不同促根措施对皖南烤烟成熟期钾素代谢的影响

以大田正常施肥为对照（CK）,设置增施黄腐酸钾（TPFA）、γ-聚谷氨酸（TPGA）和豆浆灌根（TSRI）3个处理,研究不同促根措施对烤烟成熟期根系生理、烤后烟叶钾含量、烟株不同部位钾积累量、钾离子通道基因（NKT1、NtKC1、NtORK1、NtTPK1）和转运体基因（NtHAK1、NtKT12）表达量的影响。结果表明,处理的根鲜重、干重和体积均显著高于CK处理,TPFA和TSRI处理的根系活力显著高于TPGA处理;TSRI和TPGA处理可明显提高烤后烟叶的钾含量;不同促根措施可显著促进根、茎和中部叶的钾积累量;TSRI处理的根中NtORK1的相对表达量显著低于CK处理,TPGA和TPFA处理的上部叶和中部叶NtORK1的相对表达量极显著低于CK处理;TSRI处理根中NtTPK1的相对表达量极显著高于其他处理;3个处理根中NtHAK1的表达量极显著高于CK处理。综合来看,TPGA和TSRI处理不但能促进根系发育、提高钾积累量,而且成熟期烟株对钾的吸收和转运能力强,增加烤后烟叶的钾含量。     

典型喀斯特山地城市镶嵌山体斑块格局时空变化特征

喀斯特山地城市镶嵌山体对生物多样性保护、生态系统健康稳定、生态系统服务具有重要的作用和功能。为探明喀斯特山地城市镶嵌山体斑块的时空变化,以典型喀斯特山地城市贵阳市中心城区为对象,运用2000—2020年5期高分辨率遥感影像,采用GIS空间分析、探索性空间数据模型、景观格局分析等方法,从规模、形态和空间分布方面,分析了快速城市化背景下山体斑块格局的时空变化特征。结果表明:(1)贵阳市中心城区山体斑块数量和面积分布广泛,但20年间山体斑块数量减少30座,面积减幅达25.2%,表现出先切割打碎后吞并侵占的特征,其中大型山体规模持续减小,其他各类型山体数量和面积呈“先增后减”的变化趋势。(2)山体斑块分维数接近1,整体形状较为规则,2000—2020年山体斑块形状指数增大近1.12倍,斑块形状总体呈现复杂化、破碎化的趋势; 但大型、中大型山体斑块形状更加规则化,而其他类型山体斑块形状日趋复杂破碎。(3)山体斑块具有极显著的空间聚集效应,最邻近指数介于0.766 9～0.841 4,全局性空间聚类标准化Z值小于-2.58,以小面积山体斑块的聚集为主,分布具有明显的空间异质性。20年间,空间聚集效应减弱,高密度区逐渐萎缩,低密度区不断扩散且呈集中连片趋势; 并且山体斑块的潜在生态连通性水平持续降低。     

黄河中游窟野河流域水沙关系变化特征及其成因分析

为探讨人类活动和气候变化对窟野河流域水沙情势的影响,基于1956—2019年窟野河流域降水量、径流量和输沙量等监测数据,运用累积距平法、双累积曲线等方法对窟野河流域水沙变化的特征及其成因进行了分析。结果表明:窟野河流域降水量随时间变化呈不明显减小趋势,而径流量和输沙量随时间变化却呈显著减小趋势,流域水沙减少的因素不是气候变化引起的降水因素; 径流量和输沙量年际变化的转折年份为1979年和1997年; 同基准期A(1956—1979年)相比,B时期(1980—1997年)气候变化对径流量和输沙量的贡献率分别为14.25%,14.22%,人类活动对径流量和输沙量的贡献率分别为85.75%,85.78%,C时期(1998—2019年)气候变化对径流量和输沙量的贡献率分别为8.76%,6.65%,人类活动对径流量和输沙量的贡献率分别为91.24%,93.35%,降水变化和人类活动都是造成窟野河流域水沙减少的影响因素,其中流域内逐年增强的人类活动是窟野河流域径流和输沙减少的主要因素,而气候变化引起的降水减少是次要因素。     

近15年来青海湖流域气温、降水变化对植被物候驱动分析

研究气候变化对植被物候的驱动分析,对于深入理解高寒植被适应全球气候变化具有重要意义。选取MCD12Q2植被物候数据,利用相关分析和GIS空间分析,对近15年来青海湖流域气温、降水变化与植被物候关系进行了研究。结果表明:近15年来青海湖流域植被返青期(start of growing season,SOS)、植被生长期长度(Length of growing season,LOS)、休眠期(Dormancy of growing season,DOS)与年均气温呈显著相关关系,其偏相关系数分别为-0.57～0.36,-0.89～0.81和-0.29～0.51; 与年均降水量偏相关系数分别为-0.58～0.38,-0.82～0.93和-0.23～0.23,表明流域植被SOS和LOS变化主要受年均气温和降水量共同影响,DOS变化主要受年均气温影响。青海湖流域植被SOS,LOS和DOS在空间上受气温、降水及其共同驱动的区域占比分别为33.7%,22.5%和36.67%,其受非气温—降水驱动的区域占比分别为66.3%,77.5%和63.33%; 沿海拔梯度方向上(海拔每上升100 m),年均气温上升1℃,植被SOS提前0.35 d,植被LOS延长0.15 d,植被DOS推迟0.25 d; 年均降水量增加1 mm,植被SOS推迟4 d,植被LOS缩短1.69 d; 植被DOS提前2.85 d。可见,近15年气温、降水变化对青海湖流域植被物候的驱动在空间上存在差异性,空间上植被物候主要受非气温—降水影响,海拔梯度上植被物候受气温和降水影响显著。     

Effect of topography on the changes of Urumqi Glacier No. 1 in the Chinese Tianshan Mountains

Topography plays an important role in determining the glacier changes. However, topography has often been oversimplified in the studies of the glacier changes. No systematic studies have been conducted to evaluate the relationship between the glacier changes and topographic features. The present study provided a detailed insight into the changes in the two branches (east branch and west branch) of Urumqi Glacier No. 1 in the Chinese Tianshan Mountains since 1993 and systematically discussed the effect of topography on the glacier parameters. This study analyzed comprehensive recently observed data (from 1992/1993 to 2018/2019), including mass balance, ice thickness, surface elevation, ice velocity, terminus, and area, and then determined the differences in the changes of the two branches and explored the effect of topography on the glacier changes. We also applied a topographic solar radiation model to analyze the influence of topography on the incoming shortwave radiation (SW_in) across the entire glacier, focusing on the difference in the SW_in between the two branches. The glacier mass balance of the east branch was more negative than that of the west branch from 1992/1993 to 2018/2019, and this was mainly attributed to the lower average altitude of the east branch. Compared with the west branch, the decrease rate of the ice velocity was lower in the east branch owing to its relatively increased slope. The narrow shape of the west branch and its southeast aspect in the earlier period resulted in a larger glacier terminus retreat of the west branch. The spatial variability of the SW_in across the glacier surface became much larger as altitude increased. The SW_in received by the east branch was slightly larger than that received by the west branch, and the northern aspect could receive more SW_in, leading to glacier melting. In the future, the difference of the glacier changes between the two branches will continue to exist due to their topographic differences. This work is fundamental to understanding how topographic features affect the glacier changes, and provides information for building different types of relationship between the glacier area and ice volume to promote further studies on the basin-scale glacier classification.     

慢性镉暴露对小鼠血常规的影响

本试验探究了慢性镉暴露对小鼠血常规的影响。结果表明,与正常小鼠比较,镉中、高剂量组淋巴细胞值增高,中剂量组增高具有统计学意义(P0.05);高剂量组红细胞体积分布宽度与红细胞平均体积较正常组显著性降低(P0.05);高剂量镉暴露降低了血小板计数、血小板比容。因此,在长期低浓度镉暴露下,红细胞比容和淋巴细胞计数可有潜力成为镉毒性的早期预警指标,外周血淋巴细胞比其他血液指标更敏感。     

芝麻吸钾特点与施用钾肥技术的研究

１９８６～１９８９年在河南省芝麻主要产区布置了田间试验。结果表明，每生产１００ｋｇ芝麻种子需要钾素（Ｋ２Ｏ）６．２４～６．６８ｋｇ。不同生育阶段吸收钾素的比例相差很大，钾肥的增产效果也因年份不同而异。缺钾土壤，其速效钾含量低于１２μｇｇ－１，每公顷施用Ｋ２Ｏ１０５～１２０ｋｇ作基肥，可获得最大增产效益。     

锌和钾对甜菜生长中后期干物质积累的影响

单独施用锌肥和钾肥对提高甜菜生长中后期块根干物质积累的作用差异不明显，其效果低于这两种肥料共同施用。单独施锌有利于提高群体的叶面积指数，并具有延缓叶片衰老的功效，对提高块根含糖作用也较明显。单独施钾时，可以使生长中心转移提前。当两种肥料一同施用时，增加钾肥用量即可提高块根干物质，又可提高块根含糖量，而增加锌的用量效果不明显。     

氯化钾中的钾素和氯素对玉米茎腐病防治效果研究

通过长期定位试验和田间试验,研究了缺钾条件下钾素、氯素以及氯化钾对玉米不同抗性品种茎腐病的防治效果,明确钾素和氯素在氯化钾防治玉米茎腐病中的作用。结果表明,施钾可明显增强抗、感病品种抗茎腐病的能力,且对感病品种的防治效果优于抗病品种;施氯对抗、感病品种茎腐病防治效果均不明显。施钾明显增加了吉单180(抗病品种)、吉单327(感病品种)根、茎、叶部的钾素含量,在缺钾条件下,抗病品种较感病品种具有更强的吸钾能力。分析发现,蜡熟期的根部钾素含量与玉米茎腐病的发生率相关最密切,相关系数r=-0.9218。土壤养分是决定氯化钾中钾素还是氯素发挥主导作用的关键因素。     

Comparative effects of mono and dipotassium phosphates on cell leakiness in corn leaves

The quantity of nutrients which can be sprayed onto the foliage of plants is limited by the onset of burn damage, but the mechanism(s) of burn induction are not defined. Droplets of KH₂PO₄ applied to intact leaf cuticles induced burn damage at concentrations ≥ 0.50 M whereas K₂HPO₄ was damaging at 0.05 M. Different cuticular penetration rates did not account for these differences. We report here on the comparative effects of these two salts on membrane integrity, as expressed by leakage of U.V. absorbing constituents from leaf cells. Infiltration of a hypotonic solution (0.05 to 0.10 M) of either salt into corn leaf segments did not induce selective acceleration of leakage of U.V. absorbing constituents from leaf cells during a 90 min. incubation. However, incubation in 0.10 M K₂HPO₄ lead to a 87% increase in the efflux of cell constituents when followed by a 10 min. osmotic stress treatment in 1M sucrose and subsequent transfer to water.

The induction of damage by K₂HPO₄ applied to intact plants was inhibited by high humidity low stress conditions. The results suggest that K₂HPO₄ has a selective toxic effect on plant cells which is potentiated by environmental water stress.