水培条件下营养元素对枳幼苗根毛发育及根生长的影响

以柑橘砧木枳实生苗为试材,研究水培条件下N、P、K、Ca、Mg、Fe和Mn等7种营养元素分别缺乏对其根系主根长度、侧根数和主、侧根根毛密度、根毛长度及根毛直径等的影响.结果表明:水培条件下,不同缺素处理枳实生幼苗的根毛均能生长,但根毛主要集中在近根基段,根尖处分布较少;侧根的根毛密度显著大于主根,而其根毛长度显著小于主根.不同缺素处理对根毛的生长发育影响较大,主根根毛密度为55.0～174.3条·mm-2.与对照相比,缺Ca诱发主根的根毛密度、长度显著增加;缺P使主根的根基段、中段及侧根的根毛密度、长度显著增加;缺Fe使主根根尖段根毛密度显著增加,而长度显著降低;缺K使主根、侧根的根毛密度、长度及根毛直径均显著降低;缺Mg使主根根毛长度显著增加.各处理主根的生长较一致;侧根除缺N、Mg处理外,其他处理均出现脱落后再生的现象.     

水培条件下营养元素对枳幼苗根毛发育及根生长的影响

以柑橘砧木枳实生苗为试材,研究水培条件下N、P、 K、Ca、Mg、Fe和Mn等7种营养元素分别缺乏对其根系主根长度、侧根数和主、侧根根毛密度、根毛长度及根毛直径等的影响．结果表明: 水培条件下,不同缺素处理枳实生幼苗的根毛均能生长,但根毛主要集中在近根基段,根尖处分布较少;侧根的根毛密度显著大于主根,而其根毛长度显著小于主根.不同缺素处理对根毛的生长发育影响较大,主根根毛密度为55.0~174.3 条·mm^-2．与对照相比,缺Ca诱发主根的根毛密度、长度显著增加;缺P使主根的根基段、中段及侧根的根毛密度、长度显著增加;缺Fe使主根根尖段根毛密度显著增加,而长度显著降低;缺K使主根、侧根的根毛密度、长度及根毛直径均显著降低;缺Mg使主根根毛长度显著增加．各处理主根的生长较一致;侧根除缺N、Mg处理外,其他处理均出现脱落后再生的现象.     

花铃期棉花对棉蚜刺吸胁迫的生理响应

为了探索棉花对棉蚜Aphis gossypii Glover胁迫的抗性机理,利用分光光度计法测定了花铃期棉花经棉蚜刺吸后的生理指标。结果表明:在棉花花铃期,叶绿素含量在处理前期均有上升情况,仅在处理第10天后,蚜虫密度80头处理下的叶绿素含量显著低于对照;随着取食时间延长,各蚜虫密度下的可溶性蛋白含量均有所增加,并在处理10 d后,蚜虫密度80头处理下的可溶性蛋白含量显著比对照增加了78.38%;而游离脯氨酸、丙二醛含量随着取食时间增加呈先升后降的趋势,且在取食前期随着蚜虫密度增加,脯氨酸、丙二醛含量逐渐上升。由此可知,棉花能忍耐低密度蚜虫胁迫,而较高密度蚜虫刺吸初期敏感,随着胁迫时间延长,其自身防御能力增强。     

黄芪幼苗对镉胁迫的生理响应机制

以我国传统药用植物黄芪(Astragalus membranaceus(Fisch.)Bunge)幼苗为材料,在水培条件下系统研究了不同程度Cd胁迫对黄芪生长发育、矿质元素吸收转运以及次生代谢产物积累的影响。25~200μmol·L^-1Cd处理显著抑制了黄芪幼苗根系和地上部的生长并引起了植株MDA含量的显著升高以及新生叶片光合色素含量的降低,表明Cd处理对黄芪幼苗造成了较为明显的伤害。植株中吸收的Cd主要积累在黄芪幼苗根系,而运输到地上部的Cd积累规律为顶端<中部<基部,显示出黄芪幼苗可以通过对Cd的区域化降低其在地上部新生组织的积累。Cd处理降低了植株对多种矿质营养元素的吸收和转运,但是Ca和Mg却分别在地上部顶端和基部出现了明显的含量升高,推测其可能与降低Cd在新生组织的毒害作用以及提高老叶的Cd耐性有关。此外,根系中4种异黄酮物质的含量在Cd处理下明显升高,黄芪皂苷Ⅰ-Ⅳ的含量则被Cd处理所降低,暗示着异黄酮而非皂苷类物质在黄芪幼苗根系应对Cd胁迫中发挥了积极作用。     

棉花花铃期短期干旱下氮素对干物质及氮素累积分配的影响

通过盆栽试验进行水分(正常灌水和干旱后复水)和施氮处理(0、240、480kgN·hm-2),研究花铃期短期干旱再复水后氮素对棉花各器官干物质重、氮素累积与分配及产量与品质的影响.结果表明:花铃期土壤干旱显著降低了棉株各器官的干物质重与氮素累积量,而增大了棉株各器官的氮素含量,同时亦降低了棉株干物质与氮素在叶片中的分配指数,但提高了在根系的分配指数,从而增大了根冠比;增施氮肥可以提高干旱条件下棉株的干物质重与氮素累积量,但亦增大水分胁迫指数.复水对干旱处理棉株生长具有明显的补偿效应,尤其是根系的干物质重与氮素累积量显著高于相应正常灌水处理,且增施氮肥可以提高棉株的补偿效应.花铃期干旱结束时与复水后第10天,干旱处理棉株均以240kgN·hm-2水平下的生殖器官干物质重与分配指数最高,而根冠比最小,地上部与地下部生长最为协调,最终籽棉产量最高、纤维品质最优;而施氮不足(0kgN·hm-2)或过量(480kgN·hm-2)均不利于棉花产量的提高与纤维品质的改善.     

辣椒开花结果期对干旱胁迫的形态与生理响应

在遮雨网室选用抗旱性较强的农城椒二号和抗旱性较弱的陕蔬2001,研究辣椒在轻度、中度和重度干旱胁迫下不同时间的生长、产量、渗透调节物质、保护酶活性的变化规律及其生理调节机制。结果表明:随干旱胁迫时间的延长,辣椒的株高、分枝数、叶面积、单位面积产量、叶绿素含量和叶片相对含水量的抗旱系数呈下降趋势,下降速率与干旱胁迫程度呈正相关,与品种的抗旱性呈负相关;脯氨酸、丙二醛含量和细胞膜透性相对值随干旱胁迫时间的延长呈上升趋势;POD、SOD、CAT活性和可溶性蛋白相对值随着干旱胁迫时间的延长先升高后下降,抗旱性强的材料增加幅度低于抗旱性弱的材料;可溶性糖含量的相对值在轻度和中度干旱胁迫下呈上升趋势,在重度干旱胁迫下呈上升—下降趋势,且抗旱性强的材料上升速度大于抗旱性弱的材料。相关分析表明,干旱胁迫下,产量与株高、分枝数、叶片叶绿素含量、叶面积、叶片相对含水量抗旱系数呈显著正相关;与细胞膜透性、CAT活性和可溶性蛋白含量抗旱系数呈显著负相关。主成分分析表明,用作辣椒抗旱性鉴定的主要指标是单株产量、株高、叶面积、分枝数、可溶性蛋白、可溶性糖、MDA、叶绿素含量和细胞膜透性及叶片相对含水量,叶片POD、SOD、CAT活性、脯氨酸含量可做为辣椒抗旱性鉴定的次要鉴选指标。     

黄连木对干旱胁迫的生理响应

研究了自然干旱条件下黄连木（Pistacia chinensis Bunge）的生理变化。结果表明,随土壤含水量的减少,叶绿素b含量、光合速率、叶片相对含水量与叶水势均下降;叶绿素a和可溶性糖含量、叶绿素a和b的比值及总叶绿素含量呈现上升的趋势;超氧化物歧化酶活性先升后降;丙二醛含量干旱胁迫前期升高,后期变化不明显;净光合速率、气孔导度和蒸腾速率随土壤含水量的减少逐步降低。气孔和可溶性糖含量都是影响黄连木光合速率的关键因子,干旱胁迫前12d光合速率主要受气孔限制,之后为非气孔限制。干旱胁迫前期渗透调节物质以可溶性糖为主,干旱胁迫较重时脯氨酸含量急剧升高,与可溶性糖同时起渗透调节作用。     

两个不同耐旱性棉花品种根系生理特性对干旱的响应

为探明不同抗旱性棉花品种的根系生理特性对干旱的响应及其与生物量的关系,以不耐旱性品种‘新陆早17号'(L17)和耐旱性品种‘新陆早22号'(L22)为试材,在土柱栽培条件下设常规灌溉(CK)、轻度干旱(W₁)和中度干旱(W₂)处理,研究干旱胁迫对不同耐旱性棉花品种根系活力、保护酶活性及解剖结构(导管直径、数量)和生物量的影响。结果表明:干旱胁迫下两棉花品种根系可溶性蛋白(SP)含量、根系活力(RV)、木栓层数、根茎导管数量、导管直径显著降低,根系丙二醛(MDA)含量及保护性酶活性显著增加,进而导致地上部干物质量显著降低。与L17相比,L22的SP含量、0～40 cm和80～120 cm土层RV、木栓层数、根茎导管数量、导管直径以及地上部干物质量均显著增加,尤其W₂条件下L22的RV降幅比L17低26.2%,过氧化氢酶(CAT)、过氧化物酶(POD)和超氧化物歧化酶(SOD)活性和皮层厚度分别比L17高43.6%、6.9%、25.4%、19.9%,且差异均达到显著水平。干物质量与RV、SOD、POD、木栓层数、导管直径和个数之间均呈显著正相关。因此,耐旱性强的棉花品种在干旱条件下通过保持较高的根系活性、木栓层数、导管直径和数量,进而促进地上部生物量积累,是其具有较高耐旱性的生理机制。     

转基因烟草在PEG6000模拟干旱胁迫条件下的生理响应

该研究以转高山离子芥的CbPLDα、CbPLDβ基因烟草为材料,研究了渗透调节物质和保护酶系对PEG6000溶液模拟干旱胁迫的响应机制.结果表明:渗透调节物质脯氨酸、可溶性糖、可溶性蛋白分别以各自不同的响应方式在干旱胁迫下增强转基因烟草的抗旱性,且在所有浓度PEG6000模拟的干旱胁迫下,转基因烟草的脯氨酸、可溶性糖、可溶性蛋白的含量始终显著高于野生型烟草(P<0.05).说明干旱胁迫下两种转基因烟草的渗透调节能力要强于野生型烟草.保护酶系中,超氧化物歧化酶(SOD)和过氧化物酶(POD)在减轻干旱胁迫下转基因烟草膜脂过氧化伤害中起到协同互补作用,而过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)在干旱胁迫下转基因烟草清除过氧化氢机制中发挥主要作用,说明保护酶系在抵制干旱胁迫和保护转基因烟草免受干旱伤害方面具有重要的生物学功能,这从生理角度揭示了高山离子芥CbPLDα、CbPLDβ响应干旱的生理生态机理.综上,高山离子芥CbPLDα、CbPLDβ基因参与了干旱胁迫下烟草的膜稳定性调节、渗透调节物质的积累和抗氧化酶系的调控.该研究结果为提高植物抗旱性研究及应用提供了新的基因资源,对于加强PLD功能研究、补充植物抗干旱理论及抗低温干旱育种种质资源的开发利用具有重要意义.     

谷子对干旱胁迫的生理生态响应

干旱少雨严重限制了我国西北地区谷子的产量,为明确谷子响应干旱的生理特征,以干旱敏感谷子品种安04和不敏感品种豫谷1号以及xiaomi为材料,通过盆栽试验,研究了谷子不同生育期叶片光合参数、叶绿素含量、非结构性碳、β-淀粉酶基因表达对水分亏缺的响应。结果表明,正常水分条件下安04产量高于豫谷1号,干旱胁迫严重限制了两个谷子品种的产量形成,安04和豫谷1号分别减产71.2%和56.0%,豫谷1号产量显著高于安04。正常水分条件下,安04具有比豫谷1号更高的净光合速率（P<0.05）,干旱胁迫下,豫谷1号叶片净光合速率显著高于安04;叶片蒸腾速率结果同光合结果一致。干旱条件下,豫谷1号具有更高的叶片相对含水量。干旱胁迫显著降低了两个谷子品种花期的叶绿素a、叶绿素b及总叶绿素含量,且安04降低幅度均大于豫谷1号。干旱胁迫均显著增加了豫谷1号拔节期和开花期的叶片可溶性糖含量,而安04叶片可溶性糖含量并没有发生显著性变化,同时干旱胁迫显著增加了豫谷1号β-淀粉酶基因SiBAM1的表达水平。施用β-淀粉酶活性抑制剂α-环糊精,xiaomi叶片可溶性糖及脯氨酸含量显著降低,进一步加重了干旱对xiaomi的生长抑制。综上所述,干旱胁迫诱导谷子β-淀粉酶基因表达和β-淀粉酶活性升高从而水解淀粉形成可溶性糖,高可溶性糖含量对谷子提高抗旱性起重要作用。     

棉花花铃期抗旱性综合评价及指标筛选

以90份国内棉花为材料,在大田采用花铃期胁迫,考察6个农艺性状和单株产量(Y值)指标,采用综合抗旱系数、因子分析、隶属性函数值、聚类分析、灰色关联度和广义遗传力分析相结合的方法,对其抗旱性进行综合评价、抗旱性划分和评价指标筛选。结果表明,基于D值相关性状指标对干旱胁迫关联度位次依次为:单株产量、有效铃数、有效果枝数、株高、单铃重、衣分、第一果枝节位。因子分析表明,3个公因子可代表棉花抗旱性72.45%的原始数据信息量。基于D值和加权抗旱系数(WDC值)的各品种抗旱性排序相近,位居前10位的抗旱品种基本相同。各品种D值与综合抗旱系数(CDC值)、WDC值之间均呈极显著正相关,广义遗传率分析表明D值的遗传率为55.4%,为最高,其次为CDC值、WDC值。各品种Y值与CDC、WDC值间极显著正相关;根据D值将试验材料划分为5个抗旱级别,可较好地反映品种的选育条件及适应地区。试验结果说明基于遗传力大小的综合抗旱指标中用D值为主要参数,WDC为辅助评价参数,评价以单株产量为主要考量目标的棉花抗旱性是适宜且必须的;以抗旱性综合评价方法进行棉花抗旱性综合评价、抗旱性划分和评价指标筛选是可行且有效的。     

Physiological responses of cotton to a single waterlogging at high and low N-levels

Surface-irrigated cotton (Gossypium hirsutum L.) grown on slowly draining clay soil is subjected to short-term periods of waterlogging at each irrigation which generally results in reduced productivity. The sequence of above- and below-ground plant responses to transient waterlogging and the role of N availability in modifying the immediate responses were studied. Lysimeters of Marah clay loam (a Natrustalf) were instrumented to monitor soil and plant responses to a 7-day waterlogging event beginning 67 days after sowing. Cotton (‘Deltapine 61’) plants (8 per lysimeter) were grown with two levels of added N (300 kg ha⁻¹ and 30 kg ha⁻¹) and two irrigation treatments (flooded and control). Measured soil-O₂ levels decreased rapidly upon surface flooding because water displaced air and root zone respiration consumed O₂. The rate of O₂ consumption was 2.7 times greater in the high-N treatment than the low-N treatment. This difference was associated with a 1.8 fold difference in numbers of observed roots. Root growth was only slightly affected by flooding. Leaf growth decreased by 28%, foliage temperature increased 2.3% and apparent photosynthesis decreased by 16%. It is suggested that flooding reduced photosynthetic activity within 2 days while other stress symptoms became apparent after about 6 days. Although this stress was reflected in a trend for decreased plant productivity, the effect of flooding on boll dry mass at harvest was not significant at the level of replication used. The single waterlogging did not cause yield reductions comparable to those observed elsewhere when several waterlogging events were imposed. Contribution from the CSIRO, Centre for Irrigation Research, Griffith, NSW, Australia and USDA-ARS, Morris, MI, USA, in cooperation with the univ. of Minnesota.     

A large ephemeral release of nitrogen upon wetting of dry soil and corresponding root responses in the field

To assess changes in soil nutrients, root growth and mycrorrhizal infection in response to rain events, a water pulse was applied to a very dry soil. Wetting of a dry soil in the Great Basin of the Western United States led to a striking pulse of available soil nitrate in a field plot, but available phosphate was not affected. This is the first field demonstration of this phenomenon in the Great Basin as far as we are aware. This pulse was only apparent for a few days, probably due to microbial immobilization of the nitrogen. Root ammonium uptake capacity increased within one day of the water pulse, but new root growth was not apparent until 3 days after the water pulse. Thus, to capture this ephemeral release of nitrogen, enhanced uptake capacity of existing roots was probably more important than development of new roots. Mycorrhizal infection was not affected by the water pulse treatments. However, since the water pulse only affected nitrogen availability and mycorrhizae are generally most effective in facilitating acquisition of less mobile nutrients such as phosphate, mycorrhizae likely do not play an important role in taking advantage of this opportunity provided by the pulse of water.     

花铃期土壤持续干旱对棉铃对位叶气体交换参数和叶绿素荧光特性的影响

在盆栽条件下,以杂交棉泗杂3号为材料,以花铃期正常灌水\[土壤相对含水量(SRWC)(75±5)%\]为对照,设花铃期SRWC(60±5)%和SRWC(45±5)%持续干旱50 d两个处理,研究棉铃对位叶气体交换参数和叶绿素荧光参数在持续干旱过程中的动态变化和响应机制.结果表明: SRWC (60±5)%处理0～21 d棉铃对位叶的净光合速率(P_n)、气孔导度(g_s)、胞间CO₂浓度(C_i)下降,气孔限制值(L_s)上升,叶绿素荧光参数无显著变化,P_n下降的主要原因是气孔限制;处理21～49 d棉铃对位叶P_n持续下降,C_i上升,L_s下降,同时最大光化学效率(F_v/F_m)、实际光化学效率(Φ_PSII)和光化学猝灭系数(q_P)显著降低,非光化学猝灭系数(NPQ)先升后降,P_n下降的主要原因是非气孔限制;此时叶片PSII系统受到损伤,光合机构及光合酶系统被破坏,同时成铃强度急剧下降,成铃数降低,导致产量下降.SRWC(45±5)%处理0～14 d棉铃对位叶P_n、g_s、C_i显著下降,L_s急剧上升,F_v/F_m、Φ_PSII、q_P无显著变化,P_n下降主要由气孔限制引起;处理14～49 d,棉铃对位叶P_n缓慢下降,C_i上升,L_s下降,F_v/F_m、Φ_PSII和q_P不断降低,而NPQ先升后降,表明P_n下降主要由非气孔限制引起,同时成铃强度急剧下降,成铃数减少,产量降低.本试验条件下,SRWC(60±5)%和SRWC(45±5)%处理下棉花生长的临界胁迫时间分别为21和14 d.     

Physiological and growth responses of Centaurea maculosa (Asteraceae) to root herbivory under varying levels of interspecific plant competition and soil nitrogen availability

Summary Centaurea maculosa seedlings were grown in pots to study the effects of root herbivory by Agapeta zoegana L. (Lep.: Cochylidae) and Cyphocleonus achates Fahr. (Col.: Curculionidae), grass competition and nitrogen shortage (each present or absent), using a full factorial design. The aims of the study were to analyse the impact of root herbivory on plant growth, resource allocation and physiological processes, and to test if these plant responses to herbivory were influenced by plant competition and nitrogen availability. The two root herbivores differed markedly in their impact on plant growth. While feeding by the moth A. zoegana in the root cortex had no effect on shoot and root mass, feeding by the weevil C. achates in the central vascular tissue greatly reduced shoot mass, but not root mass, leading to a reduced shoot/root ratio. The absence of significant effects of the two herbivores on root biomass, despite considerable consumption, indicates that compensatory root growth occurred. Competition with grass affected plant growth more than herbivory and nutrient status, resulting in reduced shoot and root growth, and number of leaves. Nitrogen shortage did not affect plant growth directly but greatly influenced the compensatory capacity of Centaurea maculosa to root herbivory. Under high nitrogen conditions, shoot biomass of plants infested by the weevil was reduced by 30% compared with uninfested plants. However, under poor nitrogen conditions a 63% reduction was observed compared with corresponding controls. Root herbivory was the most important stress factor affecting plant physiology. Besides a relative increase in biomass allocation to the roots, infested plants also showed a significant increase in nitrogen concentration in the roots and a concomitant reduction in leaf nitrogen concentration, reflecting a redirection of the nitrogen to the stronger sink. The level of fructans was greatly reduced in the roots after herbivore feeding. This is thought to be a consequence of their mobilisation to support compensatory root growth. A preliminary model linking the effects of these root herbivores to the physiological processes of C. maculosa is presented.     

Increased root length and branching in cotton by soil application of the plant growth regulator PGR-IV

Field and growth chamber studies were used to determine the effect of in-furrow application of PGR-IV on root and shoot development, and yield of cotton. In the field study, an in-furrow application of PGR-IV @ 73 mL ha^–1 at planting increased yield by 18% compared to the untreated control, and by 11% compared to 2-foliar applications of 292 mL/ha^–1 each at pinhead square stage of flower development and at first flower appearance. Growth chamber studies revealed that the in-furrow applications of PGR-IV @ 1.131L/plant dramatically increased root length (+47%), root dry weight (+29%), number of lateral roots per plant (+75%), and nutrient uptake one week after planting. These differences were still apparent five weeks later at pinhead square but to a lesser degree. The yield enhancement from the foliar applications was associated with increases in leaf growth, nutrient uptake, and boll number, whereas the yield enhancement from the soil application was associated with enhanced root growth and nutrient uptake. The positive effect of PGR-IV on root growth and accelerated early-season growth could have very substantial benefits in cotton production.     

不同演替状态下高寒草甸土壤物理性质与植物根系的相互关系

采用空间代时间的方法,以高寒嵩草草甸不同退化演替状态土壤物理性质(土壤机械阻力、温度、湿度)为变量,探讨高寒草甸不同退化阶段土壤物理性质同植物根系生长特质的相互关系。结果表明:高寒嵩草草甸根系分布具有明显的"V"型垂直构型特征;高寒嵩草草甸根系以细根为主,直径<0.5 mm的根系占全剖面根系总长的90.8%—93.6%。土壤紧实度和土壤湿度与植物根系直径细化具有显著的正相关关系(P<0.05);土壤温度与根系细化之间具有显著的负相关关系(P<0.05),且其对高寒嵩草草甸根系生长特性形成的贡献率最高,说明高寒嵩草草甸植物根系生长构型特征的主控因子为温度。高寒嵩草草甸根系细化及表聚现象与土壤物理性质之间具有一定程度的互馈效应。低温、高紧实度和较高的土壤湿度有助于形成高密度和细根构型的草毡表层,这种土壤根系构型也是高寒草甸植物群落为适应放牧干扰及恶劣环境的应激性改变。该发现对明晰草地退化演替过程中生态系统构件对外界干扰改变的响应和适应过程及为制定合理有效的退化高寒草甸恢复措施提了供理论依据。     

不同西瓜基因型对干旱胁迫的生理响应及其抗旱性评价

以来源于不同地区的12个西瓜基因型为试材,采用盆栽控水的方式进行持续干旱处理,研究干旱胁迫对西瓜幼苗株高、根长、鲜质量及干物质积累等生长状况的影响,比较不同基因型材料对干旱胁迫的生理响应差异,同时依据旱害指数对其抗旱性进行直接评价,并采用隶属函数法进一步验证和综合评价.结果表明: 干旱处理下,12个西瓜基因型对干旱胁迫的耐受能力存在明显差异,各基因型开始出现旱害症状的时间和发生旱害的程度各不相同.干旱胁迫降低了西瓜幼苗的株高、地上、地下鲜质量和地上干物质积累量,普遍提高了根冠比,而对根长和地下干质量存在正向和负向两种不同的影响.干旱处理后,西瓜叶片的相对含水量和叶绿素含量均不同程度降低,丙二醛、过氧化氢和超氧阴离子含量增加,脯氨酸大量积累,而可溶性蛋白含量以及抗氧化酶活性则因基因型的不同而表现出不同的结果.分析认为,3个野生型材料M20、KY-3和Y-2为抗旱性强的西瓜种质,Y34、金美人和04-1-2为敏感种质,而其余基因型为中抗种质.     

金银花容器苗对干旱胁迫下接种根际促生细菌的生理响应

在盆栽试验条件下,以金银花容器苗为试材,研究了不同干旱强度下接种蜡样芽孢杆菌(Bacillus cereus)L90对植物生理特征的影响。结果表明:随着干旱胁迫强度的增加,金银花容器苗的光合速率和气孔导度逐渐降低;而干旱环境下接种L90可显著提高气孔导度,缓解干旱胁迫对净光合速率的抑制;且干旱强度增加,缓解效果增强。接种B.cereus L90可显著抑制干旱胁迫下金银花容器苗PSⅡ最大光化学效率、实际光化学效率和光化学猝灭系数的降低,抑制非光化学猝灭系数的升高。虽然L90并没有提高对照处理中光合色素的绝对含量,但可显著抑制干旱环境下金银花叶片中光合色素的分解。干旱显著降低了金银花叶片中细胞分裂素含量,增加了脱落酸(ABA)的含量;在干旱胁迫下,接种L90可显著提高叶片中细胞分裂素的含量,并可促使根部产生的ABA运输到叶片中。干旱胁迫程度较轻时,L90对金银花容器苗的相对含水量和相对电导率影响不显著;而在重度干旱时,同对照相比,干旱及接种L90处理的相对含水量分别降低20.56%和10.21%,相对电导率分别提高31.42%和16.08%,接种L90处理的变化幅度明显较小。因此,干旱生境下接种B.cereus L90,可增加叶片中细胞分裂素含量,抑制光合色素的分解及光合能力的下降,提高金银花容器苗在干旱环境中的适应能力。