Leaf stable carbon isotope composition in Picea schrenkiana var. tianschanica in relation to leaf physiological and morphological characteristics along an altitudinal gradient

To understand the effects of leaf physiological and morphological characteristics on δ13C of alpine trees, we examined leaf δ13C value, LA, SD, LNC, LPC, LKC, Chla+b, LDMC, LMA and Narea in one-year-old needles of Picea schrenkiana var. tianschanica at ten points along an altitudinal gradient from 1420 m to 2300 m a.s.l. on the northern slopes of the Tianshan Mountains in northwest China. Our results indicated that all the leaf traits differed significantly among sampling sites along the altitudinal gradient(P<0.001). LA, SD, LPC, LKC increased linearly with increasing elevation, whereas leaf δ13C, LNC, Chla+b, LDMC, LMA and Narea varied non-linearly with changes in altitude. Stepwise multiple regression analyses showed that four controlled physiological and morphological characteristics influenced the variation of δ13C. Among these four controlled factors, LKC was the most profound physiological factor that affected δ13C values, LA was the secondary morphological factor, SD was the third morphological factor, LNC was the last physiological factor. This suggested that leaf δ13C was directly controlled by physiological and morphological adjustments with changing environmental conditions due to the elevation.

The Effects of Low Phosphorus Stress on Morphological and Physiological Characteristics of Maize (Zea mays L.) Landraces

A field trial was conducted to investigate main morphological and physiological changes of different maize landraces to low-P stress at the stage of seedling. P-deficiency significantly decreased root volume, total leaf area, and plant dry weight, but greatly increased density of root hairs and root top ratio. In addition, P-deficiency induced the significant enhancement of phosphorus utilization efficiency and the amount of proline, malondialdehye （MDA）, acid phosphatase （APase）, peroxidase （POD） and superoxide dismutase （SOD）, but the significant reduction of P uptake and soluable protein content. Since P-deficiency had smaller effects on the P-tolerant maize landraces DP-44, DP-32 and DP-33 as compared with P-sensitive landraces DP-29 and DP-24, it was demonstrated that differences of tolerance to P-deficiency existed among different maize landraces. The results based on the correlation analysis showed that the economic yield of maize landraces had relationships with their morphological and physiological characteristics under P-deficiency.

Field identification of morphological and physiological traits in two special mutants with strong tolerance and high sensitivity to drought stress in upland rice(Oryza sativa L.)

The two mutants idr1-1 and 297-28, which were obtained from the radiation mutation of HD297 and IAPAR9, were used as experimental materials in this study for a 2-year(2012 and 2013) experiment about field drought resistance identification in Beijing, China. Key agronomic traits and water-related physiological indexes were observed and measured, including the leaf anti-dead level(LADL), days to heading, plant height, setting percentage, aboveground biomass, leaf water potential(LWP), net photosynthetic rate(Pn) and transpiration rate. The results showed that the mutant idr1-1 that was under drought stress(DS) conditions for 2 years had the highest LADL grades(1.3 and 2.0) among all the materials, and they were 2–3 grades stronger than the wild-type IAPAR9 with an average that was 21.4% higher for the setting percentage than the wild type. Compared with the IAPAR9 for the 2-year average delay in the days to heading and the reduction rates in the plant height, setting percentage, and aboveground biomass under DS compared with the well-watered(WW) treatment, idr1-1 showed 3.2% less delay and 19.1, 16.4, and 6.1% less reduction, respectively. The idr1-1 in the LWP always exhibited the highest performance among all the materials. The Pn of idr1-1 under severe and mild DS comparing with that under WW was slightly decreased and even slightly increased, respectively, leading to an average reduction rate of only 0.92%, which was 26.93% less than that of IAPAR9. Under the severe DS, idr1-1 still showed the highest value of 16.88 μmol CO2 m–2 s–1 among all the materials and was significantly higher than that of IAPAR9(11.66 μmol CO2 m–2 s–1). Furthermore, only idr1-1 had the increased and the highest transpiration rate values(7.6 and 6.04 mmol H2 O m–2 s–1) under both mild and severe DS compared with the values under WW, when the transpiration rate of all the other materials significantly decreased. By contrast, the 297-28 in terms of the LADL grade under DS was the lowest(7.0), and it was four grades weaker than its wildtype HD297 and even one grade weaker than the drought-sensitive paddy rice SN265. For the 2-year average reduction rates in aboveground biomass and plant heights under DS compared with those under the WW, 297-28 was 31.6 and 31.8% higher than HD297, respectively. Meanwhile, 297-28 showed the worst performance for the LWP, Pn, and transpiration rate. These results suggest that idr1-1 might be a superior drought tolerant mutant of upland rice found in China. It has a strong ability to maintain and even enhance leaf transpiration while maintaining a high plant water potential under DS, thus supporting a high Pn and alleviating the delay in agronomic trait development and yield loss effectively. 297-28 is a much more highly drought-sensitive mutant that is even more sensitive than paddy rice varieties. The two mutants could be used as drought tolerance controls for rice germplasm identification and the drought resistant mechanism studies in the future. idr1-1 is also suitable for breeding drought-tolerant and lodging-resistant high-yield rice varieties.

Effects of Drought Stress on Morphological and Physiological Indices of New Coix Varieties in Yunnan

In order to study the effects of drought stress on the morphological and physiological indexes of Yunnan Coix at different growth stages, two new varieties of Yunnan Coix Wenyi 4 and Wenyi 5 were used as experimental materials, potted and compared with CK by normal irrigation. Morphological indices such as plant height, stem diameter and physiological indices such as protein, soluble sugar, chlorophyll content and relative conductivity (REC) of the two varieties under drought stress at seedling stage, tillering stage and jointing stage were determined, and data statistics and variance analysis were performed for each index. The results showed that the morphological indices, plant height of Wenyi 4 and Wenyi 5 were significantly affected by drought stress at seedling stage, while the stem diameter was significantly affected by drought stress at seedling and jointing stage. In terms of physiological indices, the relative conductivity, protein and soluble sugar contents of Wenyi 5 increased at a higher degree, whereas chlorophyll content decreased at a higher degree, indicating that Wenyi 5 was greatly affected by drought stress. Through the analysis of drought resistance of the tested materials at different stages by polar ordination method, the results were as follows: jointing stage of Wenyi 5>jointing stage of Wenyi 4>seedling stage of Wenyi 4>seedling stage of Wenyi 5>tillering Stage of Wenyi 4>Tillering Stage of Wenyi 5. For the growth period, the drought resistance was as follows: jointing stage>seedling stage>tillering stage. In conclusion, Wenyi 4 has strong drought resistance and is suitable for droughtresistant cultivation.

Morphological and Physiological Differences in the Floral Organs of Hosui Pear(Pyrus pyrifolia Nakai) between Normal and Returning Bloom during Late Autumn

[Objective] This study was conducted to investigate the morphological and physiological differences between the flowers opening spring and late autumn of Hosui Asian pear（Pyrus pyrifolia Nakai）. [Method] Pear flowers were collected from normal bloom（NB） and returning bloom periods during late autumn in 2011-2013,respectively. The morphological and physiological indices including pollen number,germination rate, petal length, soluble protein content, soluble sugar content, amino acid content, pollen tube growth, fruiting characteristics of NB and RB flowers were detected and compared. [Result] The filament length and petal area of RB flowers were significantly smaller than those of NB flowers. The contents of soluble proteins, soluble sugars and amino acids of RB pollens were significantly smaller than those of NB flowers. In addition, the abortion rate of RB flowers was higher than that of NB flowers. [Conclusion] RB flowers had complete floral organs and were capable of pollination, but they were different from NB flowers in some morphological and physiological indices.

Morphological and physiological traits of large-panicle rice varieties with high filled-grain percentage

financed by the Special Program of Super Rice of Ministry of Agriculture, China （02318802013231）;the National Public Services Sectors （Agricultural） Research Projects, Ministry of Agriculture, China （201303102）;the Great Technology Project of Ningbo, China （2013C11001）

Morphological and physiological differences in heteromorphic leaves of male and female Populus euphratica Oliv.

Leaf traits can directly reflect the adaptation strategies of plants to the environment.However,there is limited knowledge on the adaptation strategies of heteromorphic leaves of male and female Populus euphratica Oliv.in response to individual developmental stages(i.e.,diameter class)and canopy height changes.In this study,morphological and physiological properties of heteromorphic leaves of male and female P.euphratica were investigated.Results showed that both male and female P.euphratica exhibited increased leaf area(LA),leaf dry weight(LDW),leaf thickness(LT),net photosynthetic rate(P_(n)),transpiration rate(T_(r)),stomatal conductance(g_(s)),proline(Pro),and malondialdehyde(MDA)concentration,decreased leaf shape index(LI)and specific leaf area(SLA)with increasing diameter and canopy height.Leaf water potential(LWP)increased with increasing diameter,LWP decreased significantly with increasing canopy height in both sexes,and carbon isotope fraction(δ^(13)C)increased significantly with canopy height in both sexes,all of which showed obvious resistance characteristics.However,males showed greater LA,LT,P_(n),T_(r),and Pro than females at the same canopy height,and males showed significantly higher LA,SLA,LT,P_(n),T_(r),g_(s),and MDA,but lower LWP and δ_(1)3C than females at the same canopy height,suggesting that male P.euphratica have stronger photosynthetic and osmoregulatory abilities,and are sensitive to water deficiency.Moreover,difference between male and female P.euphratica is closely related to the increase in individual diameter class and canopy height.In summary,male plants showed higher stress tolerance than female plants,and differences in P_(n),g_(s),T_(r),Pro,MDA,δ_(13)C,and LWP between females and males were related to changes in leaf morphology,diameter class,and canopy height.The results of this study provide a theory for the differences in growth adaptation strategies during individual development of P.euphratica.

Morphological and Physiological Traits of Assistance in the Selection of High Yielding Varieties of Durum Wheat (<i>Triticum turgidum</i>L. spp. Durum) for the Rainfed Mediterranean Environments of Central Chile

Chile has high potential to produce quality durum wheat;however, it is not self-sufficient. It is necessary to increase durum grain yield in the Mediterranean rainfed areas which are characterized by adverse environmental conditions, mainly, water deficit. The criteria normally used by breeders to select varieties of wheat for these environments are yield under stress and early flowering. The objective of this monograph is to propose that the selection of high yielding genotypes of durum wheat, under Chilean Mediterranean rainfed conditions, be assisted by morphological and physiological traits associated with yield in order to increase its heritability.

Physiological Response Mechanism and Drought Resistance Evaluation of Passiflora edulis Sims under Drought Stress

In order to explore the response mechanism of Passiflora edulis Sims to drought stress,the changes in morpho-logical and physiological traits of Passiflora edulis Sims under different drought conditions were studied.A total of 7 germplasm resources of Passiflora edulis Sims were selected and tested under drought stress by the pot culture method under 4 treatment levels:75%–80%(Control,CK)of maximumfield water capacity,55%–60%(Light Drought,LD)of maximumfield water capacity,i.e.,mild drought,40%–45%(Moderate Drought,MD)of max-imumfield water capacity,i.e.,moderate drought and 30%–35%(Severe Drought,SD)of maximumfield water capacity,i.e.,severe drought.On the 40th day of drought treatment,13 indices,including seedling growth mor-phology,physiology,and biochemistry,were measured.The results showed that under drought stress,the height and ground diameter of P.edulis Sims gradually decreased with increasing drought stress,and there were signifi-cant differences in seedling height and ground diameter among the treatments.Drought stress significantly inhib-ited the growth of seven P.edulis Sims varieties.The contents of soluble sugar(SS),soluble protein(SP),proline(Pro),and other substances in P.edulis Sims basically increased with increasing drought stress.With the aggrava-tion of drought stress,the malondialdehyde(MDA)content of P.edulis Sims tended to increase to different degrees,the superoxide dismutase(SOD)activity and peroxidase(POD)activity both tended to increase atfirst and then decrease,and the change in catalase(CAT)activity mostly showed a gradual increasing trend.The con-tents of endogenous hormones in P.edulis Sims significantly differed under different degrees of drought stress.With the aggravation of drought stress,the abscisic acid(ABA)content of P.edulis Sims tended to increase,whereas the contents of gibberellin(GA),indoleacetic acid(IAA),and zeatin nucleoside(ZR)exhibited a down-ward trend.A comprehensive evaluation of the drought resistance of seven P.edulis Sims varieties was conducted based on the principal component analysis method,and the results showed that the drought resistance decreased in the order XH-BL>XH-TWZ>TN1>GH1>ZJ-MT>LP-LZ>DH-JW.

鼠李糖脂对盐胁迫下棉花幼苗根系生长的调控作用

为探究鼠李糖脂(rhamnolipids,RLS)对盐胁迫下棉花幼苗生理生长的缓解作用,设置低盐(3 g·L^(-1)Na Cl,T1)和高盐(6 g·L^(-1)Na Cl,T2)2个盐梯度,0(R_(0))、200(R_(1))、300(R_(2))和400 mg·L^(-1)(R_(3))4个RLS梯度,分析盐胁迫下施加RLS对棉花幼苗根系形态、抗氧化酶及渗透调节物质的影响。结果表明,盐胁迫下适宜水平的RLS可促进棉花幼苗根系总长度、表面积和根尖数的增长。在低盐胁迫下,棉花幼苗根系超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)、过氧化氢酶(catalase,CAT)活性和脯氨酸(proline,Pro)、可溶性糖(soluble sugars,SS)含量随RLS含量升高呈先增大后减小的趋势,其中T_(1)R_(2)处理各项指标较T_(1)R_(0)分别提高14.0%、15.2%、28.8%、28.5%和19.5%;在高盐胁迫下,棉花幼苗根系SOD、POD、CAT活性和Pro、SS含量随RLS含量升高呈逐渐减小的趋势,其中T2R_(1)较T_(2)R_(0)处理分别提高10.5%、12.6%、13.9%、21.7%和4.8%。主成分分析表明,盐胁迫下棉花幼苗根系表面积、SOD和Pro对RLS的调控响应度较高,可作为盐胁迫下RLS对棉花幼苗生理生长调控的主要控制指标。综合评价得出,低盐胁迫下施用RLS提升棉花幼苗耐盐性的最适宜量为300 mg·L^(-1),而高盐胁迫下RLS的最佳施用量为200 mg·L^(-1)。以上研究结果为棉花耐盐抗逆种植提供了适宜的外源施用策略。

水稻对弱光胁迫的响应及适应机制研究进展

水稻是我国最重要的粮食作物之一,光照对其产量和品质形成具有重要影响。随着全球气候恶化,阴雨寡照天气频发,随之带来的弱光胁迫已成为影响水稻高产稳产、优质生产的重要限制因素。水稻安全稳定、可持续生产对保障我国粮食安全、满足人们对粮食的需求具有重要意义。因此,本文对近些年的研究成果进行总结,综述了弱光胁迫对水稻根茎叶和花器官的形态特征、光合特性、花粉受精、同化物转运和淀粉合成酶的生理特征,氮代谢、激素调节、光受体调节、抗氧化系统和渗透调节的生化特征,以及对产量和品质的影响,重点关注水稻对弱光胁迫的分子响应机制;并展望未来水稻耐荫性研究的方向和热点,指出未来要更加深入研究水稻在遗传水平上对弱光胁迫的适应机制以及相关耐荫基因的挖掘。本研究旨在全面了解水稻耐荫分子响应机制,为选育耐荫品种提供新的思路和策略。

低磷胁迫下不同耐受型谷子的代谢组学差异

【目的】谷子具有较强的耐瘠薄特性,探索谷子响应低磷胁迫的根系形态与生理代谢变化,对于了解谷子耐低磷机制具有重要意义。【方法】以耐低磷型种质B254和低磷敏感型种质B171为试材进行水培试验,设置正常和低磷Hoagland营养液两个处理,KH2PO4浓度分别为0.25、0.0025 mmol/L。幼苗在营养液中处理7、14天时,取样分析农艺性状、根系形态、磷含量、生理酸性磷酸酶(ACP)活性,利用LC-MS/MS技术分析叶片和根系的代谢物,以VIP>1、|log2(FC)|≥1和P<0.05为条件筛选差异代谢物,并利用KEGG代谢通路数据库分析差异代谢物主要存在的代谢途径。【结果】在低磷条件下,谷子株高显著降低了32.8%,根系磷含量降低可达75.84%,但耐受型B254总根长、根表面积分别显著增加了33.7%、59.5%,表现出较强的耐低磷特性。同时,叶绿素、花青素和酸性磷酸酶(ACP)活性在低磷条件下也显著增加,其中B254的叶片与根系ACP活性分别显著增加了91.83%与22.91%。相关性分析结果表明,在低磷条件下株高、根系发育与生理适应性状之间的相关性显著增强。代谢组学差异分析结果显示,低磷胁迫下不同低磷耐受型谷子代谢产物类型存在较大差异,其中B171在叶片和根系中积累了大量的黄酮、萜类和脂质,而B254的差异代谢物主要为氨基酸和脂质,尤其是特殊酯类磷脂合成前体溶血磷脂酸积累。KEGG代谢通路分析发现,低磷胁迫显著富集了谷子叶片的嘌呤代谢和根系苯丙氨酸代谢。【结论】低磷胁迫诱导谷子耐低磷种质提高了酸性磷酸酶活性,提升了花青素含量,并促进了黄酮、氨基酸、脂类等代谢物的合成,尤其是对类磷脂合成前体如溶血磷脂酸的累积起到极为关键的作用,产生的差异代谢物主要出现在嘌呤代谢和苯丙氨酸代谢途径。

Physiological and molecular responses to cold stress in rapeseed(Brassica napus L.)

Low temperature is one of the most important abiotic factors inhibiting growth, productivity, and distribution of rapeseed(Brassica napus L.). Therefore, it is important to identify and cultivate cold-tolerant germplasm. The objective of this study was to figure out the mechanism of chilling(4 and 2°C) and freezing(–2 and –4°C) stresses along with a control(22°C) in B. napus cultivars(1801 and C20) under controlled environment(growth chamber). The experiment was arranged in a complete randomized design with three replications. Our results exhibited that under chilling and freezing stresses, the increment of proline accumulation, soluble sugar and protein contents, and antioxidant enzyme activity were enhanced more in 1801 cultivar compared with C20 cultivar. At –2 and –4°C, the seedlings of C20 cultivar died completely compared with 1801 cultivar. Hydrogen peroxide(H2 O2) and malondialdehyde contents(MDA) increased in both cultivars, but when the temperature was decreased up to –2 and –4°C, the MDA and H2 O2 contents continuously dropped in 1801 cultivar. Moreover, we found that leaf abscisic acid(ABA) was enhanced in 1801 cultivar under chilling and freezing stresses. Additionally, the transcriptional regulations of cold-tolerant genes(COLD1, CBF4, COR6.6, COR15, and COR25) were also determined using real-time quantitative PCR(RT-q PCR). RT-q PCR showed that higher expression of these genes were found in 1801 as compared to C20 under cold stress(chilling and freezing stresses). Therefore, it is concluded from this experiment that 1801 cultivar has a higher ability to respond to cold stress(chilling and freezing stresses) by maintaining hormonal, antioxidative, and osmotic activity along with gene transcription process than C20. The result of this study will provide a solid foundation for understanding physiological and molecular mechanisms of cold stress signaling in rapeseed(B. napus).

Effect of different water supply on morphology, growth and physiological characteristics of Salix psammophila seedlings in Maowusu sandland, China

Response pattern was investigated for seedlings of Salix psammophila, a dominant shrub in Maowusu sandland, to the simulated precipitation change by artificially controlling water supply at four levels. The growth characters, in terms of plant height, stem diameter, total branch number, total leaf number and area, total bifurcation ratio, total branch lenght and branch number, branch lenght, leaf number and leaf area of each branch order, and leaf, branch and root biomass significantly increased when water supply increased. That water supply had significant effect on biomass allocation showed different investment pattern of biomass resource of the seedlings grown under different water supply treatments. Stomatal density of abaxial leaf surface decreased, and stomatal apparatus length and width of adaxial and abaxial leaf surface increased with the increase of water supply, while Stomatal density of adaxial leaf surface was not affected by water supply. Water supply obviously affected the diumal changes of photosynthetic rate, and the photosynthetic rate of the seedlings showed strongly midday depression grown under the 157.5 mm water supply, but not grown under higher water supply. Additionally the assimilation-light response curves and flourescence efficiency more showed that water supply improve photosynthesis capacity. Finally, S. psammophila seedlings stood out by their slow growth and relatively high investments in root growth in order to reduce tissue losing rate and consumption of water resource for keeping water balance under water stress. The seedlings that grown under rich water supply did by their fast growth and relatively high investments in branch and leaf growth in order to improve the power of capturing light energy for higher photosynthesis.

Three-dimensional analysis of the physiological foramen geometry of maxillary and mandibular molars by means of micro-CT

The aim of this study was to investigate the physiological foramen diameter, shape and distance between physiological and anatomical apex of maxillary and mandibular first and second molars. Accurate knowledge of the physiological foramina morphology; thus, inherent mechanical shaping technical hindrances, is decisive when taking the corresponding root canal final preparation decision. The morphological dimensions of a total of 1 727 physiological foramina were investigated by means of micro-computed tomography. Mean narrow and wide （to a high number, oval） diameters of the physiological foramen were 0.24, 0.22 and 0.33 mm and 0.33, 0.31 and 0.42 mm in mesiobuccal （MB）, distobuccal （DB） and palatal （P） roots in maxillary first molars; 0.24, 0.22 and 0.33 mm and 0.41, 0.33 and 0.44 in MB, DB, and P roots in maxillary second molars. Mandibular first molars showed mean narrow and wide diameters of 0.24 and 0.30 mm and of 0.39 and 0.46 mm in mesial （M） and distal （D） roots; second mandibular molars showed 0.25 and 0.31 mm and 0.47 mm in M and D roots. The mean distance between the physiological foramina and anatomical apex was 0.82, 0.81 and 1.02 mm and 0.54, 0.43 and 0.63 mm in MB, DB and P roots of the maxillary first and second molars, respectively. A mean distance of 0.95 mm （M） and 1.05 mm （D） in the first and 0.78 mm （M） and 0.81 mm （D） in the second mandibular molars was observed. Based on the results obtained, assumable recommendations for final preparation size of the physiological foramen were calculated. However, when taking into consideration, the resulting standard deviations of marginal errors must be cautiously considered when taking a final decision in clinical endodontic treatment.

Deciphering the morpho–physiological traits for high yield potential in nitrogen efficient varieties(NEVs):A japonica rice case study

The use of nitrogen(N)-efficient rice(Oryza sativa L.) varieties could reduce excessive N input without sacrificing yields. However, the plant traits associated with N-efficient rice varieties have not been fully defined or comprehensively explored. Here, three japonica N-efficient varieties(NEVs) and three japonica N-inefficient varieties(NIVs) of rice were grown in a paddy field under N omission(0 N, 0 kg N ha^(-1)) and normal N(NN, 180 or 200 kg N ha^(-1)) treatments. Results showed that NEVs exhibited higher grain yield and nitrogen use efficiency(NUE) than NIVs under both treatments, due to improved sink size and filled-grains percentage in the former which had higher root oxidation activity and greater root dry weight, root length and root diameter at panicle initiation(PI), as well as higher spikelet-leaf ratio and more productive tillers during the grain-filling stage. Compared with NIVs, NEVs also exhibited enhanced N translocation and dry matter accumulation after heading and improved flag leaf morpho-physiological traits, including greater leaf thickness and specific leaf weight and higher contents of ribulose^(-1),5-bisphosphate carboxylase/oxygenase, chlorophyll, nitrogen, and soluble sugars, leading to better photosynthetic performance. Additionally, NEVs had a better canopy structure, as reflected by a higher ratio of the extinction coefficient for effective leaf N to the light extinction coefficient, leading to enhanced canopy photosynthesis and dry matter accumulation. These improved agronomic and physiological traits were positively and significantly correlated with grain yield and internal NUE, which could be used to select and breed N-efficient rice varieties.

Synergistic combination of arbuscular mycorrhizal fungi and plant growth-promoting rhizobacteria modulates morpho-physiological characteristics and soil structure in Nitraria tangutorum bobr.Under saline soil conditions

Nitraria tangutorum Bobr.,a typical xero-halophyte,can be used for vegetation restoration and reconstruction in arid and semiarid regions affected by salinity.However,global climate change and unreasonable human activity have exacerbated salinization in arid and semi-arid regions,which in turn has led to the growth inhibition of halophytes,including N.tangutorum.Arbuscular mycorrhizal fungi(AMF)and plant growth-promoting rhizobacteria(PGPR)have the potential to improve the salt tolerance of plants and their adaptation to saline soil environments.In this study,the effects of single and combined inoculations of AMF(Glomus mosseae)and PGPR(Bacillus amyloliquefaciens FZB42)on N.tangutorum were evaluated in severe saline soil conditions.The results indicate that AMF and PGPR alone may not adapt well to the real soil environment,and cannot ensure the effect of either growth promotion or salt-tolerance induction on N.tangutorum seedlings.However,the combination of AMF and PGPR significantly promoted mycorrhizal colonization,increased biomass accumulation,improved morphological development,enhanced photosynthetic performance,stomatal adjustment ability,and the exchange of water and gas.Co-inoculation also significantly counteracted the adverse effect of salinity on the soil structure of N.tangutorum seedlings.It is concluded that the effectiveness of microbial inoculation on the salt tolerance of N.tangutorum seedlings depends on the functional compatibility between plants and microorganisms as well as the specific combinations of AMF and PGPR.

Morpho-Physiological Characterization of Winter Wheat “Buster” Population during the Vegetative Stage under Heat Stress

Phenotypic assessment of breeding population is important to identify robust lines for incorporating into future breeding programs. The objective of this study was to identify potential lines from a wheat (Triticum aestivum L.) population, based on their morpho-physiological traits, for improved heat tolerance. A subset of 100 lines of the double haploid (DH) population named “Buster”, developed from two successful Oklahoma wheat varieties (Billings and Duster), was used in the study. Two experiments were conducted one in a greenhouse and the other in growth chambers. Data on plant height, tiller number, leaf number, and photosynthetic pigments were collected from the greenhouse;whereas the data on physiological parameters (leaf net photosynthesis (Pn), transpiration (T), stomatal conductance (gs), intercellular carbon dioxide concentration (Ci), electron transport rate (ETR), Photosystem II efficiency (Fv'/Fm') and instantaneous water use efficiency (IWUE)) were collected from the growth chambers. Buster lines were significantly (P < 0.05) different both morphologically and physiologically. A wide range of observations among genotypes for different morphological and physiological characteristics was found. For example, the Chlorophyll A:B ratio ranged from 1.8 to 4.3, average plant height ranged from 8.4 to 13.3 cm, and the net photosynthesis under heat stress ranged from 11.29 to 25.28 μmol CO2 m-2·s-1. The differences in leaf physiological parameters were more discernible under heat stress. This study provides a piece of baseline information on morpho-physiological characteristics of Buster lines, and identified lines can be used in future breeding programs for incorporating heat stress tolerance.

不同直插型基质对3种盆栽菊花生长的影响以及综合评价

为提高盆栽菊花(Chrysanthemum morifolium)扦插繁殖的成活率,提高菊花生产效率,以既有扦插基质又有营养基质的直插型基质代替传统栽培基质,设置了12种不同扦插基质,配合前期筛选的营养基质,扦插培养3种盆栽菊花‘辉煌’‘波尔多红’‘黄芙蓉’。测量其生长、生理以及光合指标,并利用主成分分析和隶属函数对不同直插型基质的盆栽菊花生长效果进行综合评价。结果表明:扦插基质为Z1(河沙)、Z2(珍珠岩)、Z3(蛭石)时,3个盆栽菊花品种的株高、茎粗、冠幅及花期等生长指标更具优势。‘辉煌’‘波尔多红’‘黄芙蓉’在Z2处理中的综合评价指数最高,分别为0.999、0.940、1.000,说明其育苗效果最好,可作为最佳直插型基质,其次为Z1、Z3处理。而扦插基质中,椰糠、稻壳和泥炭体积占比较大时,并不利于盆栽菊花的生长。

Assessment of Salinity Tolerance and Ecotypic Variability in Vicia narbonensis L.:Morphological,Physiological,and Biochemical Responses

Salinity stress is a major challenge for global agriculture,particularly in arid and semi-arid regions,limiting plant productivity due to water and soil salinity.These conditions particularly affect countries along the southern Mediterranean rim,including Algeria,which primarily focuses on pastoral and forage practices.This study investigates salinity tolerance and ecotypic variability in Vicia narbonensis L.,a fodder legume species recognized for its potential to reclaim marginal soils.Morphological,physiological,and biochemical responses were assessed in three ecotypes(eco2,eco9,and eco10)exposed to different salinity levels(low,moderate,and severe).The study was conducted using a completely randomized block design with three blocks per ecotype per dose.The results from the two-way analysis of variance demonstrate significant effects across nearly all attributes studied,revealing distinct ecotypic responses.These findings underscore variations in growth parameters,osmotic regulation mechanisms,and biochemical adjustments.The substantial diversity observed among these ecotypes in their response to salinity provides valuable insights for breeders addressing both agronomic and ecological challenges.Multivariate analyses,including Principal Component Analysis(PCA),revealed key variables distinguishing between ecotypes under salinity stress.Moreover,Classification based on Salinity Tolerance Indices(STI)further differentiated ecotypic performance with more precision,and this is because of the combination of the different parameters studied.These results open up new prospects for the development of strategies to improve the salinity tolerance of forage legumes.