Effect of Alkali Stress on Soluble Sugar, Antioxidant Enzymes and Yield of Oat

Alkali stress can cause severe crop damage and reduce production. However, physiological processes involved in alkali stress in oat seedlings are not well understood. In this study, physiological responses and yield of oat to alkali stress were studied using the alkali-tolerant oat genotype Vao-9 and the alkali-sensitive oat genotype Baiyan 5. The results were： （i） low concentrations of alkali stress （25 and 50 mmol L^-1） significantly reduced the yield and grain weight while increased the oat grain number per spike. A negative correlation between yield and malondialdehyde （MDA） content at the jointing and grain filling stages and positive correlations between yield on one hand and superoxide dismutase （SOD）, and peroxidase （POD） activities on the other at the jointing stage were observed. There was a positive correlation between MDA and soluble sugar at the grain filling stage; （ii） soluble sugar content was increased at the jointing and grain filling stages and decreased at the heading stage by alkali stress; （iii） alkali stress increased the SOD activity during the heading and grain filling stages, and increased the POD activity at the heading stage. As compared to the control, the increase of MDA contents in alkali-treated oat was observed, during the jointing, heading and grain filling stages; （iv） under alkali stress, the oat genotype Vao-9 showed higher antioxidant enzyme activity and lower soluble sugar contents during the heading stage, and lower MDA contents than those in the oat genotype Baiyan 5 under alkali stress. The result suggested that the high ROS scavenging capacity and soluble sugar levels might play roles in oat response to alkali stress,

Comprehensive evaluation of tolerance to alkali stress by 17 genotypes of apple rootstocks

Alkaline soils have a great inlfuence on apple production in Northern China. Therefore, comprehensive evaluations of toler-ance to such stress are important when selecting the most suitable apple rootstocks. We used hydroponics culturing to test 17 genotypes of apple rootstocks after treatment with 1：1Na2CO3and NaHCO3. When compared with the normaly grown controls, stressed plants produced fewer new leaves, and had shorter roots and shoots and lower fresh and dry weights after 15 d of exposure to alkaline conditions. Their root/shoot ratios were also reduced, indicating that the roots had been severely damaged. For al stressed rootstocks, electrolyte leakage （EL） and the concentration of malondialdehyde （MDA） increased while levels of chlorophyl decreased. Changes in root activity （up or down）, as wel as the activities of peroxidase （POD）, superoxide dismutase （SOD）, and catalase （CAT） were rootstock-dependent, possibly relfecting their differences in alkali tolerance. Using alkali injury index （AI）, adversity resistance coefifcients （ARC）,cluster analysis, and evaluation of their physiological responses, we classiifed these 17 genotypes into three groups： （1） high tolerance： Hubeihaitang, Wushanbianyehaitang, Laoshanhaitang Ls2, Xiaojinbianyehaitang, and Fupingqiuzi; （2） moderate tolerance： Pingyitiancha, Laoshanhaitang Ls3, Hubeihaitang A1, Deqinhaitang, Balenghaitang, Maoshandingzi, Shandingzi, and Xinjiangyepingguo; or （3） low tolerance： Pingdinghaitang, Hongsanyehaitang, Xiaojinhaitang, and Sanyehaitang. These results wil signiifcantly contribute to the selection of the most suitable materials for rootstocks with desired levels of tolerance to alkali stress.

Osmotic Regulation of Betaine Content in Leymus chinensis Under Saline-alkali Stress and Cloning and Expression of Betaine Aldehyde Dehydrogenase(BADH) Gene

The potted Leymus chinensis seedlings were treated with saline-alkali solution of six different（from Ⅰ to Ⅵ） concentrations. The results demonstrate that the betaine content and Betaine-aldehyde dehydrogenase（BADH： EC 1.2.1.8） activities have a direct relation with increased stressing time in the same treatment; both exhibit a single peak with increasing the concentration of saline-alkali solution, and number V shows the highest value. The BADH gene of Leyrnus chinensis was cloned by RT-PCR and RACE technology and was designated as LcBADH. The cDNA sequence of LcBADH was 1774bp including the open reading frame（ORF） of 1521bp（coding 506 amino acids）. The vector of prokaryotic expression was constructed by inserting the LcBADH gene fragmcnt into pET30a（＋） and transformed into E. coli BL21（DE3）. The result of SDS-PAGE shows that the idio-protein with a molecular mass of 56.78 kDa was effectively expressed in the recombinant bacteria induced by isopropyl fl-D-thiogalactoside（IPTG）.

Effect of Saline-alkali Stress on Seed Germination and Seedling Growth of Oat

Neutral black soil was mixed with strong saline-alkali soil in different weight ratios, then physiological indexes during seed germination and seedling growth in soil of different ratios and the corresponding leaching liquor treatments were observed to explore effect of saline-alkali stress on oat seed germination and seedling growth, and analyze tolerance of oat to saline-alkali soil. The results showed that germination ability of oat seeds reduced with the increasing saline-alkali stress, salt injury index increased and seedling growth was inhibited. Effect of different saline-alkali stresses on germination ability of oat seeds showed difference, and effect of leaching liquor treatment on oat seed germination was stronger than that of soil treatment.

Effects of salt-alkali stress on active oxygen metabolism in roots of Spiraea × bumalda 'Gold Mound' and Spiraea × bumalda 'Gold Flame'

Under artificially-simulated complex salt-alkali stress, the levels of active oxygen metabolism in roots were studied using three-year-old cutting seedlings of Spiraea × bumalda ‘Gold Mound＇ and Spiraea × bumalda ‘Gold Flame＇. The present study aimed at exploring the antioxidant capacity in roots of spiraeas and revealing their adaptability to salt-alkali stress. Results indicate that the oxygen free radicals contents, electrolyte leakage rates and MDA contents in roots of Spiraea × bumalda ＇Gold Mound＇ and Spiraea × bumalda ＇Gold Flame＇ show an increasing tendency with the increases of the salinity and pH value, whereas the activities of superoxide dismutase （SOD）, peroxidase （POD） and catalase （CAT） all increased firstly and then decreased. With the increase in intensity of salt-alkali stress, the CAT activity in roots of Spiraea × bumalda ‘Gold Flame＇ is higher and the increasing extents in the oxygen free radicals contents, electrolyte leakage rates as well as MDA contents are lower compared with Spiraea × bumalda ‘Gold Mound＇, indicating that Spiraea × bumalda ‘Gold Flame＇ has a stronger antioxidant capacity.

Transcriptome analysis reveals the effects of alkali stress on root system architecture and endogenous hormones in apple rootstocks

Soil alkalinity is a major factor that restricts the growth of apple roots.To analyze the response of apple roots to alkali stress, the root structure and endogenous hormones of two apple rootstocks, Malus prunifolia (alkali-tolerant) and Malus hupehensis (alkali-sensitive), were compared. To understand alkali tolerance of M. prunifolia at the molecular level, transcriptome analysis was performed. When plants were cultured in alkaline conditions for 15 d, the root growth of M. hupehensis with weak alkali tolerance decreased significantly. Analysis of endogenous hormone levels showed that the concentrations of indole-3-acetic acid (IAA) and zeatin riboside (ZR) in M. hupehensis under alkali stress were lower than those in the control. However, the trend for IAA and ZR in M. prunifolia was the opposite. The concentration of abscisic acid (ABA) in the roots of the two apple rootstocks under alkali stress increased, but the concentration of ABA in the roots of M. prunifolia was higher than that in M. hupehensis. The expression of IAA-related genes ARF5, GH3.6, SAUR36, and SAUR32 and the Cytokinin (CTK)-related gene IPT5 in M. prunifolia was higher than those in the control, but the expression of these genes in M. hupehensis was lower than those in the control. The expression of ABA-related genes CIPK1 and AHK1 increased in the two apple rootstocks under alkali stress, but the expression of CIPK1 and AHK1 in M. prunifolia was higher than in M. hupehensis. These results demonstrated that under alkali stress, the increase of IAA, ZR, and ABA in roots and the increase of the expression of related genes promoted the growth of roots and improved the alkali tolerance of apple rootstocks.

Effects of salt and alkali stress on Reaumuria soongorica germination

Seed germination and early seedling growth are crucial stages for plant establishment. Two neutral(Na Cl and Na2SO4) and two alkali(Na HCO3 and Na2CO3) salts were selected to investigate their effects on germination and recovery responses in Reaumuria soongorica. Results show that both salt types significantly reduced germination and radicle elongation. The rate of germination and emergence of R. soongorica seeds continuously decreased as salinity increased, and the time to achieve maximum germination rate was delayed. The speed of seed germination dropped rapidly as salt concentration increased.Alkaline salts restricted the germination rate of R. soongorica seeds, and stresses resulting from alkaline salts and high concentrations of neutral salts resulted in many deformed seedlings. The length of the radicle and germ decreased with increasing salt concentration, but certain concentrations of salt and increased p H promoted germ growth. The results of regression analysis show that salt concentration was the dominant factor inhibiting R. soongorica seed germination rate. Salinity, buffering capacity, and p H all affected embryo growth, but salinity had the most pronounced effect. Seed viability under highly saline conditions appears to be a better indicator of adaptation to saline environments than seed germination under saline conditions.

Effect of Acid and Alkali Stress on Seed Germination and Seedling Growth of Caragana versicolor

With seeds of Caragana versicolor in Purang County, Tibet as the materials, the seed germination and seedling growth of C. versicolor were measured under acid and alkali stress, and the soil acidity and alkalinity for normal growth and development of C. versicolor were determined, so as to provide the theoretical basis for cultivation of C. versicolor in acidified or alkaline soil. The results showed that the seed germination of C. versicolor was promoted when treated by strong acid (pH 3) and strong alkali (pH 11) solutions, and the seedling effect was good. The results also indicated that C. versicolor was a kind of plant with strong acid and alkali resistance, suitable for cultivation in acid and alkali soil areas.

Photoresponse Process and Model Comparison of Paeonia ludlowii under Saline-alkali Stress

The research aimed to analyze changes in photosynthetic characteristics of Paeonia ludlowii under saline-alkali stress, and annual seedlings of P. ludlowii were taken as the materials. Photoresponse process of P. ludlowii leaves under saline-alkali stress was simulated, and different models were used to fit photoresponse curve. The results showed that P n of P. ludlowii leaves showed the trend of first rising and then declining with PAR increased under saline-alkali stress;both G s and T r showed a rising trend with PAR increased;C i showed the trend of first declining and then rising with PAR increased. Photoresponse curve fitted by modified rectangular hyperbolic model had the best effect, and it was the optimal fitting model. P. ludlowii could adapt to saline-alkali stress in lower concentration, showing that P. ludlowii could be introduced and cultivated in saline-alkali land at a lower level.

Ca^(2+)-dependent TaCCD1 cooperates with TaSAUR215 to enhance plasma membrane H^(+)-ATPase activity and alkali stress tolerance by inhibiting PP2C-mediated dephosphorylation of TaHA2 in wheat

Alkali stress is a major constraint for crop production in many regions of saline-alkali land.However,little is known about the mechanisms through which wheat responds to alkali stress.In this study,we identified a calcium ion-binding protein from wheat,TaCCD1,which is critical for regulating the plasma membrane(PM)H^(+)-ATPase-mediated alkali stress response.PM H+-ATPase activity is closely related to alkali tolerance in the wheat variety Shanrong 4(SR4).We found that two D-clade type 2C protein phosphatases,TaPP2C.D1 and TaPP2C.D8(TaPP2C.D1/8),negatively modulate alkali stress tolerance by dephosphorylating the penultimate threonine residue(Thr926)of TaHA2 and thereby inhibiting PM H+-ATPase activity.Alkali stress induces the expression of TaCCD1 in SR4,and TaCCD1 interacts with TaSAUR215,an early auxin-responsive protein.These responses are both dependent on calcium signaling triggered by alkali stress.TaCCD1 enhances the inhibitory effect of TaSAUR215 on TaPP2C.D1/8 activity,thereby promoting the activity of the PM H^(+)-ATPase TaHA2 and alkali stress tolerance in wheat.Functional and genetic analyses verified the effects of these genes in response to alkali stress,indicating that TaPP2C.D1/8 function downstream of TaSAUR215 and TaCCD1.Collectively,this study uncovers a new signaling pathway that regulates wheat responses to alkali stress,in which Ca^(2+)-dependent TaCCD1 cooperates with TaSAUR215 to enhance PM H+-ATPase activity and alkali stress tolerance by inhibiting TaPP2C.D1/8-mediated dephosphorylation of PM H+-ATPase TaHA2 in wheat.

Genome-wide analysis of soybean DnaJA-family genes and functional characterization of GmDnaJA6 responses to saline and alkaline stress

Plant Dna JA proteins act as molecular chaperones in response to environmental stressors.The purpose of this study was to characterize the function and regulatory mechanisms of Dna JA genes in soybean.Gene expression profiles in various soybean tissues at various stages of development indicated that Gm Dna JAs function in the coordination of stress and plant hormone responses.Gm Dna JA6 was identified as a candidate regulator of saline and alkaline stress resistance and Gm Dna JA6 overexpression lines showed increased soybean saline and alkaline tolerance.Dna J interacted with Hsp70,and Gm Hsp70 increased the saline and alkaline tolerance of plants with chimeric soybean hairy roots.

Adaptive strategy of Nitraria sibirica to transient salt,alkali and osmotic stresses via the alteration of Na+/K+fluxes around root tips

Nitraria sibirica Pall.is an important shrub with a strong salt-alkali tolerance,but the mechanism underlying this tolerance remains obscure.In this study,N.sibirica,with salt-sensitive Vigna radiata(Linn.)Wilczek as the control,was subjected to transient salt stress(100 mM NaCl),alkali stress(50 mM Na_(2)CO_(3)),and osmotic stress(175 mM mannitol).The ionic fluxes of Na^(+)and K^(+)in the root apical region were measured.Results show that,under salt and alkali stress,N.sibirica roots exhibited higher capacities to limit Na+influx and reduce K+efflux,thereby resulting in lower Na^(+)/K^(+)ratios compared with V.radiata roots.Alkali stress induced stronger Na^(+)influx and K+efflux in the root salt stress treatment;Na^(+)influx was mainly observed in the root cap,while K^(+)efflux was mainly observed in the elongation zone.While under osmotic stress,N.sibirica roots showed stronger Na+efflux and weaker K+efflux than V.radiata roots.Na+efflux was mainly observed in the root elongation zone,while K+efflux was in the root cap.These results reveal the ionic strategy of N.sibirica in response to transient salt,alkali,and osmotic stresses through the regulation of Na+/K+flux homeostasis.

Comparative Transcriptome Profiling of Glycine soja Roots Under Salinity and Alkalinity Stresses Using RNA-seq

Saline-alkaline stress can dramatically inhibit plant growth and limit crop production. Wild soybean （Glycine soja） is a crop that adapts well to such environmental stresses. In this study, RNA-sequencing technology was used to analyze the transcriptome profles of G. soja roots subjected to 50 mmol·L^-1 NaHCO3 and 150 mmol·L^-1 NaCl treatments. Totally, 2 125 differentially-expressed genes （DEGs） after NaCl treatment and 1 839 DEGs after NaHCO3 treatment were identifed. The top 14 DEGs revealed by RNA-seq were analyzed using qRT-PCR （quantitative real-time polymerase chain reaction）. Gene ontology （GO） annotation showed that most of DEGs under salt and alkali stresses were enriched in ＂metabolic process＂, ＂catalytic activity＂ and ＂binding＂ terms. To search for transcription factors （TFs） among DEGs, the data were screened against TF database PlantTFDB, and it was found that fve TF families, Apetala2/ethylene-responsive element binding proteins （AP2-EREBP）, V-myb avian myeloblastosis viral oncogene homolog （MYB）, WRKYGQK and Zinc fnger motif （WRKY）, NAM, ATAF1/2, CUC1/2 （NAC） and Cys2/His2 （C2H2） were involved in salt stress response. Other fve TF families, NAC, WRKY, MYB, AP2-EREBP and bZIP were involved in response to alkali stress. These two stress treatments shared NAC, WRKY, AP2-EREBP and MYB, and the only two different TFs were bZIP and C2H2. Forty-eight MYB TFs were differentially expressed under salt and alkali stresses, and most of them were up-regulated. This study provided useful information for further investigation of DEGs and TFs in response to saline and alkaline stresses and helped in understanding the molecular basis of the response of G. soja to saline and alkaline stresses.

紫薇响应盐胁迫和碱胁迫的代谢组分析

为探究‘红叶’紫薇(Lagerstroemia indica ‘Pink Velour’)对盐胁迫和碱胁迫的代谢响应机制,对‘红叶’紫薇1年生无性扦插苗分别进行盐胁迫(NaCl,pH=7.02)和碱胁迫(NaHCO_(3)和Na_(2)CO_(3)的Na^(+)摩尔比为2:1,pH=9.52)处理,采用液相色谱质谱(LC-MS)分析叶片代谢组学变化,并比较2个处理组与对照(CK)之间的代谢差异。结果表明:与CK相比,盐处理组共筛选出156个差异代谢物,碱处理组共筛选出176个差异代谢物,2个对比组共有23个差异代谢物,其余均为特有差异代谢物。KEGG富集分析表明,次生代谢产物生物合成、氨基酸代谢、糖类代谢、脂肪酸代谢和植物激素合成是响应盐胁迫和碱胁迫的主要代谢通路;甘氨酸、丝氨酸和苏氨酸合成代谢、ABC转运蛋白和维生素B_(6)合成代谢是盐胁迫组的特有代谢通路;缬氨酸、亮氨酸、异亮氨酸、精氨酸和脯氨酸生物合成代谢、叶酸合成代谢,以及戊糖和葡萄糖醛酸相互转化和抗坏血酸合成代谢是碱胁迫组的特有代谢通路。这些差异代谢物变化和代谢通路富集可能是紫薇响应盐胁迫和碱胁迫的主要机制。

辣椒EIL基因家族的鉴定及其在盐碱胁迫下的表达分析

EIL(Ethylene-insensitive 3-like)基因在参与植物乙烯信号通路的转导和生长发育过程中发挥着重要作用。为了解辣椒EIL基因家族成员信息,利用生物信息学手段对辣椒EIL基因家族成员的理化性质、蛋白质结构、系统进化、基因结构、保守域、启动子顺式作用元件及CaEILs基因在不同组织部位和不同非生物胁迫条件下的表达模式进行分析。同时使用实时荧光定量PCR(qRT-PCR)对辣椒叶片中CaEILs在盐碱胁迫下的表达模式进行研究。结果表明,辣椒9个CaEILs分布在6条染色体上,氨基酸数目、蛋白质理论分子质量和脂肪系数分别介于209~677、23.77~76.07 ku和63.10~87.75,且主要为酸性、亲水的不稳定性核蛋白。系统进化分析显示,CaEILs被分成了4个亚家组,9个CaEILs在根、茎、叶、花蕾、花中具有不同程度的表达,而低温、高温、高盐、干旱胁迫下均能诱导CaEILs的表达,其对以上非生物胁迫均具有不同程度的响应。此外,利用qRT-PCR对盐碱胁迫下辣椒叶片中CaEILs进行了检测,结果发现,随着处理时间的延长,CaEIL1、CaEIL2、CaEIL4、CaEIL5、CaEIL8的表达量整体呈上升趋势,而CaEIL3、CaEIL6、CaEIL7、CaEIL9的表达量整体呈下降趋势。

盐碱胁迫对水稻生长特性及产量的影响

为了有效利用并改良盐碱地及改善生态环境,以8份水稻种质资源为材料,设置轻度盐碱胁迫、中度盐碱胁迫、重度盐碱胁迫进行田间耐盐碱性分析,对植株存活率、株高、分蘖、叶绿素相对含量、每穗粒数、结实率以及千粒重等指标进行了比较,分析不同程度盐碱胁迫对水稻生长发育特性及产量的影响。结果表明,水稻品种间耐盐碱特性存在差异,水稻存活率表现为轻度盐碱胁迫>中度盐碱胁迫>重度盐碱胁迫,水稻品种从返青期至成熟期植株存活率呈下降趋势。盐碱胁迫导致水稻株高变矮、穗长变短,随着盐碱胁迫程度增加株高和穗长受到的抑制作用变强,同一品种株高和穗长数值表现为轻度盐碱胁迫>中度盐碱胁迫>重度盐碱胁迫,且3种盐碱胁迫处理间差异显著(P<0.05)。齐穗期SPAD值范围为42.5~55.6,各处理与对照间差异不显著。重度盐碱胁迫下水稻产量抑制率高达81.0%~93.7%,中度盐碱胁迫下产量抑制率为10.4%~81.3%,轻度盐碱胁迫下为5.6%~77.9%,产量及产量构成因素相对抑制率主要表现为重度盐碱胁迫>中度盐碱胁迫>轻度盐碱胁迫,盐碱化程度越高对水稻产量及产量构成因素造成的损失也越大。相关分析表明,产量相对抑制率与单位面积穗数相对抑制率极显著相关,与实粒数相对抑制率和结实率相对抑制率正相关。说明,盐碱胁迫抑制水稻生长发育,导致产量降低,但合理开发和利用中度、轻度盐碱化土地可以扩大水稻种植面积。

海洋贝类对盐度胁迫适应机制的研究进展

盐度是影响海洋贝类存活、生长、发育、繁殖等生命活动的关键因素,其生命活动时刻受到海洋局部环境中盐度变化的影响。对海洋贝类适应盐度胁迫机制的研究是学术界长期关注的问题。大量研究表明,盐度胁迫会对海洋贝类的生长、渗透调节、能量代谢和免疫反应等生物学过程产生影响。近年来,随着基因组、转录组等组学技术的发展和广泛应用,许多研究从分子水平来探讨海洋贝类适应盐度胁迫的机制。本文综述了海洋贝类在盐度胁迫过程中的调控机制,包括渗透调节、能量代谢、免疫反应,以及转录组和基因组在海洋贝类盐度胁迫机制研究中的应用,提出了广盐性海洋贝类在盐碱水领域中的开发潜力,为海洋贝类抗逆品种选育以及绿色养殖提供重要参考。

286份甘蓝型油菜种质苗期耐盐碱性综合评价

对286份甘蓝型油菜品系进行苗期耐盐碱性鉴定,通过水培试验,测定盐碱胁迫处理下叶片数、绿叶数、绿叶比、株高、根长、根重等指标,通过盐碱胁迫综合评价值(D值)、极端材料筛选分析、相关性、主成分、隶属函数、频数分析和逐步回归分析法,对不同基因型的油菜种质建立苗期耐盐碱性综合评价模型并筛选出适宜的评价鉴定指标。盐碱胁迫下,叶片数与株高呈负相关,两者的相关系数未达到显著性,其他性状之间均呈正相关并达到了显著或极显著水平。利用主成分分析法将7个耐盐碱指标综合为4个主成分,可代表油菜耐盐碱性88.349%的原始数据信息量。依据4个主成分的相对重要性(权重)进行加权,得到不同基因型的耐盐碱性综合评价值(D值)。结合隶属函数分析和极端材料筛选分析,筛选出4份耐碱盐的甘蓝型油菜种质和4份盐碱敏感种质。逐步回归分析结果表明,在油菜苗期测定其绿叶数、绿叶比、地上重、根长和根重,通过回归方程估算其D值,可以初步判断甘蓝型油菜种质资源耐盐碱性。

外源γ-氨基丁酸缓解燕麦幼苗盐碱胁迫的生理效应

为探究外源γ-氨基丁酸(GABA)对燕麦耐盐碱性的影响,以燕麦白燕2号为试验材料,在混合盐碱(NaCl∶Na_(2)SO_(4)∶NaHCO_(3)∶Na_(2)CO_(3)摩尔比为1∶9∶9∶1)胁迫下叶面喷施不同浓度GABA,测定燕麦幼苗叶绿素含量、荧光参数、渗透调节物质及抗氧化酶活性的变化,同时对幼苗生长缓解效应进行综合评价。结果表明,外源喷施4~6 mmol·L^(-1) GABA可显著提高盐碱胁迫下燕麦幼苗的叶绿素含量和光系统Ⅱ反应活性,促进光合作用;在盐碱胁迫下,与喷施清水相比,燕麦幼苗叶面喷施不同浓度GABA后,脯氨酸(Pro)、丙二醛(MDA)和可溶性糖(SS)含量分别下降了14.7%~29.7%、28.2%~54.4%和1.8%~11.8%,超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性分别提高了17.9%~58.3%、4.4%~33.4%和8.3%~19.1%。经隶属函数法综合评价得出,叶面喷施GABA提高燕麦幼苗耐盐碱性的最佳浓度为6 mmol·L^(-1)。以上结果说明,叶面喷施适宜浓度的GABA能够提高燕麦幼苗光合能力和抗氧化酶活性,降低渗透调节物质含量,提高燕麦幼苗的抗盐碱能力,有效缓解盐碱胁迫对幼苗生长带来的伤害。

盐碱胁迫对‘赤霞珠’葡萄幼苗生长及相关生理指标的影响

【目的】了解不同盐分配比和不同浓度梯度复合盐碱胁迫对‘赤霞珠’葡萄(Vitis vinfera‘Cabernet Sauvignon’)幼苗生长和抗逆生理指标的影响,确认其耐盐碱性范围及耐盐碱能力。【方法】以1年生‘赤霞珠’自根苗为试材,用NaCl、Na_(2)SO_(4)、NaHCO_(3)、Na_(2)CO_(3)按不同比例混合配制中性盐、弱碱性盐、强碱性盐3组复合盐溶液,每组各设置50,100,150 mmol/L 3个浓度梯度,以不做处理的溶液作为对照,于幼苗生长期间进行定期浇灌处理,通过室内盆栽试验模拟不同类型、不同程度盐碱胁迫,在处理后不同时期测定幼苗生长形态、生理及光合指标。【结果】(1)‘赤霞珠’幼苗茎粗和叶面积随盐碱胁迫浓度增大呈现先增大后减小的趋势,而株高基本呈现下降趋势。幼苗株高在强碱性盐组150 mmol/L胁迫处理10 d和40 d时都较同期中性、弱碱性组相应浓度显著降低。(2)随着盐碱浓度的增大,‘赤霞珠’幼苗叶片的SOD活性及MDA含量呈先增大后减小的趋势,而POD活性呈现缓慢增加的趋势;强碱性盐组叶片POD活性在胁迫处理30~50 d时均高于相应浓度的中性、弱碱性盐组,但到处理60 d后逐渐低于相应浓度其他两处理组,并以150 mmol/L浓度表现得更明显。(3)‘赤霞珠’幼苗叶片胞间CO_(2)浓度、净光合速率、蒸腾速率随着盐碱浓度的增加主要呈下降趋势,其胞间CO_(2)浓度和净光合速率均为50 mmol/L浓度处理时较高;在同期相同盐碱浓度处理下,叶片净光合速率在强碱性盐150 mmol/L胁迫处理75 d时显著低于中性、弱碱性处理组。【结论】‘赤霞珠’幼苗株高、叶面积、胞间CO_(2)浓度、净光合速率、蒸腾速率在50 mmol/L浓度处理下均呈现较好的增长趋势,而其株高及茎粗在150 mmol/L强碱性盐胁迫处理下增长不明显;一定范围内低浓度(50 mmol/L)盐碱胁迫有利于‘赤霞珠’葡萄幼苗生长。