Arbuscular mycorrhizal influence on growth,photosynthetic pigments,osmotic adjustment and oxidative stress in tomato plants subjected to low temperature stress

The influence of the arbuscular mycorrhizal (AM) fungus, Glomus mosseae, on characteristics of growth, photosynthetic pigments, osmotic adjustment, membrane lipid peroxidation and activity of antioxidant enzymes in leaves of tomato (Lycopersicon esculentum cv Zhongzha105) plants was studied in pot culture under low temperature stress. The tomato plants were placed in a sand and soil mixture at 25°C for 6 weeks, and then subjected to 8°C for 1 week. AM symbiosis decreased malondialdehyde (MDA) content in leaves. The contents of photosynthetic pigments, sugars and soluble protein in leaves were higher, but leaf proline content was lower in mycorrhizal than non-mycorrhizal plants. AM colonization increased the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) in leaves. The results indicate that the AM fungus is capable of alleviating the damage caused by low temperature stress on tomato plants by reducing membrane lipid peroxidation and increasing the photosynthetic pigments, accumulation of osmotic adjustment compounds, and antioxidant enzyme activity. Consequently, arbuscular mycorrhiza formation highly enhanced the cold tolerance of tomato plant, which increased host biomass and promoted plant growth.     

Effects of Arbuscular Mycorrhizal Fungi on Physiological Characterof Bahia Grass (Paspalum notatum,Poaceae)

The effects of arbuscular mycorrhizal (AM) fungus, Glomus mosseae, on growth, osmotic adjustment and antioxidant enzymes of bahia grass (Paspalum notatum) were studied in potted plants under water stress conditions. AM colonization significantly enhanced the plant height, root and shoot fresh weight, Phosphorus (P), potasium (K), manganese (Mn) contents in shoots, P, calcium (Ca), Mn contents in roots, whereas obviously decreased zinc (Zn) content in shoots, iron (Fe), boron (B), copper (Cu) contents in roots. During water stress, the relative water and chlorophyll contents were relatively stable and signifciantly higher in AM than in non-AM plants, AM inoculation notabley decreased the shoot relative conductivity and malondialdehyde (MDA) content, markedly increased shoot peroxidase (POD) activity and proline content, while AM infection did not affect the dismutase (SOD) activity of shoots. Our results suggested that AM colonization improved the protective enzyme activity (such as POD) and osmotic adjustment originating from proline P, K, Ca, resulting in the enhancement of drought tolerance.     

丛枝菌根真菌对百喜草的生理特性的影响

采用盆栽法研究了丛枝菌根（AM）真菌摩西球囊霉（Glomus mosseae）对水分胁迫条件下百喜草（Paspalum notatum）生长、渗透调节及抗氧化酶的影响。结果表明：接种AM真菌显著提高了百喜草的株高、地上部与根部鲜重、地上部P、K、Mn及根部P、Ca、Mn含量,明显降低了地上部Zn及根部Fe、B、Cu水平;随着干旱程度的加深,接种株的地上部相对含水量及叶绿素含量相对稳定且均显著高于未接种株,接种株地上部相对电导率、MDA含量均显著低于未接种株,接种株的地上部POD活性与脯氨酸含量均显著增加且均显著高于未接种株,AM侵染对SOD活性的影响较小。可见,接种AM真菌Glomus mosseae提高了植株体内保护酶活性（如POD）及渗透调节能力（如脯氨酸、P、K、Ca等渗透调节物含量的增加）,从而显著增强了百喜草的抗旱性。     

丛枝菌根真菌对百喜草的生理特性的影响

采用盆栽法研究了丛枝菌根（AM）真菌摩西球囊霉（Glomus mosseae）对水分胁迫条件下百喜草（Paspalum notatum）生长、渗透调节及抗氧化酶的影响。结果表明：接种AM真菌显著提高了百喜草的株高、地上部与根部鲜重、地上部P、K、Mn及根部P、Ca、Mn含量,明显降低了地上部Zn及根部Fe、B、Cu水平;随着干旱程度的加深,接种株的地上部相对含水量及叶绿素含量相对稳定且均显著高于未接种株,接种株地上部相对电导率、MDA含量均显著低于未接种株,接种株的地上部POD活性与脯氨酸含量均显著增加且均显著高于未接种株,AM侵染对SOD活性的影响较小。可见,接种AM真菌Glomusmossecte提高了植株体内保护酶活性（如POD）及渗透调节能力（如脯氨酸、P、K、Ca等渗透调节物含量的增加）,从而显著增强了百喜草的抗旱性。     

Arbuscular mycorrhizal fungi influence growth, osmotic adjustment and photosynthesis of citrus under well-watered and water stress conditions

The influence of arbuscular mycorrhizal (AM) fungus Glomus versiforme on plant growth, osmotic adjustment and photosynthesis of tangerine (Citrus tangerine) were studied in potted culture under well-watered and water stress conditions. Seven-day-old seedlings of tangerine were transferred to pots containing Glomus versiforme or non-AMF. After 97 days, half of the seedlings were subject to water stress and the rest were well-watered for 80 days. AM colonization significantly stimulated plant growth and biomass regardless of water status. The soluble sugar of leaves and roots, the soluble starch of leaves, the total non-structural carbohydrates (NSC) of leaves and roots, and the Mg(2+) of leaves were higher in AM seedlings than those in corresponding non-AM seedlings. The levels of K(+) and Ca(2+) in leaves and roots were higher in AM seedlings than those in non-AM seedlings, but differences were only significant under water stress conditions. Moreover, AM colonization increased the distributed proportions of soluble sugar and NSC to roots. However, the proline was lower in AM seedlings compared with that in non-AM seedlings. AM seedlings had higher leaf water potential (Psi), transpiration rates (E), photosynthetic rates (Pn), stomatal conductance (g(s)), relative water content (RWC), and lower leaf temperature (Lt) than corresponding non-AM seedlings. This research also suggested that AM colonization improved the osmotic adjustment originating not from proline but from NSC, K(+), Ca(2+) and Mg(2+), resulting in the enhancement of drought tolerance.     

Effects of arbuscular mycorrhizal fungus on photosynthesis and water status of maize under high temperature stress

The purpose of this study was to investigate the effects of arbuscular mycorrhizal (AM) symbiosis on gas exchange, chlorophyll fluorescence, pigment concentration and water status of maize plants in pot culture under high temperature stress. Zea mays L. genotype Zhengdan 958 were cultivated in soil at 26/22°C for 6 weeks, and later subjected to 25, 35 and 40°C for 1 week. The plants inoculated with the AM fungus Glomus etunicatum were compared with the non-inoculated plants. The results showed that high temperature stress decreased the biomass of the maize plants. AM symbiosis markedly enhanced the net photosynthetic rate, stomatal conductance and transpiration rate in the maize leaves. Compared with the non-mycorrhizal plants, mycorrhizal plants had lower intercellular CO₂ concentration under 40°C stress. The maximal fluorescence, maximum quantum efficiency of PSII photochemistry and potential photochemical efficiency of mycorrhizal plants were significantly higher than corresponding non-mycorrhizal plants under high temperature stress. AM-inoculated plants had higher concentrations of chlorophyll a, chlorophyll b and carotenoid than non-inoculated plants. Furthermore, AM colonization increased water use efficiency, water holding capacity and relative water content. In conclusion, maize roots inoculated with AM fungus may protect the plants against high temperature stress by improving photosynthesis and water status.     

Arbuscular mycorrhizal inoculation improves growth and antioxidative response of Jatropha curcas (L.) under Na2SO4 salt stress

This study investigated the effect of arbuscular mycorrhizal (AM) fungal consortia on growth, photosynthetic pigments, solutes concentration (e.g., sugars and proline), and antioxidant responses at different levels of Na₂SO₄ stress (0–0.5%, w:w) in potted culture of Jatropha. Results showed that increasing salt levels caused a significant reduction in survival (%), growth parameters, leaf relative water content (LRWC) (%), and chlorophyll content with an increase in electrolyte leakage (%) and lipid peroxidation of membranes of Jatropha. AM inoculation improved biomass yields as well as other physiological parameters (LRWC (%), chlorophyll, proline, and soluble sugar) of salt-stressed Jatropha over noninoculated plants. Tolerance index of Jatropha was higher with AM fungi than without at all salt levels; however, a decline in its value was recorded with increased salinity levels. AM inoculation also enhanced the activities of antioxidant enzymes (e.g., superoxide dismutase, peroxidase, ascorbate peroxidase, and glutathione reductase) and decreased oxidative damage to lipids. In conclusion, results indicate that AM inoculation was capable of alleviating the damage caused by salinity stress on Jatropha plants by reducing lipid peroxidation of membrane and membrane permeability and increasing the accumulation of solutes and antioxidant enzyme activity.     

Sex-Related Responses of Populus cathayana Shoots and Roots to AM Fungi and Drought Stress

We investigated the impact of drought and arbuscular mycorrhizal (AM) fungi on the morphological structure and physiological function of shoots and roots of male and female seedlings of the dioecious plant Populus cathayana Rehder. Pot-grown seedlings were subjected to well watered or water-limiting conditions (drought) and were grown in soil that was either inoculated or not inoculated with the AM fungus Rhizophagus intraradices. No significant differences were found in the infection rates between the two sexes. Drought decreased root and shoot growth, biomass and root morphological characteristics, whereas superoxide radical (O₂–) and hydrogen peroxide content, peroxidase (POD) activity, malondialdehyde (MDA) concentration and proline content were significantly enhanced in both sexes. Male plants that formed an AM fungal symbiosis showed a significant increase in shoot and root morphological growth, increased proline content of leaves and roots, and increased POD activity in roots under both watering regimes; however, MDA concentration in the roots decreased. By contrast, AM fungi either had no effect or a slight negative effect on the shoot and root growth of female plants, with lower root biomass, total biomass and root/shoot ration under drought. In females, MDA concentration increased in leaves and roots under both watering regimes, and the proline content and POD activity of roots increased under drought conditions; however, POD activity significantly decreased under well-watered conditions. These findings suggest that AM fungi enhanced the tolerance of male plants to drought by improving shoot and root growth, biomass and the antioxidant system. Further investigation is needed to unravel the complex effects of AM fungi on the growth and antioxidant system of female 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.     

Improved tolerance of maize plants to salt stress by arbuscular mycorrhiza is related to higher accumulation of soluble sugars in roots

The effect of colonization with the arbuscular mycorrhizal (AM) fungus Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe on the growth and physiology of NaCl-stressed maize plants ( Zea mays L. cv. Yedan 13) was examined in the greenhouse. Maize plants were grown in sand with 0 or 100 mM NaCl and at two phosphorus (P) (0.05 and 0.1 mM) levels for 34 days, following 34 days of non-saline pre-treatment. Mycorrhizal plants maintained higher root and shoot dry weights. Concentrations of chlorophyll, P and soluble sugars were higher than in non-mycorrhizal plants under given NaCl and P levels. Sodium concentration in roots or shoots was similar in mycorrhizal and non-mycorrhizal plants. Mycorrhizal plants had higher electrolyte concentrations in roots and lower electrolyte leakage from roots than non-mycorrhizal plants under given NaCl and P levels. Although plants in the low P plus AM fungus treatment and those with high P minus AM fungus had similar P concentrations, the mycorrhizal plants still had higher dry weights, soluble sugars and electrolyte concentrations in roots. Similar relationships were observed regardless of the presence or absence of salt stress. Higher soluble sugars and electrolyte concentrations in mycorrhizal plants suggested a higher osmoregulating capacity of these plants. Alleviation of salt stress of a host plant by AM colonization appears not to be a specific effect. Furthermore, higher requirement for carbohydrates by AM fungi induces higher soluble sugar accumulation in host root tissues, which is independent of improvement in plant P status and enhances resistance to salt-induced osmotic stress in the mycorrhizal plant.     

Effects of drought on non-mycorrhizal and mycorrhizal maize: changes in the pools of non-structural carbohydrates, in the activities of invertase and trehalase, and in the pools of amino acids and imino acids

To study the response of non-mycorrhizal and mycorrhizal maize plants to drought, the changes in the pools of non-structural carbohydrates and amino acids were analysed in leaves and roots of two maize cvs. Plants well colonized by the arbuscular mycorrhizal fungus Glomus mosseae (Nicol. & Gerd.) (60% of root length infected) and comparable non-mycorrhizal plants were subjected to moderate drought stress by reducing the water supply. This stress induced a conspicuous increase in the trehalose pool in the mycorrhizal roots, probably because it was accumulated by the fungal symbiont. Furthermore, glucose and fructose were accumulated in leaves and roots of non-mycorrhizal plants but not in the mycorrhizal ones. Starch disappeared completely from the leaves of both mycorrhizal and non-mycorrhizal plants in response to drought. Activities of soluble acid invertase and trehalase were also measured. Acid invertase activity increased during drought in the leaves of both non-mycorrhizal and mycorrhizal plants whilst in the roots it was unaffected in non-mycorrhizal plants and decreased in the mycorrhizal ones. Without drought stress, trehalase activity was considerably higher in the leaves and roots of mycorrhizal plants than in those of non-mycorrhizal plants. It increased conspicuously during drought, primarily in the leaves of non-mycorrhizal plants. A drought-induced accumulation of amino acids as well as imino acids was found in roots and leaves of both mycorrhizal and non-mycorrhizal plants; leaves of mycorrhizal plants accumulated more imino acids than those of non-mycorrhizal ones. Our results show that drought stress and the presence of a mycorrhizal fungus have a considerable effect on carbon partitioning, imino acid and amino acid accumulation in maize plants.     

Osmotic solute responses of mycorrhizal citrus (<Emphasis Type="Italic">Poncirus trifoliata</Emphasis>) seedlings to drought stress

This study investigated the accumulation of osmotic solutes in citrus (Poncirus trifoliata) seedlings colonized by Glomus versiforme subjected to drought stress or kept well watered. Development of mycorrhizae was higher under well watered than under drought-stressed conditions. Arbuscular mycorrhizal (AM) seedlings accumulated more soluble sugars, soluble starch and total non-structural carbohydrates in leaves and roots than corresponding non-AM seedlings regardless of soil-water status. Glucose and sucrose contents of well-watered and drought-stressed roots, fructose contents of well-watered roots and sucrose contents of drought-stressed leaves were notably higher in AM than in non-AM seedlings. K⁺ and Ca²⁺ levels in AM leaves and roots were greater than those in non-AM leaves and roots, while AM symbiosis did not affect the Mg²⁺ level. AM seedlings accumulated less proline than non-AM seedlings. AM symbiosis altered both the allocation of carbohydrate to roots and the net osmotic solute accumulations in response to drought stress. It is concluded that AM colonization enhances osmotic solute accumulation of trifoliate orange seedlings, thus providing better osmotic adjustment in AM seedlings, which did not correlate with proline but with K⁺, Ca²⁺, Mg²⁺, glucose, fructose and sucrose accumulation.     

Arbuscular mycorrhizal influence on leaf water potential, solute accumulation, and oxidative stress in soybean plants subjected to drought stress

This study investigated several aspects related to drought tolerance in arbuscular mycorrhizal (AM) soybean plants. The investigation included both shoot and root tissues in order to reveal the preferred target tissue for AM effects against drought stress. Non-AM and AM soybean plants were grown under well-watered or drought-stressed conditions, and leaf water status, solute accumulation, oxidative damage to lipids, and other parameters were determined. Results showed that AM plants were protected against drought, as shown by their significantly higher shoot-biomass production. The leaf water potential was also higher in stressed AM plants (-1.9 MPa) than in non-AM plants (-2.5 MPa). The AM roots had accumulated more proline than non-AM roots, while the opposite was observed in shoots. Lipid peroxides were 55% lower in shoots of droughted AM plants than in droughted non-AM plants. Since there was no correlation between the lower oxidative damage to lipids in AM plants and the activity of antioxidant enzymes, it seems that first the AM symbiosis enhanced osmotic adjustment in roots, which could contribute to maintaining a water potential gradient favourable to the water entrance from soil into the roots. This enabled higher leaf water potential in AM plants during drought and kept the plants protected against oxidative stress, and these cumulative effects increased the plant tolerance to drought.     

Tolerance of Mycorrhiza infected pistachio (Pistacia vera L.) seedling to drought stress under glasshouse conditions

The influence of Glomus etunicatum colonization on plant growth and drought tolerance of 3-month-old Pistacia vera seedlings in potted culture was studied in two different water treatments. The arbuscular mycorrhiza (AM) inoculation and plant growth (including plant shoot and root weight, leaf area, and total chlorophyll) were higher for well-watered than for water-stressed plants. The growth of AM-treated seedlings was higher than non-AM-treatment regardless of water status. P, K, Zn and Cu contents in AM-treated shoots were greater than those in non-AM shoots under well-watered conditions and drought stress. N and Ca content were higher under drought stress, while AM symbiosis did not affect the Mg content. The contents of soluble sugars, proteins, flavonoid and proline were higher in mycorrhizal than non-mycorrhizal-treated plants under the whole water regime. AM colonization increased the activities of peroxidase enzyme in treatments, but did not affect the catalase activity in shoots and roots under well-watered conditions and drought stress. We conclude that AM colonization improved the drought tolerance of P. vera seedlings by increasing the accumulation of osmotic adjustment compounds, nutritional and antioxidant enzyme activity. It appears that AM formation enhanced the drought tolerance of pistachio plants, which increased host biomass and plant growth.     

AM真菌对盐胁迫下番茄幼苗生理特征及AVP1表达的影响

采用温室盆栽试验研究不同NaCl浓度（0、50 和85 mmol/L）持续胁迫接种摩西球囊霉和地表球囊霉 2种AM真菌对加工番茄耐盐性的影响。结果显示:（1）在0 mmol/L NaCl处理条件下,2种菌的番茄菌根化苗的根系活力、叶片中可溶性糖、可溶性蛋白、根系脯氨酸含量以及超氧化物歧化酶和过氧化物酶活性均高于非菌根植株,且丙二醛含量低于非菌根植株,但差异不显著。（2）在50、85 mmol/L NaCl浓度胁迫下,接种2种菌根真菌可显著提高番茄植株根系活力,促进叶片中可溶性糖、可溶性蛋白及根系脯氨酸含量的积累,显著提高叶片中与抗逆相关的超氧化物歧化酶和过氧化物酶的活性,减少丙二醛在根系中的积累;随着NaCl浓度的增加,效果更为明显。（3）RT-PCR分析显示,AM真菌和盐胁迫共同调控H⁺转运无机焦磷酸酶H⁺- PPase的表达,随NaCl浓度的增加,AVP1基因表达量下降,但菌根化番茄植株的AVP1基因表达量显著高于非菌根植株。研究表明,接种AM真菌后,菌根化植株可通过显著促进幼苗体内渗透调节物质积累和抗氧化酶活性的提高,有效降低体内膜脂过氧化水平,同时过量表达AVP1基因增加了番茄植株中离子向液泡膜的转运,从而缓解盐胁迫对植株的伤害,增强番茄幼苗对盐胁迫的耐性。     

How do Mycorrhizas Affect C and N Relationships in Flooded Aster tripolium Plants?

The mycorrhizal associations established between plants and fungi have multiple effects on plant growth, directly affecting stress tolerance. This work aimed to explore arbuscular mycorrhizal (AM) effects on carbon and nitrogen relationships of Aster tripolium L. and consequently on its flooding tolerance. Mycorrhizal and non-mycorrhizal juvenile plants were submitted to non-flooding and tidal flooding conditions for 56 d. Tidal flooding reduced biomass, but the presence of mycorrhiza had an ameliorating effect. The AM symbioses seem to have, like flooding, a stressful effect on A. tripolium at an early stage of plant development. However, once the plant was established, an improvement of growth performance of plants with mycorrhiza under flooding conditions was observed. The better tolerance of AM plants to flooding was mediated through an improvement of the osmotic adjustment of the plant tissues (higher concentrations of soluble sugars and proline) and through the increment of nitrogen acquisition in tidal-flooded plants.     

Localized and non‐localized effects of arbuscular mycorrhizal symbiosis on accumulation of osmolytes and aquaporins and on antioxidant systems in maize plants subjected to total or partial root drying

The arbuscular mycorrhizal (AM) symbiosis alters host plant physiology under drought stress, but no information is available on whether or not the AM affects respond to drought locally or systemically. A split‐root system was used to obtain AM plants with total or only half root system colonized as well as to induce physiological drought affecting the whole plant or non‐physiological drought affecting only the half root system. We analysed the local and/or systemic nature of the AM effects on accumulation of osmoregulatory compounds and aquaporins and on antioxidant systems. Maize plants accumulated proline both, locally in roots affected by drought and systemically when the drought affected the whole root system, being the last effect ampler in AM plants. PIPs (plasma membrane intrinsic proteins) aquaporins were also differently regulated by drought in AM and non‐AM root compartments. When the drought affected only the AM root compartment, the rise of lipid peroxidation was restricted to such compartment. On the contrary, when the drought affected the non‐AM root fraction, the rise of lipid peroxidation was similar in both root compartments. Thus, the benefits of the AM symbiosis not only rely in a lower oxidative stress in the host plant, but it also restricts locally such oxidative stress.     

盐胁迫下AM真菌对红花耐盐性的影响

在盐胁迫下,采用盆栽方法研究AM真菌对红花植株耐盐生理指标的影响,以不接种为对照。结果表明,在0、0．1％和0．2％浓度NaCl胁迫下,AM真菌促进红花幼苗的生长,接种真菌的红花叶片SOD和CAT活性、脯氨酸和可溶性蛋白的含量都高于不接种处理的,叶片细胞质膜透性和MDA含量则低于不接种处理的,结果证明AM真菌可以提高植物的耐盐性。     

盐胁迫下接种AM真菌对玉米耐盐性的影响

以玉米品种陕单16号幼苗为材料,用盆栽法研究了不同含盐量(0、0.5、1.0、1.5和2.0 NaCl g/kg)土壤接种AM真菌(Glomus mosseae)对玉米幼苗生物量、盐害级数,以及叶片中电解质透出率、丙二醛、O·2-、H2O2含量和保护酶活性的影响.结果表明:在盐胁迫下,接种AM真菌增加了玉米植株生物量,降低了玉米的盐害级数;菌根植株叶片中过氧化氢酶的活性高于非菌根植株,而过氧化物酶、抗坏血酸氧化酶和多酚氧化酶的活性则为非菌根植株高于菌根植株;超氧化物歧化酶的活性在NaCl浓度为0、0.5和1.0 g/kg时为非菌根植株高于菌根植株,而在NaCl浓度为1.5和2.0 g/kg时则为菌根植株高于非菌根植株;菌根植株叶片中电解质透出率、丙二醛、O·2-和H2O2的含量低于非菌根植株.可见,AM真菌的侵染提高了玉米的耐盐性,缓解了由盐胁迫引起的过氧化胁迫对玉米植株的伤害,但这一缓解作用并不只是通过提高保护酶活性来实现的,可能还存在一些非酶促的调节机制.     

海滨沙滩单叶蔓荆对沙埋的生理响应特征

海滨沙滩单叶蔓荆(Vitex trifolia L.var.simplicifolia)是优良的抗沙埋地被植物.以烟台海岸沙地单叶蔓荆为材料,通过不同厚度沙埋过程中沙上和沙下叶片抗逆生理指标的测定以揭示其抗沙埋生理调控机制.结果表明,轻度和中度沙埋5d,成株和幼株整株叶片细胞膜透性增大、POD和SOD活力增高、MDA和脯氨酸含量和叶片相对含水量(RWC)增加、可溶性糖含量下降.但同株沙上叶片细胞膜透性、MDA含量、SOD和POD活力和可溶性糖含量均高于沙下,而沙上叶片脯氨酸含量低于沙下叶片.在轻度和中度沙埋lOd,沙上叶片细胞膜透性、MDA和可溶性糖含量、叶片POD活力降低,叶片SOD活力仍有小幅度增高,但脯氨酸含量增加,沙上叶片生长旺盛.研究表明,沙埋下叶片抗氧化酶活力和脯氨酸含量与细胞膜透性和膜脂过氧化成正相关.沙埋使植株上部叶片接近沙表面而经受干旱和地面热辐射胁迫引起细胞膜脂过氧化加剧和细胞膜透性加大.同时沙埋也使沙下叶片遭遇黑暗和缺氧胁迫诱导细胞内膜脂过氧化,但也激活了叶片抗氧化酶保护系统和叶片脯氨酸的积累抑制细胞膜脂过氧化维护细胞膜的稳定.因此在沙埋过程中,叶片快速响应沙埋胁迫激活叶片抗氧化酶系统抑制膜脂过氧化作用维持氧自由基和抗氧化酶系统的动态平衡在单叶蔓荆适应轻度和中度沙埋,维护沙上叶片旺盛生长中起重要作用,也是重度全埋下沙下植株茎顶端能快速延伸弯曲生长最后顶出沙面再生的主要生理保护原因.