Growth photosynthetic activity and antioxidant responses of mycorrhizal and non-mycorrhizal bajra (Pennisetum glaucum) crop under salinity stress condition

Arbuscular mycorrhizal (AM) fungi alleviating the adverse salt effects on growth was tested in bajra (Pennisetum glaucum). Towards this objective we analyzed the photosynthetic activity, proline, phosphatase activity and various antioxidant enzymes such as peroxidase, catalase and superoxide dismutase at 0, 100, 200 and 300 mM salinity levels in AM inoculated and non inoculated bajra plants. Total chlorophyll content was significantly higher in moderate salinity condition in AM fungus (Glomus fasciculatum) inoculated plants, which lead to increase in growth and nutrient uptake capacity of mycorrhizal plants. Antioxidant activity was either increased or decreased due to responses to different salinity stress conditions. Proline accumulation was induced by salt and it was more in shoot of non-AM inoculated plants, but in roots proline accumulation was higher in AM plants at all levels of salinity. This work suggests that the AM fungus helps bajra plants to perform better under moderate salinity levels by enhancing the antioxidant activity and proline accumulation as compared to non-mycorrhizal plants.     

不同维生素浸种对玉米种子萌发的影响

以玉米杂交种郑单958为试验材料,采用不同质量浓度50、100、200 mg/L的水溶性维生素V_(B1)、V_(B2)、V_(B6)、V_(B12)、V_C、V_H、V_(PP)浸种24 h,处理后分析玉米种子萌发及胚芽和根生长中脯氨酸等可溶性调节物质情况。结果表明,供试维生素在100、200 mg/L处理下基本都呈现对种子萌发指数的促进,其中,100 mg/L维生素处理对种子萌发率促进效果显著;200 mg/L维生素处理对种子发芽势显著促进作用;50 mg/L维生素对上述3个指标的影响不同。与未处理对照相比,不同种类维生素和不同质量浓度的同一维生素对根冠比影响不同。维生素浸种均可引起玉米胚芽可溶性糖含量显著升高,外源维生素浸种处理可显著影响玉米种子萌发和胚芽及胚根的生长,且不同维生素在不同浓度下对各生长指标影响及脯氨酸等可溶性调节物质变化不尽相同,对种子萌发呈显著促进作用的V_(B2)和V_(B12)在玉米种子萌发中应用前景较好。     

3种不同耐寒番茄品系的生理特性研究

[目的]研究自然条件下选育的3种不同耐寒番茄品系的耐寒指标及其生理特性。[方法]以苗龄21～28 d的番茄幼苗为材料,通过实验室冷处理模拟外界环境条件,鉴定植株的存活及生长状况;研究植株离体叶片冷处理恢复后的形态变化并测定相对电导率,鉴定不同品系番茄植株的耐寒程度,分析电导率与存活率的相关性;测定冷胁迫条件下番茄植株体内可溶性糖和脯氨酸含量变化。[结果]不同品系的番茄冷处理后,叶片形态变化、电导率大小、恢复后的生长状况存在较大差异;不同品系番茄植株体内可溶性糖含量变化差异显著,脯氨酸含量变化差异不显著。[结论]冷处理条件下不同品系番茄叶片的电导率与存活率存在一定相关性,植株耐寒性与可溶性糖含量的积累有关。     

甘露醇、过氧化氢和氯化钠处理对黑豆苗期抗旱性的影响

将黑豆幼苗用甘露醇处理后,观察其形态特性与生长状况;用过氧化氢、氯化钠分别浸泡黑豆种子,测定幼苗叶片脯氨酸含量,研究不同处理对黑豆抗旱性的影响。结果表明:甘露醇处理造成黑豆幼苗水分胁迫,致使植株较低,株型紧凑,叶直立,叶面积小,叶片薄,叶色淡绿,根毛较长,根系发达并导致叶片水势降低,幼苗的抗旱能力增强;过氧化氢处理使幼苗叶片脯氨酸含量明显下降,幼苗的抗旱性减弱;而氯化钠处理造成幼苗叶片脯氨酸含量显著提高,抗旱性增强。     

植物耐盐生理生化特性的研究进展

本文综述了盐胁迫对植物种子发芽及幼苗生长,植物主要生化指标(脯氨酸、叶绿素、可溶性糖)及细胞膜透性影响的研究,为揭示植物耐盐机理以及开展耐盐植物新品种选育提供参考依据。     

10℃低温对西瓜幼苗耐性生理指标的影响

以4叶1心期西瓜幼苗为材料,研究了10℃低温处理下3种西瓜幼苗早佳8424(冷敏感型)、万福来(中等)和野西瓜(耐冷型)的电导率、脯氨酸、可溶性糖、POD和SOD的变化规律。结果表明:西瓜幼苗的电导百分率、POD、脯氨酸随处理时间的延长而增加;SOD的活性在耐性品种中增加,敏感品种先增后降;可溶性糖含量在耐性品种呈先降后升,其它品种呈增加的趋势。根据上述生理指标的分析,我们初步研究耐冷性与冷敏感品种的生理差异。     

披碱草属野生种质资源苗期耐盐性评价及相关生理机制研究

【目的】对披碱草属野生种质资源进行苗期耐盐性评价,并对其生理机制进行初步研究,用以发掘和利用具有优良耐盐性状的披碱草野生种质资源,并为利用生理生化指标进行苗期快速准确鉴定提供依据。【方法】设置对照（0）、0.4%、0.6%、0.8%和1.0%等5个土壤盐浓度水平,对披碱草属20份野生种质材料的苗期生长参数进行测定,在此基础上采用极差分类进行种质材料的耐盐性排序。测定不同盐浓度胁迫下的游离脯氨酸含量和细胞膜透性,以及抗坏血酸过氧化物酶（APX）和超氧化物歧化酶（SOD）的活性的变化。【结果】随着盐浓度的增加,各供试材料的株高、分蘖、存活率及植株干重均呈现下降趋势,但不同材料对盐胁迫的响应有较大差异。随着盐浓度的升高,参试材料叶组织中游离脯氨酸含量呈上升趋势,在0.8%和1.0%盐浓度胁迫下,耐盐材料G5和G13的相对游离脯氨酸含量显著高于其它材料（P＜0.05）;而相对细胞膜透性显著低于其它材料（P＜0.05）;APX和SOD酶的活性也随着盐浓度的升高而升高,在0.8%和1.0%盐浓度胁迫下,耐盐材料G5、G13叶组织中APX和SOD的活性显著高于其它材料（P＜0.05）。【结论】20份野生披碱草种质材料在耐盐性上存在较大差异,耐盐性强的披碱草可作为耐盐性种质资源加以利用。植株苗期的游离脯氨酸、细胞膜透性、APX酶和SOD酶活性对盐胁迫浓度的变化响应灵敏,且在耐盐性不同的材料中变化差异显著,可以作为快速鉴定披碱草野生种质材料耐盐性的生理生化指标。     

甜瓜幼苗对NaCl胁迫伤害的生理响应

[目的]对NaCl胁迫下甜瓜幼苗生理的研究有助于探明甜瓜的耐盐机理,从而为甜瓜耐盐新品种选育和设施栽培提供依据。[方法]采用营养液水培法,研究不同浓度NaCl胁迫对甜瓜幼苗质膜相对透性、MDA、脯氨酸、光合色素含量、抗氧化物活性及POD同工酶的影响。[结果]NaCl胁迫下甜瓜幼苗叶片质膜相对透性和MDA含量较对照显著升高;且随着NaCl浓度的增加而增加。低浓度NaCI处理后．叶片脯氨酸、叶绿素含量、抗氧化活性、POD同工酶较对照有所上升,高浓度NaCl胁迫下较对照显著下降。[结论]低浓度NaCl处理有利于加强甜瓜的代谢,高浓度NaCl胁迫严重破坏了甜瓜幼苗细胞膜结构,降低了抗氧化活性,影响了脯氨酸和光合色素的正常代谢。     

An effective in-vitro acclimatization using uniconazole treatments and ex-vitro adaptation of Phalaenopsis orchid

The in-vitro acclimatization of Phalaenopsis plantlets under photoautotrophic conditions, with 0 (control), 3.43, 6.86 and 13.72 μM uniconazole (UCZ) treatments for 30 days was investigated before the plantlets were transferred to ex-vitro environments for 14 days. The physiological and growth characters of in-vitro acclimatized, and ex-vitro adapted plantlets were measured. Chlorophyll a (Chl_a), chlorophyll b (Chl_b), total chlorophyll (TC) and total carotenoid (C_x+c) content in plantlets treated with 6.86 μM UCZ were maintained at higher levels than those in plantlets of the control, by 1.82, 1.85, 1.83 and 1.93 times, respectively, leading to enrichment of the pigments in ex-vitro conditions. The maximum quantum yield of PSII (F_v/F_m), photon yield of PSII (Φ_PSII), photochemical quenching (qP) and non-photochemical quenching (NPQ) in UCZ treated plantlets and in ex-vitro adaptation were not significantly different. Proline was accumulated in the control plantlets in both in-vitro acclimatization and ex-vitro conditions, while proline in those plantlets with UCZ treatments was maintained at a low level, which was defined by unstressed conditions. Net photosynthetic rate (P_n) in 6.86 μM UNZ treated plantlets peaked at a higher level than that of the control plantlets, both in-vitro and ex-vitro, by 3.27 and 2.93 times, respectively. In addition, proline content and P_n were inversely related in both in-vitro acclimatization and ex-vitro adaptation. The P_n in UCZ acclimatized plantlets was negatively correlated with plant dry-weight. In-vitro photoautotrophic Phalaenopsis plantlets were successfully acclimatized using a 6.86 μM UCZ treatment which caused them to adapt quickly to ex-vitro environments.     

香稻PRO基因的克隆及表达载体的构建

利用逆转录一聚合酶链式反应(RT-PCR)得到在水稻中特异性表达的脯氨酸氧化酶(PRO)基因.DNA序列分析表明,所获得水稻的PRO cDNA的最大开放阅读框序列全长为1 428 bp,可编码476个氨基酸.该序列与NCBI网站上已发表的PRO基因100%相似.为了能进一步验证所克隆的序列是我们所需的目的基因,成功构建了PRO基因超表达载体和PRO基因干涉载体,便于导入水稻中进行基因的功能鉴定.