外源ABA对渗透胁迫下玉米幼苗根系渗透调节的影响

用ABA处理不同抗旱性的两个玉米品种幼苗根系, 测定了根系的水势、渗透势、渗透调节能力及4种渗透调节物质的变化, 结果表明: 渗透胁迫条件下, ABA能提高根系的水势、降低渗透势、增加渗透调节能力, 且对抗旱性强的鲁玉14号的作用大于抗旱性弱的掖单13号. 正常供水条件下, ABA处理对根系水势的提高有一定的作用, 但对渗透势及     

渗透胁迫下不同玉米品种叶片水分关系的研究

通过盆栽及水培试验研究不同玉米品种在渗透胁下叶片的水分变化,结果表明：参试3个品种的气孔导度与光合速率、蒸腾速率均呈直线相关,但气孔导度对蒸腾速率的相关系数〉气孔导度对光合速率的相关系数;品种间气孔调节能力为农大60〉中单2号〉陕单911;陕单911的渗透调节能力〉中单2号〉农大60,陕单911能通过较低的渗透势和细胞内溶质含量的增加,维持细胞吸水,从而维持叶片较高的相对含水量和叶水势,并具有较高的膨压,维持细胞的延伸生长。3个品种的耐脱水干化能力不同,失水速度为陕单911〉农大60〉中单2号。     

干旱胁迫对玉米苗期生长和光合特性的影响

以2个不同抗旱性玉米品种郑单958 (抗旱性强)和陕单902 (抗旱性弱)为材料,采用盆栽控水试验,设置轻度干旱,中度干旱,重度干旱和正常灌水处理,研究了干旱胁迫对2个玉米品种植株生长、气体交换和叶绿素荧光参数的影响。结果显示,干旱胁迫抑制2个玉米品种植株生长和相对生长速率,导致整株生物量显著下降。随着干旱胁迫程度加剧,叶片最大净光合速率(P_nmax)、表观量子效率(AQY)、光饱和点(LSP)、气孔导度(G_s)、气孔限制值(L_s)、最大电子传递速率(ETR_m)、光能利用效率(α)、光系统II的实际量子产量(Φ_PSII)和光化学猝灭系数(q_P)均下降,而胞间CO₂浓度(C_i),光补偿点(LCP)和非光化学猝灭系数(q_N)均升高。可见,干旱胁迫下叶片光合能力和电子传递速率降低是2个玉米品种生物量减少的主要因素。但郑单958变化幅度小于陕单902,表明郑单958植株生长发育和光合特性比陕单902受干旱胁迫的影响小,较高的电子传递速率、较强的光能转化能力和较大的相对生长速率是郑单958适应干旱环境的重要生理特性。     

渗透胁迫下不同玉米品种叶片水分关系的研究

通过盆栽及水培试验,结果表明:参试三个品种的气孔导度与光合速率、蒸腾速率均呈直线相关,但气孔导度对蒸腾速率的相关系数﹥气孔导度对光合速率的相关系数;品种间气孔调节能力为农大60号>中单2号>陕单911;陕单911的渗透调节能力>中单2号>农大60号,陕单911能通过较低的渗透势和细胞内溶质含量的增加维持细胞吸水,从而维持叶片较高的相对含水量和叶水势,并具有较高的膨压,维持细胞的延伸生长。三个品种的耐脱水干化能力不同,失水速度为陕单911>农大60号>中单2号。     

苗期干旱胁迫条件下外源ABA对甘薯膜透性和抗氧化酶系统的影响（英文）

为了研究外源ABA对提高甘薯苗期抗旱性的影响,以抗旱品种济薯21和不抗旱品种济紫薯1号为试验材料,研究了苗期干旱胁迫条件下,外源ABA对甘薯渗透调节和抗氧化酶系统的影响。结果表明,胁迫处理12 d以后(AW),干旱胁迫处理(PEGW)的叶片相对电导率、叶片和根系的MDA含量均显著高于对照,根系活力则显著低于对照,抗旱品种和不抗旱品种表现相同的趋势;抗旱品种济薯21干旱胁迫处理(JS21-PEGW)的叶片和根系的SOD、POD和APX活性均显著高于对照(JS21-C),而不抗旱品种济紫薯1号(JZ1-PEGW)的叶片GR和根系APX活性则显著低于对照(JZ1-C);抗旱品种济薯21干旱胁迫处理(JS21-PEGW)的叶片和根系的抗氧化酶活性以及根系活力均显著高于不抗旱品种济紫薯1号(JZ1-PEGW),而叶片和根系MDA含量则显著低于济紫薯1号。胁迫处理12 d以后(AW),外源ABA显著降低了叶片相对电导率,抑制了叶片和根系中MDA的积累,提高了根系活力,提高了叶片和根系中SOD、POD、CAT、APX和GR的活性。因此,外源ABA在提高甘薯苗期抗旱性方面起着重要的作用,通过降低叶片相对电导率和MDA的积累而缓解膜的损伤,通过提高根系活力而提高根系的吸收能力,通过提高抗氧化酶活性而提高苗期叶片和根系的抗氧化酶系统的防御能力。     

玉米叶片光合作用和渗透调节对干旱胁迫的响应

以2个不同抗旱性玉米品种郑单958 (抗旱性强)和陕单902 (抗旱性弱)为材料,采用盆栽控水试验,设置3个干旱处理(轻度干旱、中度干旱、重度干旱)和正常灌水,研究了干旱胁迫对2个玉米品种气体交换、叶绿素荧光参数和渗透调节物质的影响。结果显示, 重度干旱造成2个玉米品种叶片光合机构紊乱,破坏细胞膜完整性;同时增加了渗透调节物质,这对增强叶片的保水能力,维持光合速率有重要的作用。但与陕单902相比,干旱胁迫下郑单958表现出较高的最大净光合速率(P_nmax),表观量子效率(AQY),光饱和点(LSP),最大电子传递速率(J_max),最大羧化速率(V_cmax),PSII的实际量子产量(Φ_PSII)和光化学猝灭系数(q_P);较高的脯氨酸(Pro)和可溶性糖含量(SS);较低的丙二醛含量(MDA)。这些结果表明,干旱胁迫下抗旱品种郑单958具有较强的渗透物质能力,减轻细胞膜质过氧化程度,维持较高的光合性能是其适应干旱环境的生理基础。     

玉米萌芽期抗旱性鉴定研究

通过种子萌发试验,以8个玉米品种（郑单958、豫单998、超越1号、浚单20、中科4号、洛玉4号、农大108、先玉335）为试验材料,研究了玉米萌芽期渗透胁迫对玉米萌发状况的影响。分析表明：在渗透胁迫条件下,发芽率降低,胚根、胚芽的生长受到不同程度的抑制,贮藏物质转运效率降低。其中发芽率和胚根干重与萌发抗旱指数呈极显著正相关,可作为萌芽期抗旱性鉴定的一级指标;胚根长、胚芽长与萌发抗旱指数呈正相关可作为萌芽期抗旱性鉴定的二级指标;胚芽干重与贮藏物质与萌发抗旱指数有一定的相关性但未达显著,可作为萌芽期抗旱性鉴定的三级指标。鉴定玉米萌芽期抗旱性以萌发抗旱指数为主,结合其他6项指标进行综合评价。     

土壤水分胁迫对冬小麦叶片渗透调节及叶绿体超微结构的影响

土壤水分胁迫下 ,抗旱性强的小麦品种昌乐 5号、北农 2号与抗旱性弱的济南 13、鲁麦 5号相比 ,渗透调节能力高 0 4 1～ 0 60MPa ,相对含水量少降 6 39～ 10 74个百分点 ,叶水势少降 0 19～ 0 63MPa。水分胁迫使小麦叶片光合能力下降 ,水分胁迫全过程下降平均百分数 ,抗旱性强的品种比抗旱性弱的品种光合速率少降 17 7%～ 2 2 5% ;气孔导度少降 2 1 0 6%～2 3 75%。小麦叶肉细胞叶绿体的超微结构发生变化且随水分胁迫的加重而加剧 ,但变化程度与小麦的抗旱性及渗透调节能力成负相关。胁迫导致叶绿体外形变圆 ,类囊体肿胀 ,片层间距加大 ,基质片层模糊 ,最终叶绿体解体     

水分胁迫下葡萄糖对小麦幼苗光合作用和相关生理特性的影响

以15%聚乙二醇(PEG-6000)模拟水分胁迫,以不同浓度外源葡萄糖(Glc)处理小麦幼苗,探讨外源Glc对水分胁迫下小麦幼苗生长发育和光合特性的影响。结果表明,水分胁迫显著降低了小麦叶片水势和光合作用,抑制植株的生长,而水分胁迫下外源Glc处理能明显增加叶片水势和光合色素含量,并使水分胁迫和水分胁迫后复水处理条件下,小麦幼苗叶片的净光合速率(P_n)、气孔导度(G_s)胞间CO₂浓度(C_i)和叶片水分利用效率(WUE)显著升高,而使蒸腾速率(T_r)下降。同时,外源Glc处理显著提高了水分胁迫下叶片中可溶性糖和脯氨酸的积累,促进不定根和侧根的生长,植株干重比单一干旱处理提高14.32%~40.39%。由此表明,水分胁迫下外源Glc通过促进小麦根系生长和提高叶组织的渗透调节能力,改善叶片的水分状况,提高了叶片的光合功能,促进小麦幼苗的生长,降低了水分胁迫对小麦幼苗生长的抑制作用。     

干旱胁迫下外源钙对棉花幼苗抗旱相关生理指标的影响

为研究外源钙对棉花抗旱性的作用机理,利用控制溶液渗透势(含和不含0.2 kg/L PEG-6000)与不同钙量的方法研究了正常水分和干旱胁迫下钙素对棉花幼苗的生理影响。结果表明,在相同硝酸钙条件下,干旱胁迫下棉花幼苗叶片膜透性、超氧自由基产生速率、MDA和POD活性高于正常水分,而叶片相对含水量和根系活力低于正常供水;无论在正常水分还是干旱胁迫下,均表现出随Ca2+浓度增加,叶片膜透性、超氧自由基产生速率、MDA呈下降趋势,叶片相对含水量和根系活力及POD活性呈上升趋势,但正常供水条件下生理指标变化较小。     

Intact Plant, Callus and Field Grain Yield Responses of Tepary Bean to Drought

In a field trial involving four tepary lines (Phaseolus acutifolius A. Gray), NE#8A and NE#19 produced higher grain yield than NE#5 and NE#7 under both well watered and drought conditions. However, NE#8A is considered more resistant than NE#19 in terms of drought sensitivity index. Greenhouse investigations on intact plants indicated no differences among the four lines in leaf and stem dry mass, and leaf area. Root depth did not strictly differentiate lower‐yielding from higher‐yielding lines. In contrast to lower‐yielding lines, however, plants of higher‐yielding ones allocated greater dry matter (DM) in roots in response to imposed water stress. Distinctly, NE#19 had the greatest root : shoot (R : S) while NE#8A characterized by high net photosynthesis. Both NE#8A and NE#19 showed reduced leaf area : root dry mass ratio, stomata conductance and transpiration rate. Consequently, these two lines showed no significant changes in leaf relative water content while photosynthetic water‐use‐efficiency increased in response to water stress. Calli derived from leaf and root tissues of higher‐yielding lines exhibited low initial osmotic potential (ψ_s). These calli did not show alterations in ψ_s, DM% and relative growth rate (RGR) when subjected to water stress. Although leaf‐ and root‐derived calli of lower‐yielding lines exhibited osmotic adjustment, they suffered water stress in terms of elevated DM and reduced RGR. Overall, results suggest that dehydration‐avoidance mechanisms conditioned by increased root mass and stomata resistance accompanied with low initial cellular ψ_s sustained high grain yield of tepary under limited water supply.     

渗透胁迫对小麦幼苗生长及水分状况的影响

以耐旱性不同的小麦品种长武134和陕253作为实验材料,研究了PEG-6000模拟干旱水培实验条件下小麦幼苗生长以及水分状况的影响。研究结果表明,在渗透胁迫过程中,两个小麦品种的相对水分含量、水势、叶面积都呈降低的趋势,根系长度、根系面积以及根冠比呈现增加后降低的趋势,陕253在胁迫24h时达到最高值,长武134胁迫30h时达到最高,然后又降低.叶绿素a和叶绿素b的含量在受到胁迫30h之前变化不明显,继续胁迫其含量会急剧下降。说明轻中度干旱并不会影响叶绿素的含量。     

Effect of Water Stress on Physiological Attributes and their Relationship with Growth and Yield of Wheat Cultivars at Different Stages

The effects of water stress on physiological attributes of drought‐sensitive (Kalyansona) and drought‐tolerant (C‐306) wheat cultivars were studied in a pot experiment. Water stress was imposed by withholding irrigation at boot and anthesis stages. Leaf water potential, leaf osmotic potential and leaf turgor potential (measured with pressure chamber and osmometer), as well as leaf diffusive resistance, leaf transpiration rate and leaf‐to‐air transpiration gradient (measured with a steady‐state porometer) were measured diurnally. Growth and yield parameters were recorded after harvesting of the crop. Triplicate data were analysed using a completely randomized design and correlations amongst these parameters were computed. Water stress was found to reduce diurnal leaf water potential and leaf osmotic potential in both the genotypes but leaf osmotic potential was significantly higher in the drought‐tolerant cultivar C‐306 than in the drought‐sensitive cultivar Kalyansona. Positive turgor was recorded in both the genotypes under water stress and non‐stress conditions. Water‐stressed plants showed significantly lower turgor potential than control plants. In diurnal observations, water‐stressed plants exhibited significantly higher leaf diffusive resistance in both genotypes at both stages. The diffusive resistance of C‐306 was predominantly higher than that of Kalyansona. Water stress decreased leaf transpiration rate at both stages but the reduction was higher at the anthesis stage. The leaf‐to‐air temperature gradient was much higher in C‐306 than in Kalyansona at the boot stage but at the anthesis stage genotypic variation was non‐significant. The capacity to maintain cooler foliage was lower at the anthesis stage than at the boot stage in both the cultivars. Shoot dry weight, number of grains, test weight, grain yield, biological yield and harvest index decreased to a greater extent when water stress was imposed at the anthesis stage, while imposition of water stress at the boot stage caused a greater reduction in plant height and number of tillers. Similarly, water stress caused a smaller reduction in growth, yield and yield attributes in C‐306 than in Kalyansona. In general, the correlation coefficient of grain and biological yield with water potential and its components was positive and highly significant. Similarly, turgor potential was also correlated positively and significantly with grain yield at both the stages, but with biological yield it was significant only at the anthesis stage. A negative and significant correlation was obtained for diffusive resistance and leaf‐to‐air temperature gradient with grain yield at the boot and anthesis stages. The rate of transpiration was also positively and significantly correlated to grain and biological yields at both the stages. Amongst the yield attributes, number of leaves and number of tillers were positively correlated at the anthesis stage, whereas leaf area and shoot dry weight were significantly correlated with grain and biological yields at both the stages.     

Atmospheric and soil water deficit induced changes in chemical and hydraulic signals in wheat (Triticum aestivum L.)

Plant responses to soil drying and the metabolic basis of drought-induced limitations in stomatal opening are still being discussed. In this study, we investigate the roles of root-born chemical and hydraulic signals on stomatal regulation in wheat genotypes as affected by soil drought and vapour pressure deficit. Twelve consecutive pot experiments were carried out in a glasshouse. Two bread wheat cultivars (Gönen and Basribey) were subjected to drought under high and low vapour pressure deficit (VPD) in a growth chamber. Total dry matter, specific leaf area, xylem ABA content, xylem osmotic potential, xylem pH, root water potential (RWP), stomatal conductance, leaf ABA content and photosynthetic activity were determined daily during 6 days after the onset of treatments (DAT). In the first phase of drought stress, soil drying induced an increase in the xylem ABA with a peak 3 DAT while RWP drastically decreased during the same period. Then the osmotic potential of leaves decreased and leaf ABA content increased 4 DAT. A similar peak was observed for stomatal conductance during the early stress phase, and it became stable and significantly higher than in well-watered conditions especially in high vapour deficit conditions (H-VPD). Furthermore, xylem pH and xylem osmotic potential appeared to be mostly associated with atmospheric moisture content than soil water availability. The results are discussed regarding possible drought adaptation of wheat under different atmospheric humidity.     

甜菜幼苗光合生理对干旱胁迫的响应

干旱胁迫是抑制甜菜生长发育和影响产量的重要非生物因素。以耐旱型甜菜种质依安一号（V1）和干旱敏感型种质92011/1-6/1（V2）为试验材料,探讨不同耐旱品种甜菜幼苗光合生理对干旱胁迫的响应。研究了干旱胁迫对甜菜幼苗生长发育、总叶绿素含量和表观光合指标的影响。结果表明,干旱胁迫下2种甜菜幼苗的茎粗、根长、株高、叶鲜重、根鲜重、叶干重和根干重均呈下降趋势,V1下降幅度不明显且各指标降低幅度均小于V2;干旱胁迫降低了2种甜菜幼苗的叶绿素含量,叶绿素含量在第7天降到最低,且V1的含量明显高于V2;干旱胁迫使甜菜幼苗的净光合速率、蒸腾速率、叶片气孔导度和胞间CO₂浓度显著下降,V1受到的影响比V2要小。不同耐旱性甜菜品种对干旱胁迫的响应机制存在一定差异,可以进一步分析其抗旱能力,为甜菜的育种、抗逆栽培和稳产提供理论依据。     

水分胁迫对糜子植株苗期生长和光合特性的影响

选取耐旱性不同的糜子品种陇糜4号(强抗旱)、晋黍7号(旱敏感)和5283黄(中等抗旱),采用盆栽控水试验,调查不同水分处理对糜子苗期主要性状和光合参数的影响。结果表明：(1)水分胁迫下各品种的株高、叶面积、根重、叶绿素含量、根系活力均呈下降趋势,且陇糜4号的降幅小于5283黄和晋黍7号。(2)水分胁迫下,3个品种的固定荧光值(F_o)和非光化学猝灭系数值(q_N)均显著增加,在重度胁迫后,陇糜4号、5283黄和晋黍7号的F_o值分别比对照增加24.6%﹑34%和40.8%,q_N值分别增加0.956、1.083和2.183,且表现为旱敏感品种晋黍7号的增加幅度大于强抗旱品种陇糜4号;各品种的可变荧光(F_v)、最大荧光(F_m)、最大光化学量子产量(F_v/F_m)、PSII的潜在活性(F_v/F_o)、光化学猝灭系数(q_P)值均因水分胁迫而降低。在中度和重度胁迫时,与正常灌水相比差异达显著水平,降幅以晋黍7号>5283黄>陇糜4号。(3)各品种的净光合速率、蒸腾速率、气孔导度及胞间CO₂浓度均因水分胁迫而下降,强抗旱品种陇糜4号各值的变化幅度均小于中等抗旱品种5283黄和旱敏感品种晋黍7号,表明陇糜4号的光合参数受水分胁迫的影响最小,较高的电子传递速率和较强的光能转化能力是陇糜4号适应干旱环境的重要生理特性。(4)水分胁迫导致糜子叶片对强光的敏感性增加,干旱和光抑制对光系统II造成的叠加伤害随干旱加重和品种抗旱性减弱而加剧,因此,对强光下的糜子幼苗应及时补水,以避免干旱和高光强的叠加伤害。     

谷子苗期对不同程度干旱胁迫的响应及抗旱性评价

以6份谷子材料为研究对象,研究了不同程度干旱胁迫（设水分充足、中度干旱、重度干旱3个处理）对谷子苗期生长及根系形态特征的影响,并进行了抗旱性鉴定。结果表明,谷子在水分充足条件下生长最好,随着干旱胁迫的加强,谷子的株高、顶三叶叶面积、根长、根表面积、根体积、根尖数均呈下降趋势。山西2010在中度干旱和重度干旱胁迫下根冠比增加的幅度均最大,分别为15.95%和25.36%,抗旱性较好。     

干旱胁迫下不同小豆品种根系生长规律研究

采用盆栽人工控水的方法,研究不同小豆品种根系对干旱胁迫的响应。结果表明,干旱胁迫抑制了小豆根系的生长,随着干旱胁迫的加剧,小豆的最大根长呈先增加后减少的趋势,根重、总根长、根表面积、根体积、株高、茎粗和叶面积呈减小的趋势,根冠比呈增加的趋势;不同品种小豆对干旱胁迫的响应存在差异,抗旱型品种的根重、总根长、根表面积、根体积、株高、茎粗和叶面积随干旱胁迫的加剧下降幅度小,根冠比显著加大。重度干旱胁迫下,品种间最大根长、根重、根体积、株高、茎粗、叶面积和根冠比差异在整个生育期间达显著水平。抗旱型品种冀红8937的根系更为发达,根冠比较高,中度干旱胁迫下,最大根长的增加幅度较大,随着干旱胁迫的加剧,其根重、总根长、根表面积、根体积、株高、茎粗和叶面积下降幅度较小,根冠比显著增加。     

类芦根系对不同强度干旱胁迫的形态学响应

为了探讨类芦根系对干旱胁迫逆境的响应规律,为其在水土流失区推广和应用提供科学理论依据,以水土保持先锋植物类芦为研究对象,通过4个不同干旱强度胁迫的盆栽试验,测定不同干旱处理对类芦根系生物量和根系形态指标。结果表明：不同干旱强度胁迫处理,类芦根系总长度、表面积、平均直径、根系生物量的差异明显,而根体积差异较小。在不同程度干旱胁迫下,根体积、根平均直径随着干旱胁迫程度增加逐渐减小,且均比充足供水的小;而类芦根系总长度、根表面积、根系生物量、根冠比均比充足供水的大,中度干旱胁迫条件下（田间持水量40%±5%）,类芦的根系长度、根表面积、根系生物量、地上部生物量、根冠比均为最大。类芦具有庞大的根系,抗旱和耐旱能力强;类芦根系增强延伸能力、扩大与土壤接触面积是对干旱逆境的形态学响应机制之一。