干旱胁迫下外源甜菜碱对苹果叶片光合及相关特性的影响

以2年生烟富3/M9T337苹果幼树为试材,用甜菜碱200mmol·L~(-1)叶面喷施,研究干旱胁迫下喷施甜菜碱苹果幼树PSⅡ、渗透调节及抗氧化酶的响应。结果表明,干旱胁迫下,喷施甜菜碱促使苹果幼树叶片可溶性糖和游离脯氨酸含量升高,提高苹果幼树渗透调节能力;并提高SOD、CAT、APX抗氧化酶活性,减少MDA和H_2O_2积累,缓解了干旱胁迫对细胞结构的伤害;同时提高叶片相对含水量和叶绿素含量,从而提高叶片光合能力。甜菜碱提高苹果幼树抗旱性的主要作用机制可能是其对渗透调节物质代谢的调节及对抗氧化酶等生物大分子物质结构的保护。     

外源水杨酸和脱落酸复合处理提高杜鹃花叶片耐热性

以生长一致2年生的"胭脂蜜"盆栽杜鹃花为试材,以喷施蒸馏水为对照(CK),以水杨酸(SA)、脱落酸(ABA)及SA+ABA复合处理喷施2次叶片为处理,研究了SA和ABA处理对39℃/29℃高温胁迫下叶片抗氧化和耐热性的影响,以期通过喷施SA和ABA来提高杜鹃花耐热能力。结果表明:与对照相比,经SA、ABA和SA+ABA复合处理均可提高叶片可溶性总糖、脯氨酸含量、相对含水量和叶绿素含量,降低叶片的相对电导率;促进叶片超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性增加,降低叶片H_2O_2和细胞膜脂过氧化产物丙二醛(MDA)含量。但以SA+ABA复合处理对提高杜鹃花的耐热性效果最好,ABA次之,然后是SA。因此,SA+ABA复合处理更能促进渗透物质合成,提高抗氧化能力和细胞完整性,从而提高对高温胁迫抗性。     

叶面喷施褪黑素对干旱胁迫下苹果抗旱生理生化指标的影响

为探讨褪黑素对干旱胁迫下苹果生理生化指标的影响,以盆栽山定子砧1年生"红富士"苹果为试材,用不同浓度(50、100和200 mg/kg)褪黑素分别进行叶面喷施(连续喷3次,间隔期7 d)处理(以清水为对照)后,测定了控水(干旱胁迫)下各处理叶片水势、丙二醛(MDA)、脯氨酸(Pro)含量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)等3种抗性相关酶活性的变化。结果表明,随着干旱胁迫程度(控水时间)增加,叶片水势下降,MDA含量、Pro含量、SOD活性、POD活性和CAT活性呈上升趋势,复水后则基本恢复。喷施褪黑素能缓解叶片水势的下降,能降低叶片MDA含量,能进一步提高Pro含量、SOD活性、POD活性和CAT活性,且100和200 mg/kg处理的效果好于50 mg/kg处理,但100和200 mg/kg处理之间没有明显差异。叶面喷施褪黑素可以缓解干旱对苹果幼苗的影响,提高苹果幼苗的抗旱性。综合抗旱效果和经济因素,推荐褪黑素使用浓度为100 mg/kg。     

外源SA对盐胁迫下雪里蕻幼苗生理特性的影响

研究了外源水杨酸(SA)对盐胁迫下雪里蕻幼苗叶片细胞保护酶活性、丙二醛(MDA)含量、游离脯氨酸含量的影响。研究结果表明,盐胁迫下外源SA处理可明显降低雪里蕻幼苗叶片细胞MDA含量,提高游离脯氨酸含量,增强超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性。通过对各生理效应指标的综合评定,100mg/LSA缓解雪里蕻幼苗盐害的效果较好。     

臭氧胁迫下外源脱落酸对矮牵牛的影响

臭氧作为大气中主要的污染气体之一,对植物的毒害作用已引起人们的广泛关注。脱落酸(ABA)作为一种渗透调节物质,其浓度变化可以调节和改善植物对逆境的适应能力。该试验以观赏型矮牵牛为试材,通过开顶箱(OTCs)模拟熏蒸,研究高浓度O_3(100nmol·mol-1)下叶面喷施5、30μmol·L~(-1) ABA对矮牵牛抗性生理指标的变化规律。结果表明:在臭氧胁迫下矮牵牛叶片出现失水皱缩、水渍斑块症状,随着喷施ABA浓度提高,以上症状减轻;光合色素含量显著升高,喷施ABA的处理光合色素含量与对照值接近;喷施5μmol·L~(-1)和30μmol·L~(-1) ABA处理后,较喷施蒸馏水的处理,矮牵牛叶片MDA含量显著下降27.78%~55.22%,POD活性提高11.53%~47.72%,SOD活性提高33.94%,CAT活性提高125.45%~525.00%;可溶性蛋白质含量显著下降22.95%~23.02%。以上结果说明,ABA有效缓解了臭氧对矮牵牛的伤害,但矮牵牛的伤害程度随着高浓度臭氧熏蒸时间的增加而增加,且不同的品种表现出一定的差异。     

水杨酸对镍胁迫下甜瓜幼苗生理活性的影响

试验研究水杨酸(SA)对镍(Ni)胁迫下甜瓜幼苗膜系统、光合系统和抗氧化酶系统的变化规律。结果表明:Ni胁迫下甜瓜幼苗的SOD、POD、CAT活性、游离脯氨酸含量和丙二醛含量上升,叶绿素含量下降;水杨酸处理显著提高了Ni胁迫下甜瓜幼苗抗氧化酶活性和叶绿素含量,降低了游离脯氨酸、MDA含量;水杨酸能够减轻Ni对甜瓜幼苗的伤害。     

干旱胁迫下外源物质对黄瓜幼苗的影响

用水杨酸、草酸、脯氨酸对黄瓜种子进行浸种处理以及对黄瓜幼苗进行叶面喷施处理,研究其幼苗在干旱胁迫下体内SOD、CAT、MDA、Pro、电导率以及叶片水势的变化及其与外源物质的关系,为减轻干旱对黄瓜幼苗的伤害采取措施提供理论依据.结果表明:浓度为1.0、2.0、4.0 mmol/L水杨酸浸种处理可以显著改善幼苗的生长状况,使植株低矮、粗壮,对形成黄瓜壮苗有积极的促进作用;水杨酸、草酸和脯氨酸对黄瓜种子进行浸种处理,在干旱胁迫下,水杨酸2.0 mmol/L浸种处理能提高黄瓜幼苗的耐旱性,随干旱胁迫时间的延长,黄瓜叶片电解质的渗出增加,CAT活性增强,MDA含量增加,叶片水势降低;水杨酸、草酸和脯氨酸在黄瓜幼苗四叶一心期进行叶面喷施处理,水杨酸0.1 mmol/L能显著缓解干旱胁迫对幼苗造成的伤害,草酸5 mmol/L喷施处理效果次之,以上处理均能提高黄瓜幼苗的耐旱性;水杨酸、草酸和脯氨酸叶面喷施处理具有时效性,其有效处理在3 d之内作用效果明显,提高了黄瓜幼苗的耐旱性,在喷施药剂处理的第5天,作用效果明显减弱,喷施药剂的第7天,几乎完全没有作用;水杨酸可以提高黄瓜幼苗的耐旱性,使其保护酶活性提高,增加Pro含量,减少MDA积累对膜造成的伤害.     

干旱胁迫对北美丁香生长和部分抗旱生理生化指标的影响

以2年生北美丁香"詹姆斯"为试材,用盆栽方法人工模拟土壤干旱胁迫条件,研究了其生长和部分抗旱生理生化指标对水分胁迫的响应。结果表明:丁香苗具有一定的抗旱耐旱潜力,当遭遇干旱胁迫时,其可以通过调节自身的渗透调节物质含量和保护酶活性来减轻干旱伤害。随着干旱胁迫加剧,丁香苗植株高度和茎基生长速率逐渐降低,在重度干旱胁迫下生长几乎停止;随着干旱胁迫强度的增加,其叶片叶绿素和相对含水率(RWC)含量逐渐降低;叶片相对电导率、丙二醛(MDA)和脯氨酸(Pro)含量呈现不断增多的趋势;超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性先升高后降低,在干旱胁迫40d时活性达到最高,在干旱胁迫50d后其含量不断降低。     

外源水杨酸对干旱胁迫下桔梗幼苗生理生化指标的影响

以桔梗幼苗为试材,采用20%聚乙二醇(PEG-6000)作为渗透介质人工模拟干旱胁迫,探讨了外源添加水杨酸对干旱胁迫下桔梗幼苗的抗氧化酶活性、渗透调节物质和内源激素的影响。结果表明:干旱胁迫下外源添加水杨酸提高了超氧化物歧化酶(SOD)、过氧化物酶(POD)和抗坏血酸过氧化物酶(AsA-POD)活性,提高了可溶性糖和脯氨酸含量;处理7d后,干旱胁迫下添加水杨酸后脱落酸含量升高,赤霉素含量降低。说明干旱胁迫下,外源水杨酸可通过提高抗氧化酶活性和渗透调节物质的含量提高桔梗幼苗的抗干旱胁迫能力,对植物内源激素也有一定的调控作用。     

外源物质对低温胁迫下番茄幼苗生理指标的影响

研究了外源物质ABA、SA、CaCl2对低温胁迫下番茄幼苗体内游离脯氨酸、MDA、叶绿素含量、POD活性以及电解质渗透率的影响。结果表明:3种外源物质均能有效的提高番茄幼苗的抗低温能力;均能降低番茄的相对电导率,缓解低温胁迫后叶绿素含量的下降,保持相对较高的POD活性,削弱丙二醛(MDA)积累,保持细胞膜的完整性;外源物质使番茄幼苗渗透调节物质(脯氨酸)含量极显著高于对照,提高了幼苗的抗冷性。     

Effect of brassinosteroids on drought resistance and abscisic acid concentration in tomato under water stress

The effect of brassinosteroid (BR) on relative water content (RWC), stomatal conductance (g_s), net photosynthetic rate (PN), intercellular CO₂ concentration (Ci), lipid peroxidation level, activities of antioxidant enzymes and abscisic acid concentration (ABA) in tomato (Lycopersicon esculentum) seedlings under water stress was investigated. Two tomato genotypes, Mill. cv. Ailsa Craig (AC) and its ABA-deficient mutant notabilis (not), were used. Water stress was achieved by withholding water and both the AC and not plants were treated with 1 μM 24-epibrassinolide (EBR) or distilled water as a control. The RWC, g_s, Ci and PN were significantly decreased under water stress. However, EBR treatment significantly alleviated water stress and increased the RWC and PN. EBR application also markedly increased the activities of antioxidant enzymes (catalase, ascorbate peroxidase and superoxide dismutase) while it decreased g_s, Ci and the contents of H₂O₂ and malondialdehyde (MDA). Interestingly, ABA concentration in AC and not plants was markedly elevated after EBR treatment although the increasing rate and amplitude of ABA in not plants treated by EBR was significantly lower than those in AC plants. Our study suggested that amelioration of the drought stress of tomato seedlings may be caused by EBR-induced elevation of endogenous ABA concentration and/or the activities of antioxidant enzymes.     

Induction of drought tolerance by salicylic acid in seedlings of cucumber (Cucumis sativus L.)

Summary

Salicylic acid (SA) is a common, plant-produced signal molecule that is responsible for inducing tolerance to a number of biotic and abiotic stresses. An experiment was therefore conducted to test whether the application of SA at various concentrations (0, 0.25, 0.50, 0.75, or 1.00 mM) by seed soaking, or as a foliar spray would protect cucumber (Cucumis sativus L.) seedlings subjected to drought stress. Thirty-six-day-old seedlings (n = 12 seedlings per treatment) were exposed to drought stress for 14 d. Pretreatment with SA improved the majority of the physiological (e.g., relative chlorophyll content and chlorophyll fluorescence ratio) and morphological parameters (e.g., shoot and root fresh and dry weights) measured in cucumber seedlings subjected to drought stress. SA ameliorated the injuries caused by drought stress by increasing shoot tissue proline contents and preventing an increase in leaf electrolyte leakage. SA was more effective at increasing the drought tolerance of cucumber seedlings when applied using the seed-soaking method, rather than as a foliar spray. The best drought protection appeared to be obtained when seeds were soaked in 0.50 mM SA.     

葡萄砧木的抗旱性鉴定与研究

采用盆栽方法,对16个葡萄砧木品种(系)资源进行了抗旱性鉴定,并研究了干旱胁迫下葡萄砧木的生理变化规律,探讨了葡萄砧木的抗旱性机制,初步评价了抗旱性鉴定的指标和方法。结果表明:葡萄砧木品种(系)间抗旱性存在差异,16个砧木品种(系)被划分为4个抗旱等级;随着干旱胁迫时间延长,葡萄砧木生理代谢减弱(脯氨酸、可溶性糖、叶绿素等),并且抗旱性强的砧木生理代谢水平普遍高于抗旱性弱的砧木;可以把叶片相对含水量、叶绿素、丙二醛作为鉴定抗旱性大小评价的主要指标。     

Malformation of roses due to drought stress

Rose plants were subjected to the same degree of drought stress but at different stages of development. Irrigation was suspended for a certain period according to the soil moisture deficit and the leaf stomatal resistance.Rose flower development was most sensitive to drought stress prior to petal and stamen initiation. At those stages, drought stress affected the quality of the flowers (reduction in the number of well-formed petals and in length of the flower bud). Application of drought stress during stamen initiation (or during petal initiation in winter) caused abortions and malformations of the flower bud once the stem had elongated to approximately 15 cm. Such malformed buds had no carpels, and stamens were tightly packed on the center of the receptacle.     

Effect of cold and drought stress on blueberry dehydrin accumulation

Summary

Dehydrins are a group of plant proteins which respond to any type of stress that causes dehydration at the cellular level, such as cold and drought stress. Previously, three dehydrins of 65, 60, and 14.kDa were identified as the predominant proteins present in cold acclimated blueberry (Vaccinium corymbosumLinn.) floral buds. Levels were shown to increase with cold acclimation and decrease with deacclimation and resumption of growth. In the present study, to determine if dehydrins are induced in other organs in response to low temperature treatment (48C) and in response to drought, accumulation of dehydrins was examined in leaves, stems, and roots of two cultivars and one wild selection (a V. corymbosum cultivar, a V. ashei Reade cultivar, and a V. darrowi Camp selection) of blueberry by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting. Cold treatment involved placing plants in a cold room maintained at 48C for five weeks; drought stress was imposed by withholding water from potted, greenhouse-grown plants for 34.d. Relative water content (RWC) of shoots was determined periodically throughout the drought treatment. Dehydrins accumulated with both cold and drought stress but their molecular masses varied depending upon blueberry species. Dehydrins accumulated to higher levels in stems and roots than in leaves with cold stress and to higher levels in stems than in either roots or leaves with drought stress. Furthermore, cold treatment combined with dark treatment induced higher levels of dehydrins than cold treatment combined with a 10.h light/14.h dark photoperiod, suggesting that dehydrins may be responsive to changes in photoperiod as well. In the cold-stress experiment, the level of dehydrin accumulation was correlated with expected level of plant cold hardiness in the three genotypes. In the drought stress experiment, dehydrins accumulated prior to significant changes in RWC, and dehydrin levels did not appear to be closely correlated with RWC either among or within genotypes.     

西瓜品种叶部特征与抗旱性的关系

为探讨西瓜叶片特征与抗旱性的关系,找寻能表征西瓜品种抗旱性的叶部特征,通过盆栽试验研究了9个已知抗旱性强弱的西瓜材料叶片结构、水分生理和气孔特性。结果表明:利用西瓜材料单叶面积、叶片解剖特征(栅栏组织/海绵组织、上表皮、下表皮和栅栏组织/叶片厚)和气孔特性(气孔的长/宽、气孔密度、气孔导度、气孔开口大小、单位叶面积气孔相对面积)隶属函数值判定的耐旱级别与大田直接鉴定所得的耐旱等级正相关。西瓜叶片的解剖特征和气孔特性可用于品种抗旱性鉴定,但单一指标不能准确判断西瓜品种的抗旱性。     

Multi-scale factors and long-term responses of Chihuahuan Desert grasses to drought

Factors with variation at broad (e.g., climate) and fine scales (e.g., soil texture) that influence local processes at the plant scale (e.g., competition) have often been used to infer controls on spatial patterns and temporal trends in vegetation. However, these factors can be insufficient to explain spatial and temporal variation in grass cover for arid and semiarid grasslands during an extreme drought that promotes woody plant encroachment. Transport of materials among patches may also be important to this variation. We used long-term cover data (1915–2001) combined with recently collected field data and spatial databases from a site in the northern Chihuahuan Desert to assess temporal trends in cover and the relative importance of factors at three scales (plant, patch, landscape unit) in explaining spatial variation in grass cover. We examined cover of five important grass species from two topographic positions before, during, and after the extreme drought of the 1950s. Our results show that dynamics before, during, and after the drought varied by species rather than by topographic position. Different factors were related to cover of each species in each time period. Factors at the landscape unit scale (rainfall, stocking rate) were related to grass cover in the pre- and post-drought periods whereas only the plant-scale factor of soil texture was significantly related to cover of two upland species during the drought. Patch-scale factors associated with the redistribution of water (microtopography) were important for different species in the pre- and post-drought period. Another patch-scale factor, distance from historic shrub populations, was important to the persistence of the dominant grass in uplands (Bouteloua eriopoda) through time. Our results suggest the importance of local processes during the drought, and transport processes before and after the drought with different relationships for different species. Disentangling the relative importance of factors at different spatial scales to spatial patterns and long-term trends in grass cover can provide new insights into the key processes driving these historic patterns, and can be used to improve forecasts of vegetation change in arid and semiarid areas.     

20个马铃薯品种抗旱性鉴定及评价指标筛选

中国马铃薯生产区很大一部分在降雨不均或水资源不足地区,为满足此类地区品种需求,对马铃薯开展抗旱性评价。选择20个马铃薯常规栽培品种,在块茎膨大期对其植株叶片进行生理生化指标的测定,成熟期测产,综合评价抗旱性。结果表明,干旱胁迫对马铃薯块茎产量的影响极显著,胁迫后19个品种减产均达50%以上。测定的5个生理生化指标均与抗旱系数和指数之间存在不同程度的相关性,可以作为马铃薯品种抗旱性评价的指标。根据5个指标干旱胁迫后的测定数据计算隶属函数值,结合抗旱系数和抗旱指数评价品种抗性,筛选出克新19号、克新21号、成功、克新2号和东农303为抗旱性较强的品种。     

不同柑橘砧木的耐旱性评价

【目的】快速评价柑橘砧木的耐旱性。【方法】对枳及其杂种、宽皮柑橘和香橙在内的共10种砧木苗采用人工控水处理的方法进行干旱处理。通过干旱条件下植株的形态表现和对与逆境相关的生理生化指标进行测定,综合评价各种砧木的耐旱性。【结果】在干旱处理下,不同砧木的萎焉时间和萎焉程度有明显差异。丙二醛、脯氨酸、可溶性蛋白含量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性等与抗逆性相关的生理生化指标的测定结果显示,10个砧木的SOD活性、CAT活性、POD活性都是先升后降,而脯氨酸含量、丙二醛含量、可溶性蛋白含量在不同砧木间的变化趋势存在差异。【结论】用综合隶属函数、主成分分析法对各生理指标进行综合分析能较为客观地对耐旱性进行评价,结合植株形态表现观察结果,发现在本次测试的10种柑橘砧木中,枳杂种‘ZZ-022’的耐旱性最强,而‘扁平橘’的耐旱性最弱。