不同相思树种单株抗寒性综合评价

选择赤云相思(Acacia mangium×A. auriculiformis (Chiyun))、杂交相思(A. mangium×A. auriculiformis)和马占相思(A. mangium) 3个品种的8个单株,对其扦插繁殖幼苗进行12、9、6、3、0℃的低温处理,以25℃为对照,测定幼苗叶片相对电导率、丙二醛、可溶性糖、游离脯氨酸、可溶性蛋白和超氧化物歧化酶含量等6个生理指标,应用隶属函数法综合各项生理指标进行抗寒性评价,筛选高度抗寒品种单株,为相思选育提供优质材料。结果表明:在低温胁迫下,幼苗叶片相对电导率升高,游离脯氨酸、可溶性蛋白和可溶性糖含量增加,且这4个指标可作为相思树种抗寒性评价的参考指标;结合生理指标的变化情况,相思发生寒害的温度主要是0～6℃;依据平均隶属函数值,综合筛选出抗寒性较强的品种单株依次是杂交相思1、杂交相思4和赤云相思,抗寒性最弱的是马占相思11。     

马占相思树苗对低温冻害的抗性研究

以盆栽马占相思PNG17868家系树苗为材料,研究了低温胁迫下树苗生长发育有关的生理生化指标的变化及其抗冻害的关系。结果表明:随着低温胁迫程度的加深和时间延长,植株细胞电导率显著升高,细胞膜ATPase活性呈下降趋势,而可溶性糖、脯氨酸和可溶性蛋白质含量亦不断升高,表现出耐寒植物较典型的生理特点,说明该植物有明显的渗透调节能力和抗寒性。在零下低温(0～6℃)胁迫下,植物细胞防御系统的保护酶类(CAT、POD、SOD)的活性先是升高,然后有所下降,但下降幅度不大。这表明了马占相思PNG17868家系对低温有较强的适应能力,在温度日益降低(0～6℃)条件下体内保护酶仍能维持较高的活性水平,减轻了由膜脂过氧化引起的膜伤害,是植物提高抗寒性、免遭低温冻害的重要原因。     

几种保护酶活性变化与马占相思树对低温胁迫的抵抗性的关系研究

马占相思(Acacia mangium)QLD19835家系树苗在人工气候室经低温处理后,体内相关的生理指标及酶活性产生明显变化。随着温度不断下降至-6℃产生的冻害导致植株细胞膜ATP酶活性有所下降,而蛋白质的含量则显著升高,同时,细胞保护酶SOD、POD、CAT的活性呈下降趋势,但仍能维持较高的活性水平。这些实验结果表明,马占相思QLD19835对低温胁迫能产生一种防卫反应,从而对冻害有一定适应性,而具有一定活性的细胞保护酶及蛋白质的含量提高可能是植株有较强抗寒力的重要原因。     

脯氨酸和可溶性糖在南极冰藻低温适应机制中的作用

对低温胁迫下两种南极冰藻胞内的脯氨酸和可溶性糖含量的变化进行分析研究,探讨两种冰藻对低温的适应性机制。测定不同培养温度和培养时间下两种南极绿藻细胞中的脯氨酸和可溶性糖含量,获得其在低温下随温度和胁迫时间变化的趋势,分析其产生变化的原因。结果显示,温度越低,塔胞藻Pyramidomonas sp.L-1胞内的脯氨酸和可溶性糖含量增加越明显。-5℃,培养48 h后,脯氨酸含量是初始值的6.5倍,可溶性糖含量增加60%。衣藻Chlamydomonas sp.L-4胞内脯氨酸的含量同样为温度越低,胞内脯氨酸的含量越高;但随时间变化趋势与塔胞藻Pyramidomonas sp.L-1相反,含量随温度作用时间的增加出现减少的趋势。-5℃,48 h后脯氨酸含量基本维持不变,可溶性糖含量增幅达90%。结果表明,脯氨酸和可溶性糖在南极冰藻的低温适应性机制中具有重要的作用,但在不同藻种中的作用机制不同。     

盐胁迫对低温预处理石榴种子萌发及幼苗生理生化的影响

以催芽‘峄城大青皮甜’石榴种子为材料,经2~4℃低温预处理5、10和15d,置于不同盐分梯度下进行种子萌发试验,并测定分析幼苗生长、细胞保护酶活性、可溶性糖和脯氨酸含量及电导率变化,以阐明盐胁迫下低温预处理对石榴种子萌发和幼苗生长及生理生化的影响。结果显示:(1)适当的低温预处理和低盐胁迫能提高石榴种子的发芽率和发芽势,低温处理5d和0.1%低盐环境下有利于壮苗生长。(2)适当时间的低温预处理(5d)可显著提高石榴幼苗的保护酶(SOD、POD、CAT)活性,长时间的低温预处理(15d)却降低了幼苗的保护酶活性;随着盐浓度的升高石榴幼苗的保护酶活性也逐渐升高,并在盐浓度为0.3%时均达到最大值,说明当盐浓度高于0.3%时超出了石榴幼苗保护酶系统的调节范围,从而发生盐害。(3)低温预处理5d和10d降低了幼苗可溶性蛋白和脯氨酸的含量;随着盐浓度的升高幼苗可溶性蛋白和脯氨酸的含量也逐渐升高。(4)5d和10d的低温预处理可以提高石榴幼苗细胞膜透性,随着盐浓度的升高相对电导率也显著升高。研究表明,在低盐环境下,适当时间的低温预处理能显著促进石榴种子萌发生长,其幼苗能通过调整自身渗透调节物质可溶性蛋白和脯氨酸含量以及体内保护酶活性,降低细胞膜脂过氧化程度,保证细胞膜的完整性,维持正常的细胞代谢活性,从而有效减轻盐胁迫对植株的伤害,表现出较强的抗盐性。     

5-氨基乙酰丙酸对辣椒植株低温胁迫伤害的缓解效应

以‘超越五号'辣椒品种为试材,研究了低温胁迫期间及随后的常温恢复过程中5-氨基乙酰丙酸(ALA 25 mg·L-1)处理对始花期辣椒植株生长量,叶片中脯氨酸、可溶性糖、可溶性蛋白含量,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性和电解质渗透率及丙二醛(MDA)含量的影响,以探讨ALA提高辣椒抗寒性的生理机制.结果表明,低温胁迫下叶面喷施25 mg·L-1的ALA可显著提高辣椒植株生长量,增加叶片中脯氨酸、可溶性糖及可溶性蛋白含量,增强其POD、CAT及APX活性,并显著降低辣椒叶片中SOD活性、电解质渗透率和MDA含量.叶面喷施ALA也显著降低了恢复过程中辣椒叶片中的渗透调节物质含量和抗氧化酶活性,使膜伤害基本恢复到对照水平.可见,外源ALA处理可通过提高低温胁迫下辣椒叶片的渗透调节能力和抗氧化能力,促进植株生长,缓解低温胁迫对植株的伤害.     

乙烯利处理下罂粟有机渗透调节物质的变化

本研究采用随机区组设计探明不同浓度乙烯利处理与罂粟渗透调节物质的关系.在罂粟苗期对植株喷施不同浓度的乙烯利,并测定其叶片中渗透调节物质可溶性糖、可溶性蛋白和脯氨酸相对含量的变化.测定分析结果表明:随着处理浓度的升高和时间的延长,可溶性糖含量和脯氨酸含量呈增长趋势.≥8 000 mg/L浓度处理的可溶性糖含量极显著地高于CK;≥4 000 mg/L浓度处理的脯氨酸含量极显著地高于CK;浓度为16 000 mg/L的处理对可溶性蛋白含量影响极显著地高于其余各处理,≤2 000 mg/L浓度处理与CK相比差异不显著.因此研究显示,低浓度乙烯利处理能使罂粟相对适应胁迫,但高浓度乙烯利处理会影响罂粟的生长发育.一定程度上为利用乙烯利防除毒品原植物罂粟提供了理论依据.     

低温弱光下辣椒3种渗透调节物质含量变化及其与品种耐性的关系

以12个耐低温弱光的辣椒品种为试验材料,模拟日光温室低温弱光逆境,研究了辣椒叶片中脯氨酸(Pro)、可溶性搪、可溶性蛋白含量的变化及其与耐低温弱光性之间的相关性.结果表明,15℃/5℃(昼/夜)、100μmol·m-2·s-1光照处理使辣椒叶片的Pro含量、可溶性糖含量升高,可溶性蛋白含量于处理前期升高,后期浇档?低温弱光处理10 d的可溶性蛋白含量和处理20 d的可溶性糖含量与辣椒耐低温弱光性呈显著正相关;10个品种的Pro含量与品种的耐低温弱光性呈极显著正相关,Pro的累积表现为保护作用;耐低温弱光性较强的品种'湘研1号'和较弱的品种'湘研16号'中Pro含量与耐性呈负相关,Pro的累积表现为伤害性反应.     

盐胁迫对小麦代换系渗透调节物质的影响及染色体效应

以中国春-Synthetic 6x小麦染色体代换系及其亲本为材料,设置对照(0 mmol/L Na Cl)和盐胁迫(150 mmol/L Na Cl)2个处理,通过测定不同盐处理条件下代换系幼苗渗透调节物质Na+、K+、可溶性糖、可溶性蛋白及脯氨酸含量变化,探讨盐胁迫对小麦代换系幼苗渗透调节物质的影响,并对其调控相关特性的基因进行染色体定位。结果表明,在盐胁迫条件下,小麦代换系的无机渗透调节物质Na+、K+含量明显升高,有机渗透调节物质可溶性糖、可溶性蛋白及脯氨酸含量显著增加。对相关性状的染色体定位分析表明,Synthetic 6x的1A、2A、3B、7B、1D、4D和7D染色体上存在抑制Na+含量升高的基因,4A、7A染色体上可能存在使K+含量升高的基因;6A、7A和7D染色体上可能存在使可溶性糖含量升高的基因,1A、2A、4A和6A染色体上可能存在使可溶性蛋白含量升高的基因,7A、6D染色体上可能存在使脯氨酸含量升高的基因。即Synthetic 6x的第4、7染色体(4A、4D;7A、7D)上可能含有调控无机调节物质的基因,第6染色体上(6A、6D)可能含有调控有机渗透调节物质的基因。     

低温胁迫下菠萝幼苗生长与生理特性变化

以国内外10个菠萝品种幼苗为材料,研究了它们在低温胁迫下的生长及其渗透调节物质、细胞膜透性的变化特征,并综合评价它们的耐寒性.结果表明:(1) 随低温处理时间的延续,各品种幼苗单株干重虽然均呈逐渐增加趋势,但不同品种生物量增加幅度存在显著差异.(2) 随着低温处理时间的延长,各品种叶片脯氨酸含量和细胞膜相对透性逐渐升高;可溶性蛋白含量总体上初期升高后期降低,而‘巴厘'、‘珍珠'、‘台农17号'、‘台农19号'和‘MD-2'的可溶性蛋白在处理末期又有所上升;可溶性糖含量变化趋势复杂.(3) 低温胁迫处理9 d后,各菠萝品种叶片中的脯氨酸和可溶性蛋白含量及细胞膜相对透性均增加;可溶性糖含量除‘珍珠'略有减少外,其余均增加.(4)经过各指标赋分分级综合评价后认为,‘MD-2'和‘巴厘'品种耐寒性最强;‘台农17号'、‘台农16号'、‘巴厘突变体'、‘台农13号'、‘台农19号'和‘无刺卡因'耐寒性中等;‘珍珠'和‘台农6号'耐寒性最弱.研究发现,菠萝耐寒性强弱可根据干物质积累结合其它生理指标来综合评判.     

马占相思花粉离体萌发研究

马占相思(Acacia mangium)是含羞草科(Mimosaceae)金合欢属(Acacia Mill.)树种,在我国的广东、广西、福建以及海南等省(区)大面积种植推广。马占相思用途广泛,其杂交育种工作近年来逐渐受到重视,马占相思花粉研究对其杂交育种成败具有重要影响。该研究以新鲜的马占相思花粉为供试材料,开展不同蔗糖浓度(50、100、150、200、250和300 g·L~(-1))、不同硼酸浓度(100、200和300 mg·L~(-1))以及不同培养温度(26、28和30℃)对马占相思花粉离体萌发影响的研究,同时使用筛选出的马占相思花粉离体萌发的最佳处理,开展对另外3株与初试的马占相思生长发育状况接近的马占相思的花粉活力检测研究,并观察记录马占相思花粉离体萌发特征。结果表明:将刚开放的马占相思花序采回室内阴干,于次日10:00后,用毛笔刷法成功收集大量马占相思花粉,经显微镜观察检测,花粉纯度较高,可以保证后续研究备用;马占相思花粉离体萌发的最佳处理为200 g·L~(-1)蔗糖、100 mg·L~(-1)硼酸、28℃培养温度;马占相思花粉在培养24 h之后,花粉萌发率最高(为94.28%),花粉管最长(为6.0 D);检测3株马占相思的花粉萌发率分别为90.11%、82.31%、85.67%,具有显著差异。该研究结果为今后进一步开展人工控制授粉、选育优良的相思杂交新品种提供了基础。     

Effects of Low Temperature on Winter Wheat and Cabbage Leaves

Contents of soluble proteins, proline and chlorophyll in winter wheat (Triticum aestivum cv. Doğu-88) and cabbage leaves (Brassica oleracea convar. acephala) during acclimation to low temperature were investigated. When both of the plants species were cold acclimated, soluble proteins, proline and chlorophyll contents were higher than in the controls (non-acclimated). Also protein patterns differed between the plants at control and cold conditions. This revised version was published online in July 2006 with corrections to the Cover Date.     

Counteraction of Salinity Stress on Wheat Plants by Grain Soaking in Ascorbic Acid, Thiamin or Sodium Salicylate

The interactive effects of salinity stress (40, 80, 120 and 160 mM NaCl) and ascorbic acid (0.6 mM), thiamin (0.3 mM) or sodium salicylate (0.6 mM) were studied in wheat (Triticum aestivum L.). The contents of cellulose, lignin of either shoots or roots, pectin of root and soluble sugars of shoots were lowered with the rise of NaCl concentration. On the other hand, the contents of hemicellulose and soluble sugars of roots, starch and soluble proteins of shoots, proline of either shoots or roots, and amino acids of roots were raised. Also, increasing NaCl concentration in the culture media increased Na⁺ and Ca²⁺ accumulation and gradually lowered K⁺ and Mg²⁺ concentration in different organs of wheat plant. Grain soaking in ascorbic acid, thiamin or sodium salicylate could counteract the adverse effects of NaCl salinity on the seedlings of wheat plant by suppression of salt stress induced accumulation of proline.     

Enhanced salt tolerance of tomatoes by exogenous salicylic acid applied through rooting medium

In Tunisia, like in the other countries of the Mediterranean, tomato is ranked among the important vegetables in the economic sphere. Tunisia ranks as the first consumer of this vegetable in the world. However, tomatoes are exposed to multiple environmental stresses. In particular, salinity is the most stressful limiting factor to productivity. Salt tolerance of the tomato is susceptible to be ameliorated by genetic and physiologic ways. Salicylic acid (SA), a plant phenolic, is now considered as a hormone-like endogenous regulator, and its role in the defense mechanisms against biotic and abiotic stressors has been well documented. So, the aim of this study was to investigate the impact of exogenous application of SA (0.01 mM) on growth, nutritional behavior, and some metabolic parameters (total chlorophyll, soluble sugars, proline, and proteins) of tomato plants cv. Moneymaker exposed to NaCl (100 mM). Our results showed that the application of 0.01 mM SA to tomato plants via root drenching attenuate the depressive effect of salinity on plants. This amelioration results in stimulation of growth and development of plant. Under stress conditions, SA-treated plants exhibited more accumulation of photosynthetic pigments and K(+) contents. Thus, SA induces an increase in soluble sugars in roots and leaves; also, we noted the increase of proteins only in roots. Overall, the adverse effects of salt stress tomato plants were alleviated by the exogenous application of SA at vegetative stage, which upregulated nutrition and the accumulation of some organic solutes and osmoprotectors such sugars, proline, and proteins. So salicylic acid can be greatly used to enhance salt tolerance of tomato plants.     

Influence of arbuscular mycorrhiza on organic solutes in maize leaves under salt stress

A pot experiment was conducted to examine the effect of the arbuscular mycorrhizal (AM) fungus, Glomus mosseae, on plant biomass and organic solute accumulation in maize leaves. Maize plants were grown in sand and soil mixture with three NaCl levels (0, 0.5, and 1.0 g kg⁻¹ dry substrate) for 55 days, after 15 days of establishment under non-saline conditions. At all salinity levels, mycorrhizal plants had higher biomass and higher accumulation of organic solutes in leaves, which were dominated by soluble sugars, reducing sugars, soluble protein, and organic acids in both mycorrhizal and non-mycorrhizal plants. The relative abundance of free amino acids and proline in total organic solutes was lower in mycorrhizal than in non-mycorrhizal plants, while that of reducing sugars was higher. In addition, the AM symbiosis raised the concentrations of soluble sugars, reducing sugars, soluble protein, total organic acids, oxalic acid, fumaric acid, acetic acid, malic acid, and citric acid and decreased the concentrations of total free amino acids, proline, formic acid, and succinic acid in maize leaves. In mycorrhizal plants, the dominant organic acid was oxalic acid, while in non-mycorrhizal plants, the dominant organic acid was succinic acid. All the results presented here indicate that the accumulation of organic solutes in leaves is a specific physiological response of maize plants to the AM symbiosis, which could mitigate the negative impact of soil salinity on plant productivity.     

Changes in the water status and osmotic solute contents in response to drought and salicylic acid treatments in four different cultivars of wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis>)

Salicylic acid (SA) controls growth and stress responses in plants. It also induces drought tolerance in plants. In this paper, four wheat (Triticum aestivum L.) cultivars with different drought responses were treated with SA in three levels of drain (90, 60, 30% of maximum field capacity) to examine its interactive effects on drought responses and contents of osmotic solutes that may be involved in growth and osmotic adjustment. Under drought condition, the cultivars Geza 164 and Sakha 69 had the plant biomass and leaf relative water content (LRWC) greater than the cultivars Gemaza 1 and Gemaza 3. In all cultivars, drought stress decreased the biomass, LRWC, and the contents of inorganic solutes (Ca, K, Mg) and largely increased the contents of organic solutes (soluble sugars and proline). By contrast, SA increased the biomass, LRWC and the inorganic and organic solute contents, except proline. Correlation analysis revealed that the LRWC correlated positively with the inorganic solute contents but negatively with proline in all cultivars. SA caused maximum accumulations of soluble sugars in roots under drought. These results indicated that SA-enhanced tolerance might involve solute accumulations but independently of proline biosynthesis. Drought-sensitive cultivars had a trait lowering Ca and K levels especially in shoots. Possible functions of the ions and different traits of cultivars were discussed.     

南美斑潜蝇为害对黄瓜体内主要营养物质、 次生代谢物质及叶绿素含量的影响

南美斑潜蝇Liriomyza huidobrensis (Blanchard)是一种危害多种蔬菜和观赏植物的多食性害虫。本研究采用蒽酮比色法、 考马斯亮蓝法、 磷钼酸 磷钨酸比色法、 索氏回流法及丙酮法, 分别测定了南美斑潜蝇1~3龄幼虫不同为害程度（系统受害、 轻度受害和重度受害）对黄瓜叶片内可溶性糖、 可溶性蛋白质、 单宁、 黄酮及叶绿素含量的影响。结果表明： 南美斑潜蝇幼虫为害后, 黄瓜叶片中可溶性糖、 可溶性蛋白质和叶绿素的含量随着为害程度的增强而显著降低（P<0.01）, 最大降幅分别为62%, 35%和40%; 单宁和黄酮的含量随着为害程度的增强而显著上升（P<0.01）, 最高升幅分别为26%和53%; 并且具有系统性影响。结果提示, 南美斑潜蝇幼虫为害导致寄主植物营养物质含量下降、 光合作用降低, 而次生代谢物质含量上升, 从而对植食者产生诱导抗性。本研究结果为进一步揭示南美斑潜蝇与其寄主植物相互作用关系及其机理提供了有益的参考。