南瓜发芽期对Na2CO3胁迫的生理响应及耐受性评价

研究了南瓜发芽期对Na2CO3胁迫的生理响应及耐受性评价。结果显示,在不同Na2CO3胁迫下,南瓜的发芽率、幼苗鲜重、主根长、侧根数和下胚轴长与对照相比均有显著差异,但下胚轴粗度变化不显著。随Na2CO3胁迫程度的加大,3个南瓜品种的相对电导率、可溶性糖含量和SOD活性呈上升趋势,丙二醛含量和根系活力则呈先升后降趋势。对11个指标进行的主成分分析显示,下胚轴长、侧根数、下胚轴粗度、发芽率、丙二醛含量和可溶性糖含量,6项指标在评价南瓜Na2CO3耐性方面比较重要。     

缺铁胁迫柑橘砧木幼苗的光合特性和叶绿体超微结构

【目的】通过研究枳壳与枳橙砧木在缺铁和正常铁浓度处理下的反应,重点揭示两种柑橘砧木光合特性、叶绿体超微结构等对铁敏感性的差异。【方法】以柑橘的枳壳砧木和枳橙砧木实生苗为试验材料,设置缺铁 (–Fe,0 μmol/L) 和正常铁 (+Fe,37.3 μmol/L) 2个处理进行营养液培养,测定了缺铁胁迫对两种砧木苗期铁元素含量与积累量、光合色素含量、叶片糖含量的影响,并进行了叶绿体超微结构的电镜扫描。【结果】缺铁胁迫显著降低了两种砧木铁元素含量与积累量、叶片光合色素含量,且枳橙砧木光合色素含量下降幅度较大。与对照相比,缺铁后枳壳砧木叶片的糖类物质含量降低,且达到显著差异水平;而枳橙砧木叶片可溶性糖、蔗糖含量显著升高,淀粉和果糖含量显著下降。另外,缺铁胁迫条件下,两种柑橘砧木片层结构模糊,嗜饿体数目增加。并且,缺铁后枳壳砧木叶绿体长度、厚度比对照分别降低了22.1%、26.4%,枳橙砧木则分别下降了55.1%、40.4%。【结论】缺铁胁迫下,枳橙砧木幼苗的铁元素含量和积累量、叶片光合色素含量、叶绿体超微结构等均比枳壳砧木受到较大影响,表明枳橙砧木比枳壳砧木对铁营养缺乏更加敏感。     

燕麦对盐碱胁迫的生理响应

通过分析渗透调节物质脯氨酸和可溶性糖含量的变化,利用洗叶技术分析燕麦叶片洗脱物的离子组成,以及对气孔周围结晶的X—ray分析,并利用扫描电子显微镜观察燕麦叶片的表面结构,研究了燕麦对盐碱胁迫的生理响应。结果表明,在盐碱胁迫下,燕麦叶片中脯氨酸和可溶性糖含量增加;经过混合盐处理后,叶片洗脱物主要由Clˉ、Na^＋、K^＋、HCO3ˉ、Mg^2＋和Ca^2＋等离子组成,不含CO3^2-和SO4^2-,其中Clˉ、Na^＋、K^＋含量极显著高于对照,HCO3ˉ、Mg^2＋含量显著高于对照,Ca^2＋含量与对照差异不显著;通过扫描电镜观察叶片表面,发现气孔周围分布着盐结晶,表明燕麦通过气孔排盐适应盐碱胁迫。     

荞麦对酸铝胁迫生理响应的研究

铝毒害是限制酸性土壤中植物生长的重要因素,以荞麦(FagopyrumesculentumMoench.)为实验材料,在沙培条件下,用不同浓度(0,10,100,1000mg/L)、不同pH(3,4,5)的铝溶液处理,在出苗后的第14d和28d测试与铝胁迫有直接关系的5个生理指标。结果表明,溶液的铝浓度和pH的变化对荞麦生理都有明显的影响,最低浓度的铝处理10mg/L在不同pH下已经影响了荞麦的正常生长,和对照相比根系活力(RA)下降、根质膜透性(MP)增大、叶片内丙二醛(MDA)和游离脯氨酸(Pro)的含量以及过氧化物酶(POD)的活性升高,并且随着铝处理浓度的升高,荞麦体内各生理指标和对照差异性加大;同一铝浓度下pH5和pH3相比,MP降低、RA增强、叶片内MDA和Pro的含量以及POD的活性有所下降。铝胁迫下荞麦体内各生理指标的变化有显著的相关性。随着荞麦的生长,铝毒害有所缓解。     

紫苏对不同浓度镉胁迫的生理响应

为探讨紫苏的耐镉生理机制, 通过水培试验, 研究了镉离子浓度为0 mg·L^-1(对照)、2.0 mg·L^-1、5.0 mg·L^-1、10.0 mg·L^-1 条件下紫苏的生长、镉富集作用及叶片的保护酶活性。结果表明, 2.0 mg·L^-1、5.0 mg·L^-1、10.0 mg·L^-1 镉胁迫下, 紫苏单株生物量比对照分别减少28.4%、42.4%、66.0%, 不同处理间均存在极显著差异;3 个镉离浓度下紫苏的镉富集量依次为462.4 μg·株^-1、705.0 μg·株^-1、609.7 μg·株^-1, 富集系数依次为91.9、70.0、51.1, 具备镉超积累能力。此外, SOD、POD、CAT 酶活测定结果显示, 随镉离子浓度升高, 紫苏叶片的SOD 活性和MDA 含量显著升高, POD 和CAT 活性显著下降, 破坏了体内保护酶系统的平衡, 抑制紫苏生长。     

NaCl胁迫下温室内两个砧木的生理响应机制

为了探明NaCl胁迫下不同砧木耐盐性差异的生理机制,采用水培,研究了温室栽培条件下2个耐盐性不同的砧木(黑籽南瓜和超丰8848瓠瓜)在盐胁迫下的生长量、根系活力、离子含量和酶活性的变化.结果表明,盐胁迫下,2个砧木的地上部和根干质量、根系活力、Ca2 和Mg2 的含量及K /Na 比值均显著降低,叶片中Na 的含量虽然显著增加,但叶中Na 的含量显著低于根茎;超丰8848瓠瓜的SOD、POD活性、MDA含量均无显著变化,而黑籽南瓜的SOD、POD活性显著增强,MDA含量显著增加.低盐胁迫下Na 主要集中在根茎部,高盐胁迫下Na 主要集中在茎部.通过根茎阻止Na 向叶片运输,是2个砧木耐盐的主要生理机制.超丰8848瓠瓜较黑籽南瓜耐盐性强的生理机制在于其在盐胁迫下具有更高的根系活力.     

不同桃自根砧对干旱胁迫的生理响应及抗逆机理研究

砧木的抗旱能力直接影响桃品种生长发育,选择适宜抗旱性桃砧木对桃产业发展有积极的促进作用。为阐明不同桃砧木对干旱胁迫生理响应机制,以5种桃砧木扦插苗为试材,通过盆栽控水方式,研究不同程度干旱胁迫下5种桃自根砧的叶片水分特性、渗透调节物质、抗氧化物酶及叶绿素含量变化。结果表明,随着干旱程度加重,5种砧木相对含水量、临界含水量下降,自然饱和亏、临界饱和亏及需水程度上升,组织密度和自由水含量逐渐减少,束缚水含量则增大,持水能力、组织水势和耐旱系数下降。各干旱胁迫处理的丙二醛(MDA)含量、 游离脯氨酸(Pro)含量、可溶性糖含量和叶绿素含量均增加;过氧化物酶(POD)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性提高,其中随干旱程度加重,丙二醛(MDA)含量、游离脯氨酸(Pro)含量均呈增加趋势,SOD活性、CAT活性也均呈提升趋势,可溶性糖含量、叶绿素含量、POD活性变化不尽相同。综合隶属函数分析可知,桃自根砧品种间抗旱性由强到弱依次为樱桃李5号、RA、樱桃李3号、GF677、樱桃李1号。     

木麻黄种子萌发对铬胁迫的生理生态响应研究

试验研究不同浓度CrCl3 胁迫对木麻黄种子萌发初期一些生理生态特征的影响结果表明 ,随CrCl3 处理浓度的加大而木麻黄种子萌发率逐渐降低 ,幼苗株高、根长、鲜物质量和干物质量均逐渐降低 ;脯氨酸、超氧负离子含量先升后降 ,蛋白质含量逐渐升高 ;超氧化物歧化酶活性 (SOD)先升后降 ,过氧化物酶活性 (POD)和过氧化氢酶活性 (CAT)则逐渐增加 ,SOD、POD、CAT活性可作为毒物的敏感指示者。环境胁迫条件下植物体形态特征的响应常滞后于生理特征。     

二倍体与三倍体香蕉苗对冷胁迫的生理响应

通过对二倍体野生蕉与三倍体威廉斯香蕉苗进行24h的7℃低温处理,测量其组织含水量(WC)、脯氨酸(Pro)含量、丙二醛(MDA)含量、总抗氧化能力的变化,同时测定其气体交换特征参数与叶绿素荧光参数,比较分析其变化特征。结果显示:低温处理下,威廉斯香蕉WC较其对照处理显著性下降,下降幅度为14.36%;低温与对照处理的野生蕉WC与对照处理的威廉斯香蕉WC保持相同水平。低温下威廉斯香蕉Pro含量(与干重比)较其对照显著下降,下降幅度为17.05%,而野生蕉Pro变化不显著。低温处理下的威廉斯香蕉MDA含量显著高于其他处理,而其总抗氧化能力也较其他处理显著下降。光系统Ⅱ最大光化学效率(Fv/Fm)以低温处理的威廉斯香蕉下降幅度最大,与其他处理相比达显著性差异。光强光合曲线中随光强的增加,低温处理的威廉斯香蕉净光合速率(Pn)增加幅度低于对照处理,低温与对照处理的野生蕉随光强增加其Pn保持相同幅度的增加,且增加幅度居于对照与低温处理的威廉斯香蕉之间。总之,三倍体威廉斯香蕉对冷害更为敏感,其膜系统氧化加剧、脯氨酸含量降低、失水量增加,总抗氧化能力降低,光系统Ⅱ最大光化学效率明显受抑制、净光合速率明显下降;然而,同样低温处理下二倍体野生蕉则表现出与对照相似的生理状态,因此可认为野生蕉作为具抗寒性种质可作为抗寒育种的重要材料。     

荆芥幼苗对盐胁迫的生理响应

为探究盐胁迫对荆芥幼苗生理特性的影响,采用盆栽砂培试验,研究不同浓度盐胁迫(0、25、50、75和100 mmol·L^-1 NaCl)下荆芥幼苗生长、质膜稳定性、渗透调节、抗氧化酶系统、离子吸收和分配的变化。结果表明,随着盐浓度的增加,荆芥盐害指数逐渐升高,幼苗株高增加速率和比叶面积均逐渐降低,单株干重和叶绿素含量均呈先增加后减少的趋势,且均在25 mmol·L^-1 NaCl处理下达到最大;叶片中丙二醛(MDA)含量和电解质渗漏率均显著增加;可溶性蛋白和脯氨酸含量均呈先增加后减少趋势,且分别在50和75 mmol·L^-1 NaCl处理下达到最大,而可溶性糖含量则不断上升;超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性均呈先上升后下降的趋势,在25 mmol·L^-1 NaCl处理下达到最大,而过氧化物酶(POD)活性则持续下降。盐胁迫下,荆芥的根、茎、叶大量积累Na^+,但主要集中在地上部分,同时各部位K^+、Ca²⁺含量及K^+/Na^+、Ca²⁺/Na^+值均显著下降。综上,荆芥幼苗对盐胁迫极为敏感,但对低浓度的盐胁迫(25 mmol·L^-1 NaCl)具有一定的耐受性。本研究结果为荆芥的规范化栽培和抗逆驯化研究奠定了理论基础。     

Differential tolerance of bush bean cultivars to excess manganese in solution and sand culture

Nineteen bush bean cultivars were screened for tolerance to excess Mn in nutrient solution and sand culture experiments. Seven‐day‐old seedlings were treated with full strength Hoagland No. 2 nutrient solution containing different Mn concentrations for 12 days in the greenhouse.

Cultivars showing the greatest sensitivity to Mn toxicity were ‘Wonder Crop 1’ and ‘Wonder Crop 2'; those showing the greatest tolerance were ‘Green Lord’, ‘Red Kidney’ and ‘Edogawa Black Seeded’.

Leaf Mn concentration of plants grown in sand culture was higher than that for plants grown in solution culture. The lowest leaf Mn concentration at which Mn toxicity symptoms developed, was higher in tolerant than in sensitive cultivars. The Fe/Mn ratio in the leaves at which Mn toxicity symptoms developed, was higher in the sensitive cultivars than in the tolerant ones.

We concluded that Mn tolerance in certain bush bean cultivars is due to a greater ability to tolerate a high level of Mn accumulation in the leaves.     

Effect of manganese on concentrations of Zn,K, Ca and Mg in two bush bean cultivars grown in solution culture

Two bush bean cultivars [Phaseolus vulgaris L. cv. ‘Wonder Crop 2’ (WC‐2) and ‘Green Lord’ (GL)], differing in Mn toxicity, were grown in a growth chamber for 12 days in Hoagland No. 2 nutrient solution containing 0.05 to 1 ppm Mn as MnCl₂4H₂O with 1 ppm Fe as Fe‐EDTA, at an initial pH 5.00. Concentrations of Zn, K, Ca and Mg in the tissues of two bush bean cultivars were examined in relation to Mn toxicity.

The concentration of Zn in the leaves of Mn‐sensitive WC‐2 increased significantly with increasing Mn concentration in the solution, but such levels were not toxic to the plants.

The percent distribution of Zn and K in Mn‐sensitive WC‐2 plants (% of total uptake) significantly increased in the tops and decreased in the roots with increasing Mn concentration in the nutrient solution; however, Mn treatment had no effect on distribution of either Ca or Mg in WC‐2. External Mn concentration had little or no effect on the K, Ca, or Mg concentration in the tops of Mn‐tolerant GL.     

Tolerance of limpograss (PI 364344) to excess manganese in acid soil and nutrient solution

Previous studies showed that limpograss, Hemarthria altissima (Poir), Stapf & C. E. Hubb (PI 364344) was tolerant to low temperature and to high concentrations of Al in acid soil, mine spoil and nutrient solution. Additional experiments were conducted to test the tolerance of this limpograss clone to excess Mn, another potential growth‐limiting factor in acid soils.

Cuttings from a single plant were grown in pots of Mn‐toxic Zanesville soil with no lime (pH 5.1) and 1250 ppm CaCO (pH 6.3) and in nutrient solutions containing 0, 4, 8, 16, 32 or 64 ppm Mn at pH 4.0. The grass was highly tolerant to excess Mn in both media. Liming the soil from pH 5.1 to 6.3 did not significantly affect top dry weight of the first harvest and significantly decreased that of the second. In nutrient solutions at pH 4.0 top dry weights were not significantly affected by Mn concentrations up to 64 ppm. Root dry weights were significantly increased by Mn additions of 16, 32 and 64 ppm. Limpograss (PI 364344) was not injured when Mn concentrations were as high as 930 and 9152 ppm in tops and roots, respectively. High Mn tolerance is yet another trait that should enhance the potential use of this grass in revegetating acid mine spoils and other acid sites.     

Physiology of manganese toxicity and tolerance in Vigna unguiculata (L.) Walp.

In cowpea (Vigna unguiculata (L.) Walp.) tolerance of manganese (Mn) excess depends on genotype, silicon (Si) nutrition, form of nitrogen (N) supply, and leaf age. The physiological mechanisms for improved Mn leaf-tissue tolerance are still poorly understood. On the basis of the density of brown spots per unit of leaf area and the callose content which are sensitive indicators of Mn toxicity, it was confirmed that cultivar (cv.) TVu 1987 was more Mn-tolerant than cv. TVu 91, young leaves were more Mn-tolerant, Si improved Mn tolerance, and NO₃^—-grown plants were more Mn-tolerant than NH₄⁺-grown plants. A close positive relationship existed between the bulk-leaf Mn content and the vacuolar Mn concentration from the same leaves. Since no clear and consistent differences existed between leaf tissues differing in Mn tolerance, the results suggest that accumulation of Mn in the vacuoles and its complexation by organic anions do not play a role in Mn leaf-tissue tolerance in cowpea. A near linear relationship was found between leaf Mn contents and concentrations of free (H₂O-soluble) and exchangeable-bound (BaCl₂-extractable) Mn in the apoplastic washing fluid (AWF) extracted from whole leaves by an infiltration and centrifugation technique. There were no differences in apoplastic Mn concentrations owing to genotype and form of nitrogen nutrition. However, Si decreased the Mn concentration in the AWF. With increasing bulk-leaf Mn contents, concentrations of organic anions in the AWF also increased. The results suggest that complexation of Mn by organic anions in the leaf apoplast contribute to Mn tolerance due to genotype and more clearly due to NO₃-N nutrition. Cell wall-bound peroxidase activity increased with leaf age and was higher in the Mn-sensitive cv. TVu 91 than in cv. TVu 1987. This was in agreement with a higher H₂O₂ production rate in cv. TVu 91. Also, a lower ratio of reduced to oxidized ascorbic acid in the AWF revealed that in Mn-sensitive leaf tissue, the apoplastic reduction capacity was lower than in Mn-tolerant leaf tissue when genotypes and leaves of different age were compared. We interpret our results as strong circumstantial evidence that Mn tolerance depends on the control of the free Mn²⁺concentration and of Mn²⁺-mediated oxidation/reduction reactions in the leaf apoplast.     

Foliar composition of citrus seedlings irrigated with saline waters

Abstract

The effects of increasing levels of NaCl in the irrigation water on the foliar content of N, P, K, Ca, Mg, Fe, and Mn of six citrus seedling varieties were studied. The experiment was carried out under greenhouse conditions in a factorial design. Treatments consisted of addition of irrigation waters containing 1.5, 10, 20, and 40 me NaCl/l. Increasing salinity significantly decreased K and Mn contents and increased those of N and Mg. Leaf content of P, Ca, and Fe was not affected. Results also showed that seedling variety and sampling data had a significant effect on the mineral composition of the leaf.     

Effects of excess soil manganese on stomatal function in two soybean cultivars

Manganese tolerant ‘Lee’ and Mn sensitive ‘Forrest’ soybean cultivars were grown in a potting soil with no known Mn toxicity and in Loring soil treated with excess Mn. Manganese toxicity in Loring soil was induced by the addition of Mn at 0, 100, 200 and 400 ug g^‐1 as MnSO₄.H₂O. A preliminary experiment was conducted to determine the appropriate Mn stress levels for Lee and Forrest soybean cultivars in Loring soil. Because the Loring soil produced severe Mn toxicity in both cultivars, even with an intial pH of 4.9 and no added Mn, CaCO₃ (2 g kg^‐1 ) was added to Increase the pH to 6–6.3. Soil was analysed for extractable and water soluble Mn and plants for Mn, Ca and Fe.

A second experiment was conducted to determine the effect of Mn toxicity on stomatal function. The procedure was the same as in the first experiment except that the CaCO₃ treatment was 2.5 g kg^‐1 to raise soil pH to 6.2 ‐6.5. Plants were grown in a greenhouse for 10 days and then moved to a growth chamber before making stomatal conductance measurements. A steady state porometer (LI 1600) was used. Results indicated that Mn toxicity closed stomates and decreased transpiration rates. This effect was more pronounced in Mn sensitive Forrest than in Mn tolerant Lee.     

Tolerance of rice cultivars to iron toxicity

Iron toxicity is an important growth‐limiting factor for flooded rice production in various parts of the world, including Brazil. Data related to the reaction of rice cultivars to iron concentrations are limited, especially for large numbers of cultivars. Forty rice cultivars were grown in a greenhouse in nutrient solutions containing 0.09, 0.89, and 1.78 mM Fe (5, 50 and 100 ppm Fe). The effects of excess iron were measured on plant height, root length, and root and shoot dry weight. Root and shoot dry weight were found to be more sensitive to excess iron concentration. Based on dry matter yield, reduction of shoots at higher Fe concentrations compared to the optimum or control treatment, rice cultivars were classified as tolerant, moderately tolerant, moderately susceptible or susceptible.

The effect of Fe concentrations on concentrations and contents of other nutrient was also investigated. Higher concentration of Fe in the nutrient solution exerted an inhibiting effect on the concentrations and contents of almost all macro and micronutrients.     

硼利用效率不同的柑橘砧木光合性能差异研究

【目的】 通过研究枳橙砧木 (硼不敏感型) 和枳壳砧木 (硼敏感型) 对不同硼浓度处理的反应,重点揭示两种柑橘砧木硼利用效率、光合性能及产物的差异。 【方法】 采用营养液培养的方法,设置 B0 (B0)、2 (B2)、5 (B5)、10 (B10) 和 50 μmol/L (B50) 5 个硼浓度对枳橙和枳壳砧木进行培养,通过测定植株硼含量,叶片中不同形态硼、色素含量,光合速率及糖类物质含量,探讨不同砧木硼利用效率及光合性能的差异。 【结果】 在相同硼浓度条件下,枳橙砧木植株的硼利用效率均大于枳壳砧木,不施硼时,枳橙的硼利用效率较枳壳砧木高 38.6%;两种砧木半束缚态硼/自由态硼的比值 (R) ,在各个硼处理中,枳壳砧木的 R 值均低于枳橙砧木,即枳橙砧木在细胞水平上的硼利用能力大于枳壳砧木;缺硼会降低枳壳和枳橙砧木叶绿素 a (Chl a)、叶绿素 b (Chl b) 和类胡萝卜素 (Car) 等光合色素的含量,其中枳壳砧木受缺硼影响较大,且不施硼显著降低了这两种砧木的净光合速率,相同硼水平条件下,枳橙砧木的净光合速率显著高于枳壳砧木 (B10 除外) ;两种砧木叶片可溶性糖、果糖和淀粉含量在 B0 时均高于其他处理,B0、B2 及 B5 处理,枳壳砧木叶片可溶性糖、蔗糖、果糖均显著高于枳橙砧木。 【结论】 枳橙砧木在植株水平和细胞水平的硼效率均高于枳壳砧木,光合特性和光合产物积累的不同或许是两者硼效率差异的一个关键因子。      

Tolerance of seven tropical pasture grasses to excess manganese

Abstract

Setaria and paspalum were found to be very tolerant of excess Mn. Green panic and sorghum were somewhat less tolerant with foliar symptoms due to excess Mn being exhibited in plants containing 1000 ppm Mn and yield reductions occurring in plants containing Mn concentrations of the order of 2000 ppm. Excess Mn did not effect the early seedling growth of sabi grass but regrowth was severely depressed. Rhodes grass and buffel grass were severely effected by excess manganese. Regrowth of these two species was more adversely effected than initial seedling growth indicating that these species probably would not survive to maintain a stable pasture in Mn toxic situations.

Accumulation of excess Mn was accompanied by a linear decline in Ca concentrations in all species.