It is concluded that at least two main growth reducing mechanisms exist of which the relative importance varies with time. Firstly, reduced apparent assimilation rates, which are unrelated to a change in the water balance caused by the initial attack by the cyst nematodes. Secondly, a reduced dry matter accumulation resulting from a decrease of water uptake. Effects of drought and cyst nematode infection on plant growth and water relations were not always additive mainly because infected plants used up less water leading to less drought stress.     

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。     

Unraveling Wheat Grain Quality,Physiological Indices,Dry Matter Accumulation,and Attenuating Water Stress Adverse Effect Via Foliar Potassium Application at Different Growth Stages

Water resources are increasingly scarce, and in drought prone production systems, the capability of the plant to recover its adverse effects is important for yield stability. There is an urgent need to develop water-saving strategies for wheat production. Water stress at critical growth stages diminishes wheat production and has harmful effects on crop growth and development; however, regulated water deficit and potassium foliar application ameliorates its adverse effect up to a certain extent. Consequently, the water deficit effect at different growth stages of the crop with exogenous application of potassium was evaluated in a screenhouse experiment in a complete randomized design (CRD) having four repeats. Varieties of wheat, i.e. Lalma (drought resistant) and Pakhtunkhwa-2015 (drought susceptible), were sown. Water deficit, i.e. mild water stress (50% of water required for field capacity) and severe stress (no application of water), at different growth stages of the crop were imposed. Potassium (K) foliar spray (1%) from potassium sulfate (K₂SO₄) was applied at the respective stage subjected to water deficit levels. Internal water status, i.e. relative water content (RWC) and water retention capacity (WRC), were attained maximum at tillering stage under mild stress than the rest of the stages with maximum for Lalma. Conversely, water saturation deficit (WSD) and water uptake capacity (WUC) were higher under severe stress imposed at grain filling stage. Theses indices were maintained by foliar potassium application. Similarly, dry matter (DM) allocation varied for stress level imposition and translocation to other parts were improved under foliar K application. The chlorophyll indices, i.e., soil plant analysis development (SPAD) value, also decreased with the severity of water deficit. Grain yield was higher under stress imposition at grain filling stage than the rest of the stages, though severe water stress decreased yield significantly. The Potassium (K) foliar spray showed no prominent effect at grain filling. Canopy temperature increased with stress severity and was maintained under K foliar spray. Osmotic adjustment, water and turgor potential were affected by water stress and maintained with foliar K spray. Grain quality and biochemical traits of wheat were affected severely under water deficit. Potassium foliar spray was found to decrease the adverse effect of the water stress and hence maintained the quality and biochemical characters. It is concluded that application of foliar potassium decreases the adverse effects of water stress at any growth stage, minimises the stress indices drastic effect and maintains the internal water balance of the crop at different stages subjected to water deficit.

     

华北平原滴灌条件下土壤水势对萝卜生长的影响

通过控制滴灌滴头下20cm深处土壤水势下限(-15kPa,N1;-25kPa,N2;-35kPa,N3;-45kPa,N4;-55kPa,N5),研究了不同处理土壤水势随时间和空间的变化规律,以及不同土壤水势处理对萝卜叶面积指数、叶绿素含量、周径膨大、干重积累等生长参数的影响,并对各处理间产量、水分利用效率进行了比较,发现在华北平原下半年降雨较多的情况下种植秋萝卜:(1)不同土壤水势处理对萝卜的生长发育没有明显影响;(2)不同处理水分利用效率不同:N5>N4>N3>N2>N1;(3)滴灌条件下,不同土壤水势处理萝卜的平均重量和产量都高于地面灌溉。     

An ecophysiological approach to crop losses,exemplified in the system wheat,leaf rust and glume blotch

Uninfected plants of spring wheat ‘Kolibri’ and plants infected with leaf rust were grown in a climate chamber at three soil-water potentials: ?1025 J.kg^?1 (D, ‘dry’, near wilting point), ?425 J.kg^?1 (M, ‘medium’, intermediate), and ?250 J. kg^?1 (W, ‘wet’, near saturation point). At lower water potentials plant development was faster, growth rate lower, and transpiration less than at higher water potentials. Growth and transpiration of plants at W were approximately twice those at D. Plants at M showed an intermediate response. Growth and yield of rusted plants grown at M were only slightly less than those of the uninfected controls, whereas at D and W considerable losses of plant dry weight and yield were caused by the rust. Infection type, pustule size and spore production were related to soil-water potential; at M, the pustules were smallest and the spore production was minimal. Results show a marked effect of soil-water potential on plant morphogenesis, and indicate that resistance of ‘Kolibri’ to leaf rust was related to soil-water potential. Optimal resistance was found at M, the intermediate soil-water potential.