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.

Cold acclimation is an adaptive response whereby plants from temperate regions increase their capacity to tolerate freezing in response to low-nonfreezing temperatures. Numerous studies have unveiled the large transcriptome re-programming that takes place during cold acclimation in diverse species, and a number of proteins have been identified as important regulators of this adaptive response. Post-translational mechanisms regulating the function of proteins involved in cold acclimation have been, however, much less studied. Several components of the signal transduction pathways mediating cold response have been described to be post-translationally modified. These post-translational modifications, including protein phosphorylation and dephosphorylation, ubiquitination, SUMOylation, N-glycosylation and lipid modification, determine key aspects of protein function such as sub-cellular localization, stability, activity or ability to interact with other proteins. Integrating these post-translational mechanisms within the appropriate spatio-temporal context of cold acclimation is essential to develop new crops with improved cold tolerance. Here, we review available evidence regarding the post-translational regulation of cold acclimation, discuss its relevance for the accurate development of this response, and highlight significant missing data.Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

【目的】 研究水、盐、温及其交互作用等环境因子对无膜滴灌棉种中棉619萌发特性的影响。【方法】 基于正交试验、隶属函数法及聚类分析,以PEG模拟干旱胁迫、NaCl模拟土壤盐分胁迫及用生化培养箱控制环境温度,对比分析水、盐、温及其交互作用对无膜滴灌棉种中棉619(无膜棉)和膜下滴灌棉种新陆中37号2个棉种萌发特性的影响。【结果】 两者均对温度有较高的要求,而无膜滴灌棉种耐盐及抗旱性优于膜下滴灌棉种,其中温度对于种子萌发的影响达到极显著水平(P<0.01),盐分达到显著水平(P<0.05),而水分及交互作用未达到显著水平。【结论】 适宜无膜滴灌棉种中棉619环境因子范围是温度为25℃,盐分为0.1%~0.4%,水分为7.5%和15%,当水分含量为15%、盐分含量为0.2%及温度为25℃时,无膜滴灌棉种的萌发效果最好。

<b>【Objective】</b> To study the effects of water, salt, temperature and interaction on the germination characteristics of Zhongmian 619 cottond.<b>【Methods】</b> Based on orthogonal experiments, membership function method, and cluster analysis, PEG simulates drought stress, NaCl simulates soil salt stress, and a biochemical incubator were used to control the environmental temperature.The effects of water, salt, temperature and their interactions on filmless drip irrigation were compared and analyzed.After that, effects of germination characteristics on cotton cultivar Zhongmian 619 (filmless cotton) and Xinluzhong 37 cotton cultivar Xinluzhong under drip irrigation were compared.<b>【Results】</b> The results show that: Both had higher requirements for temperature, and the salt tolerance and drought resistance of cotton seeds without film and drip irrigation were better than those under drip irrigation.The effect of temperature on seed germination reached a significant level (<i>P </i>&lt;0.01), the salinity reached a significant level (<i>P </i>&lt;0.05), but the moisture and interactions did not reach a significant level.<b>【Conclusion】</b> Therefore, the suitable environmental factors for Zhongmian 619 cotton with no film drip irrigation are temperature 25℃, salt content 0.1%-0.4%, water content 7.5% and 15%, when water content is 15%, salt content is 0.2% and temperature is 25℃, the germination of the filmless cotton seed without drip irrigation was the best.

【目的】研究低温对棉花种子萌发特性的影响,筛选耐冷种质资源,探讨模糊隶属函数法在棉花种子低温耐冷性鉴定的应用。【方法】以近10年新疆北疆主栽的棉花品种(系)为试材,测试种子发芽指标对不同温度的响应变化,基于发芽指标和相对发芽指标(耐冷系数)的模糊隶属函数值法,对试材的低温萌发能力差异进行评价。【结果】随着胁迫增强,棉花种子的萌发能力受到显著抑制,种子平均发芽速度随温度上升呈下降趋势,而其它发芽指标均随温度上升呈显著增高。棉花种子的耐冷萌发力均与其萌发指标显著正相关。同一低温下两种隶属函数法对种子低温萌发能力的鉴定结果高度一致,但不同低温下参试棉花种子的萌发力有所差异。15℃种子萌发强的为中棉所36号和新陆早46号,20℃为新陆早25号、新陆早42号、新陆早36号、新陆中26号、中棉所36号、新陆早41号和新陆早35号。低温下,除了平均发芽速度,其它棉花种子的发芽指标间及其与种子萌发力两两极显著相关。采用逐步回归法建立了不同低温下棉花种子萌发耐冷性的鉴定模型,其中15℃为Y=0.01+0.022^*发芽指数,20℃为Y=-0.046+0.002^*发芽率+0.005^*种子萌发指数。【结论】萌芽期种子耐冷性强的材料为中棉所36号和新陆早46号。基于发芽指标的模糊隶属函数法可以有效用于棉花种子萌芽的耐冷性鉴定评价。

【<b>Objective</b>】 In order to understand the effect of low temperature on seed germination and to explore the suitable methods for identifying chilling tolerance of cotton seeds.【<b>Method</b>】Some mainly-cultivated cottons were selected as the experimental materials in northern Xinjiang in recent ten years, responses of seed germination characteristics to different temperature were studied, and their germination abilities were also evaluated using germination parameters and relative germination parameters (cold tolerance coefficient)according to subordinative function method under low temperature, respectively.【<b>Result</b>】With the increase of stress, the germination ability of cotton seeds was significantly inhibited, the average seed germination rate decreased with the increase of the temperature, and other indexes of germination were significantly higher with the increase of the temperature. The cold resistant germination ability of cotton seeds was positively correlated with the tested germination index. At the same low temperature, two kinds of subordinate function method showed a good agreement on the seed germination ability at low temperature, but the germination rate of cotton seed under different low temperature was different. The seed germination of Zhongmiansuo No.36 and Xinluzao No.46 had a high chilling-tolerance at 15℃, and at 25℃, those with high chilling tolerance were Xinluzao No.25, Xinluzao No.42, Xinluzao No.36, Xinluzhong No.26, Zhongmiansuo No.36, Xinluzao No.41 and Xinluzao No.35. Except for the average germination speed, the relationship among others germination parameters and seed germination ability was significantly correlated. The identification model for cold resistant cotton seed germination under low temperature was established by stepwise regression method: <i>Y=0.01+0.022^*</i> GI (germination index) (<i>R</i>²=0.998) at 15℃; <i>Y=-0.046+0.002^*</i> GR (germination rate) +0.005^* SGC (Seed germination coefficient) (<i>R</i>²=0.992) at 12℃. 【<b>Conclusion</b>】The seed of Zhongmiansuo NO.36 and Xinluzao NO.46 had a high chilling tolerance at the seed germination stage. The germination index of fuzzy membership function method can be effectively used for the identification and evaluation of cold tolerance based on cotton seed germination.

A total of 13 cucumber materials were used to study the relationships of cucumber's chilling tolerance with the 12 growth indices at germination and seedling stages. There existed significant differences in the relative germination rate, germination index, hypocotyl length, and vigor index at 17 degrees C among the 13 materials (P < 0.05), which also significantly correlated to the chilling tolerance. At seedling stage, the physiology among the materials after treated at 4 degrees C for 2 days had obvious difference. Chilling injury index had significant correlation with the survival rate after recovery, but less correlation with the soluble protein (SP) content, electric conductivity (EC), and superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) activities. The chilling tolerance of the materials was classified into three levels by clustering analysis, and the cucumber' s chilling tolerance equations at the two stages were established through stepwise regression analysis. Based on confidence interval value, the chilling tolerance of cucumber could be well assessed.

Reactive O(2) species (ROS) are produced in both unstressed and stressed cells. Plants have well-developed defence systems against ROS, involving both limiting the formation of ROS as well as instituting its removal. Under unstressed conditions, the formation and removal of O(2) are in balance. However, the defence system, when presented with increased ROS formation under stress conditions, can be overwhelmed. Within a cell, the superoxide dismutases (SODs) constitute the first line of defence against ROS. Specialization of function among the SODs may be due to a combination of the influence of subcellular location of the enzyme and upstream sequences in the genomic sequence. The commonality of elements in the upstream sequences of Fe, Mn and Cu/Zn SODs suggests a relatively recent origin for those regulatory regions. The differences in the upstream regions of the three FeSOD genes suggest differing regulatory control which is borne out in the research literature. The finding that the upstream sequences of Mn and peroxisomal Cu/Zn SODs have three common elements suggests a common regulatory pathway. The tools are available to dissect further the molecular basis for antioxidant defence responses in plant cells. SODs are clearly among the most important of those defences, when coupled with the necessary downstream events for full detoxification of ROS.