Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources
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Improvement of wheat seed vitality by dielectric barrier discharge plasma treatment
No full textInfluences of discharge voltage on wheat seed vitality were investigated in a dielectric barrier discharge (DBD) plasma system at atmospheric pressure and temperature. Six different treatments were designed, and their discharge voltages were 0.0, 9.0, 11.0, 13.0, 15.0, and 17.0kV, respectively. Fifty seeds were exposed to the DBD plasma atmosphere with an air flow rate of 1.5Lmin(-1) for 4min in each treatment, and then the DBD plasma-treated seeds were prepared for germination in several Petri dishes. Each treatment was repeated three times. Germination indexes, growth indexes, surface topography, water uptake, permeability, and -amylase activity were measured. DBD plasma treatment at appropriate energy levels had positive effects on wheat seed germination and seedling growth. The germination potential, germination index, and vigor index significantly increased by 31.4%, 13.9%, and 54.6% after DBD treatment at 11.0kV, respectively, in comparison to the control. Shoot length, root length, dry weight, and fresh weight also significantly increased after the DBD plasma treatment. The seed coat was softened and cracks were observed, systematization of the protein was strengthened, and amount of free starch grain increased after the DBD plasma treatment. Water uptake, relative electroconductivity, soluble protein, and -amylase activity of the wheat seed were also significantly improved after the DBD plasma treatment. Roles of active species and ultraviolet radiation generated in the DBD plasma process in wheat seed germination and seedling growth are proposed. Bioelectromagnetics. 39:120-131, 2018. (c) 2017 Wiley Periodicals, Inc
Abscisic acid and brassinolide combined application synergistically enhances drought tolerance and photosynthesis of tall fescue under water stress
No full textTall fescue (Festuca arundinacea Schreb.) is a widely used cool-season turfgrass, and its growth is mainly limited by water deficit. Abscisic acid (ABA) and brassinolide (BR) are two important stress hormones regulating plant physiological processes and growth under water deficit. To investigate effects of exogenous ABA and BR on physiological and photosynthetic performance of tall fescue under water stress conditions, ABA (10 and 20 mg L-1) and BR (0.4 and 0.8 mg L-1) were applied individually and in combination (0.4 mg L-1 BR and 10 mg L-1 ABA) under three soil water regimes [75 +/- 5% FC (HW), 50 +/- 5% FC (MW) and 25 +/- 5% FC (LW)] in the greenhouse. Results revealed that ABA and BR application markedly decreased the relative conductivity and malondialdehyde, notably increased leaf relative water content, antioxidant enzyme activity and proline content under water stress. ABA plus BR application was equally effective in improving the activities of antioxidant enzyme as ABA at 20 mg L-1. ABA application reduced stomatal conductance and decreased both transpiration and net photosynthetic rate (P-n), while BR application significantly increased P-n and water use efficiency (WUE) by enhancing chlorophyll content. The ABA and BR combination application showed higher P-n and WUE as well as BR single application. It indicated that ABA and BR combination application increased photosynthetic capacity, and reduced the effect on photosynthetic loss caused by ABA under water stress. All these confirmed that ABA plus BR application exhibited a synergistic interaction on enhancing drought tolerance and photosynthesis of tall fescue under water stress
Projecting the Range Shifts in Climatically Suitable Habitat for Chinese Sea Buckthorn under Climate Change Scenarios
No full textUnderstanding the impact of climate change on range shifts in climatically suitable habitats of tree species is important for national afforestation planning, which can enhance the adaptation of tree plantation to climate change through movement of tree to follow suitable climatic conditions. Here, we overlap the current and future climate-related ranges of Chinese sea buckthorn (Hippophae rhamnoides subsp. sinensis), an important tree used for afforestation in China, to estimate the range shift in three geographic dimensions (latitude, longitude and elevation) between 2000 and 2070, which are projected by the maximum entropy algorithm (MaxEnt) under current climate conditions and four climate change scenarios (RCP2.6, RCP4.5, RCP6.0, and RCP8.5). Our results show that the performance of the MaxEnt is highly accurate, with test AUC (area under the receiver operating characteristic curve) value of 0.91, Kappa value of 0.83 and predicted accuracy of 92%. About 10.7% area of land in China is climatically suitable for Chinese sea buckthorn plantation. Low representative concentration paths will have more effect on loss of climatic range and less effect on expansion of climatic range for Chinese sea buckthorn, while the impacts of high representative concentration path is the opposite. The centroids of climatic ranges will shift westward or northwestward at the rate of 10.4-22 km per decade, and the centroids of altitude will shift upward at the rate of 43-128 m per decade. The expansion area of climatically suitable habitat, covering 2.6-5.2 x 10(5) km(2), is expected to be mainly located in parts of Qinghai, Ningxia, Gansu, Sichuan, Liaoning, and Jilin provinces; these areas should be monitored for planting of Chinese sea buckthorn in the future
黄土塬区旱作农田土壤水库动态及蒸散规律
No full text本文结合长期定位试验，以长武塬区冬小麦和春玉米土壤水分动态变化研 究为基础，深入分析了旱作农田土壤水库动态及蒸散规律。同时明确了春玉米和冬小麦生长期蒸散耗水的水分来源，评估了农田生态系统的水量平衡状况，并对土壤干层的形成及恢复过程有了初步的认识，为提高了相关知识的实践运用旱作农业的生产实践和可持续发展提供数据支撑和理论依据。主要研究结论如下：
（1）冬小麦田间年均土壤含水量垂直分布曲线均呈“双峰双谷”形，第一处峰点在10～20 cm土层，第一处谷点在50 cm左右，第二处峰点在100 cm左右，第二处谷点在280 cm左右。无论何种降水年型下，土壤水库对降水的响应滞后且滞后的程度一致。降水年型对土壤水库的年际与年内动态变化影响较大。与丰水年相比，枯水年、平水年土壤水库对大气干旱的调节能力降低，表现为主要供水层上移；枯水年、平水年降水量虽少，但对土壤水分的补充作用较丰水年明显；丰水年土壤水库有较大盈余（84.2 mm），水分平衡出现正补偿，枯水年土壤水库稍有亏缺（1.5 mm），水分平衡出现负补偿，平水年土壤水库稍有盈余（9.5 mm），水分平衡出现正补偿.长武旱塬冬小麦田间土壤水分动态可分为4个时期：苗期耗水期、缓慢消耗期、大量消耗期、收获期，整体蒸散耗水大小顺序为：大量消耗期>苗期耗水期>收获期>缓慢消耗期。
（2）春玉米田间年均土壤含水量垂直分布曲线均呈“单峰单谷”形，峰点在10～20 cm层，谷点在50 cm左右，70～100 cm层土壤含水量常年较稳定。与丰水年相比，枯水年春玉米生长期田间土壤水库对大气干旱的调节能力降低，表现为主要调节深度上移变浅；枯水年春玉米生长期田间土壤水分比丰水年稳定。两种降水年型下土壤水库“水位”均呈现先上升后下降再上升的特点。枯水年土壤水库有较大亏缺，第2季亏缺为94.3 mm，第4季为123.7 mm，水分平衡均出现负补偿；丰水年土壤水库有较大盈余（208.6 mm），水分平衡出现正补偿。春玉米和冬小麦生长期蒸散耗水的水分来源不同，对于冬小麦，一部分是生长期降水，另一部分是休闲期降水，即休闲期土壤储水；对于春玉米，丰水年时，只有生长期降水，枯水年时，一部分是生长期降水，另一部分是上一季土壤储水。
（3）运用农田水量平衡有效划分了生长期作物蒸散耗水和休闲期无效蒸散，冬小麦生长季多年蒸散均值约为540.8 mm，其中，休闲期无效蒸散均值约为103.2 mm，占年蒸散的19.1%；春玉米生长期多年蒸散均值为547.0 mm，休闲期无效蒸散均值为136.8 mm，占比25.0%。长武塬区冬小麦和春玉米蒸散水平相当，休闲期无效蒸散均较高。冬小麦生长季蒸散呈较明显的双峰曲线分布，春玉米生长季蒸散呈较明显的单峰曲线分布。该区冬小麦土壤能保持良好的水分生态环境，比春玉米更适合长武旱塬区发展旱地农业。
（4）降水年型是冬小麦地土壤干层形成的主导因素，年内降水分布不均是春玉米地土壤干层形成的主导因素。长武旱塬区冬小麦和春玉米一年一季的种植制度不会导致永久性干层的产生。冬小麦土壤水库充放水过程呈现收获期、休闲期与苗期连续充水和缓慢消耗期与大量消耗期连续失水相互交替的特点。0~300 cm土层和300~600 cm土层土壤水库不一致性现象明显，若以最大根深作为野外监测试验中土壤含水量的取样深度，由于深层土壤水库负反馈作用，不同降水年型下，休闲期与苗期蒸散均会被高估，缓慢消耗期与大量消耗期蒸散均会被低估。冬小麦田间过渡层存在，范围约为140~360 cm。作物生长的时间跨度影响土壤水库效应的发挥，土壤水库对冬小麦供水表现为年际间的调节作用，土壤水库对春玉米供水表现为季节间的调节作用。<br /
延安市土地利用变化及其土壤保持功能效应研究——基于InVEST模型的应用
No full text 区域的土壤侵蚀状况和生态系统的土壤保持功能不仅与降雨强度、土壤性质、地形条件等自然因素密切相关，还受人为活动等因素的影响。对于延安市来说，大规模退耕还林工程的实施显著影响了当地的土地利用状况及植被覆盖条件，从而引起了区域土壤侵蚀量及保持量的改变。本文分析了延安市十五年来的土地利用变化，并在此基础上，采用InVEST模型即生态系统服务功能与权衡交易综合评价模型中的“泥沙输移比”模块，对延安市退耕还林前后2000年和2015年的土壤侵蚀量、土壤保持服务功能及其价值进行了评估，并探讨了土地利用变化对土壤侵蚀及土壤保持服务功能的影响。得出结论如下：
（1）2000~2015年，延安市的土地利用类型均以林地、草地和耕地为主，三者占全市面积的90%以上。十五年间各土地利用类型均发生了显著变化，其中林地的面积增幅最大，耕地面积大幅减少。林地主要分布于10°以上的缓坡和陡坡地上，15年来林地面积在各坡段上均有增加且在大于25°的陡坡地上增加最为显著；草地在各坡段上的分布及变化与林地较为一致；耕地各坡段面积均是减少的，且在大于25°的陡坡上几乎全部退耕；城镇用地大多分布于15°以下，15年来各坡段面积比例变化不大，但各坡段面积均处于增加状态；水域面积集中分布在10°以下坡段，且各坡段上面积均有增加。15年间延安市各地类之间转换较为频繁，退耕还林工作主要经历退耕还草、退耕还林、草地逐渐转为林地的循序渐进过程。
（2）延安市2000年及2015年的土壤侵蚀总量分别为220.06106t， 138.37106t。其土壤侵蚀强度的空间分布特征较为明显，微度侵蚀和轻度侵蚀主要集中分布在延安市南部的低山丘陵区及黄土沟间地貌区，强度、极强度和剧烈侵蚀主要分布在东北和西北部的黄土丘陵沟壑区。延安市土壤侵蚀强度随着坡度的增大而呈增强的趋势，但十五年间强度、极强度和剧烈侵蚀在各坡段上的面积均有不同程度的减少且面积向较陡的坡段集中，说明了治理土壤侵蚀的关键和难点主要在大于25°的陡坡上。延安市15年间共有18792.22km2的不同土壤侵蚀类型面积发生了转换，占区域面积的51.21%。整体来看，15年间各侵蚀强度类型均有向低等级侵蚀强度类型转换的趋势。耕地面积的减少对强度、极强度、剧烈侵蚀面积的减少占主导作用，而林地、草地面积的增加是区域内微度侵蚀和轻度侵蚀面积增加的主要因素，草地面积的变化也对区域内中度侵蚀面积增加起主导作用。
（3）延安市2000年和2015年的土壤保持总量为771.60×106t和849.33×106t，各子流域的土壤保持强度集中分布在100t/hm2 ~ 200t/hm2和200t/hm2 ~ 300t/hm2之间，二者之和占80%左右，此外，十五年间土壤保持量较高等级（＞200 t/hm2）的面积均有不同程度增加。延安市的土壤保持功能分布总体呈现由东北向西南增加的趋势，较高值出现在西南土壤侵蚀强度较低的区域和西北土壤侵蚀较高的区域。延安市的土壤保持量及单位面积土壤保持量均随着坡度的增加而增加。2000年和2015年的土壤保持功能价值分别为861.63亿元和940.45亿元，各区县的单位面积土壤保持功能价值均值为2.43元/平方米，各地类中林地、草地的单位面积土壤保持价值最大，均值分别为2.73元/平方米、2.43元/平方米。各地类的单位面积土壤保持量均为林地>草地>耕地>水域>城镇>裸地，且15年来各地类的土壤保持模数均有不同程度的增加，林地和草地的土壤保持效果最佳，均在200t/hm2以上。在土地利用类型发生变化的区域，草地向林地、耕地的转移，以及耕地向林地、草地的转移是区域土壤保持功能增加的主要动力和因素。<br /
Overexpression of SmbHLH148 induced biosynthesis of tanshinones as well as phenolic acids in Salvia miltiorrhiza hairy roots
No full textPhenolic acids and tanshinones are the two important groups of pharmaceutical ingredients presented in Salvia miltiorrhiza Bunge. The bHLH transcription factors could regulate secondary metabolism efficiently in plants. However, there are only some MYCs have been studied on regulation of either phenolic acids or tanshinones biosynthesis. In this study, a bHLH TF named SmbHLH148, which is homologous to AtbHLH148, AtbHLH147 and CubHLH1, was isolated and functionally characterized from S. miltiorrhiza. Transcription of SmbHLH148 could be intensely induced by ABA and also be moderately induced by MeJA and GA. SmbHLH148 is present in all the six tissues and mostly expressed in fibrous root and flowers. Subcellular localization analysis found that SmbHLH148 was localized in the nucleus. Overexpression of SmbHLH148 significantly increased not only three phenolic acids components accumulation but also three tanshinones content. Content of caffeic acid, rosmarinic acid and salvianolic acid B were reached to 2.87-, 4.00- and 5.99-fold of the control in the ObHLH148-3, respectively. Content of dihydrotanshinone I, cryptotanshinone, and tanshinone I were also present highest in ObHLH148-3, reached 2.5-, 5.04- and 3.97-fold of the control, respectively. Expression analysis of pathway genes of phenolic acids and tanshinones in transgenic lines showed that most of them were obviously upregulated. Moreover, transcription of AREB and JAZs were also induced in SmbHLH148 overexpression lines. These results suggested that SmbHLH148 might be taken part in ABA and MeJA signaling and activated almost the whole biosynthetic pathways of phenolic acids and tanshinones, thus the production of phenolic acids and tanshinones were upregulated.</p
生物炭对不同水氮条件下小麦产量的影响
No full text研究生物炭与氮肥互作在不同水分条件下对小麦关键生育期旗叶光合参数、产量与主要农艺性状的影响，探讨生物炭改良不同水肥条件土壤并提高其作物产量的效果与内在机理，可为农田有机物资源合理利用提供理论支撑。本研究采用盆栽试验，生物炭用量设置五个水平( 0，1% ，2% ，4% 和 6% ) ，氮肥设置 N0，N1 和 N2( 0，0． 2 g·kg － 1 和 0． 4 g·kg － 1 ) 三个水平，小麦拔节期控制土壤田间持水量的 80% 和 50% 模拟正常水分和干旱胁迫两种水分环境。于小麦拔节期和抽穗期测定旗叶光合参数和 SPAD 值，成熟后对小麦籽粒产量及主要农艺性状进行统计。结果显示: ( 1) 与不施生物炭处理相比，1% 和 2% 生物炭用量平均增产 6． 62% 和 11． 01% ，4% 和 6% 生物
炭用量平均减产 6． 88% 和 10． 1% ，同时会导致千粒重、穗粒数和株高的降低; ( 2) 正常水分条件下，1% 和 2% 生物炭用量与 N1 和 N2 之间存在协同增产作用，而 4% 和 6% 生物炭用量表现出负面效应; ( 3) 干旱胁迫条件下，仅 1%和 2% 生物炭用量与 N1 存在协同增产作用，生物炭处理削弱 N2 增产潜力; ( 4) N0 水平下，生物炭处理均表现出促进小麦旗叶光合速率，增加产量的作用; ( 5) N1 条件下，生物炭促进小麦旗叶光合速率且在干旱胁迫条件下效果更明显。总体上生物炭对小麦旗叶光合参数和产量的影响受生物炭用量、氮素水平和水分条件共同制约且存在复杂的交互作用，干旱会限制生物炭与氮肥的协同增产作用; 在低肥力土壤上应用生物炭的增产效果较好，而在质地较细且肥力中等的土壤应用时推荐 48 t·hm － 2 ( 2% ) 生物炭用量。</p
人工油松林中不同植物叶片非结构性 碳水化合物含量对氮添加的响应
No full text 全球氮沉降通过影响树木叶片的生理过程影响森林生态系统的结构与组成，但目前关于氮沉降对森林生态系统中不同植物叶片非结构性碳水化合物(NSC)含量的影响还不十分清楚．本研究选取黄土丘陵区人工油松林中油松、辽东栎、忍冬、绣线菊、黄刺玫、茜草、披针苔草 7 种主要高等植物，比较了 3 年氮添加(0、3、6、9 g N·m－2·a－1，分别用 N0 、N3 、N6 、N9 表示)对 7 种植物叶片中 NSC 的影响．结果表明: 不同植物叶片可溶性糖、淀粉含量变异很大，二者变异最高的均为黄刺玫，最低的分别为绣线菊和披针苔草;不同植物可溶性糖、淀粉对氮添加的响应存在明显差异．N6 处理下茜草的可溶性糖和淀粉的变异高于其他物种，N3 和 N9 处理下绣线菊的变异高于其他物种，可溶性糖和淀粉含量变异最小的物种在不同氮添加水平下不同．随着氮添加水平的增加，油松和披针苔草的可溶性糖含量持续升高，绣线菊持续降低，辽东栎、忍冬和黄刺玫的可溶性糖含量先降低后增加，在 N6 处理达到最小，而茜草的可溶性糖含量呈现较复杂的变化趋势．氮添加对植物叶片中淀粉含量的影响表现为油松、忍冬和披针苔草的淀粉含量持续增加，绣线菊先降低后增加，在 N3 处理达到最小，而黄刺玫和茜草则呈现较复杂的变化趋势，辽东栎淀粉含量变化趋势平缓．在氮添加后，土壤 pH、有机碳、全氮、全磷与植物叶片 NSC 含量无相关关系，仅 N0 和 N3 水平下上述土壤理化指标会显著影响可溶性糖/淀粉．表明林地不同植物叶片中NSC 含量对氮添加的响应明显不同，研究全球氮沉降或氮添加对林地生态系统的影响需要考虑不同植物，尤其不同生活型植物的不同响应．</p