水稻幼苗根系吸收NO3-对细胞膜电位的影响

利用玻璃微电极技术测定了扬稻6号(籼稻)幼苗根尖细胞在吸收不同NO3-浓度(0.01、0.02、0.1、0.2、0.5、1.0和2.0.mmol/L)过程中膜电位的变化。结果表明,1)水稻根系吸收NO3-引起膜的去极化,去极化到一定程度后出现复极化;有小部分水稻根表现为超极化。在0.01～1.0.mmol/L范围内,去极化大小随外界NO3-浓度的增加而增加,且差异显著(P0.05)。0.01.mmol/L.NO3-产生较小的去极化,平均为3.8.mV;0.5.mmol/L.NO3-产生了最大去极化,平均为40.2.mV;当外界NO3-浓度大于1.0.mmol/L时膜电位去极化大小呈下降趋势。根系吸收不同浓度的NO3-而使膜电位去极化的进程符合Michaelis-Menten动力学。2)复极化有部分复极化和完全复极化两种。超极化也有两种:一种是膜电位先超极化,后缓慢复极化;另一种是先出现一个小的去极化,然后是较大幅度的超极化。3)运输蛋白抑制剂PGO抑制了根系吸收NO3-而产生的膜电位的响应。4)对于经CaSO4溶液预培养的水稻来说,C2+主要引起膜电位超极化。     

"3S"技术及其在退耕还林中的应用

退耕还林是国家为保护生态环境、治理水土流失的一项重大举措,但在广大的基层农村,还缺乏有效的技术支持手段。“3S”技术是集遥感、全球定位与地理信息系统于一体的高新技术手段,可以为退耕还林提供强有力的技术支持。就“3S”技术在梅州市退耕还林应用中的设备选用、技术路线、基本过程与方法等进行了探讨,对基层退耕还林工作的开展起到一定的指导作用。     

Competition between 2x and x pollen in styles of Solanum tuberosum determined by a quick in vivo method

Summary Pollen competition in vivo was studied by placing two pollen samples on one stigma and comparing the length of the tubes under a U.V. microscope. Comparisons involving pollen of Solanum tuberosum and S. phureja showed that 2x pollen grew faster than x pollen, both in 2x and x styles. Consequences for induction of dihaploids in S. tuberosum are discussed.     

基于GWR模型降尺度模拟蒙古高原地区TRMM降水数据

以多年月平均NDVI值高于0.1为阈值,对蒙古高原进行“植被区”与“非植被区”的子区域划分。在分析“植被区”植被对降水响应时滞性和“非植被区”陆地表面温度不同数据值与降水量相关性的基础上,子区域分别构建了TRMM3B43降水数据与海拔、坡度、坡向数据、归一化植被指数（NDVI）/陆地表面温度（LST）数据的地理加权回归（GWR）模型,得到区内2006-2015年每年5-10月1km空间分辨率的月降水量降尺度模拟数据,并利用区内141个气象站点数据对降尺度模拟数据进行精度验证。结果表明：（1）蒙古高原“植被区”植被对降水响应存在时滞性,约为一个月;“非植被区”多数月份白天与夜晚陆地表面温度差（LST＿D＿N）与降水量的相关性最显著。（2）降尺度模拟数据与气象站点数据具有较好的一致性,月尺度相关系数为0.83,各站点相关系数介于0.42～0.98。（3）在生长季、月平均尺度上,降尺度模拟数据具有较高精度,其中9月和10月数据精度优于TRMM 3B43数据。降尺度模拟数据整体精度较高,加之对原始数据在50°N以上未覆盖地区的填补以及空间分辨率的提高,可为区内水循环变化、农牧业生产、干旱监测等...     

探地雷达树木根系定位与直径估算

针对树木根系的探地雷达(Ground Penetrating Radar,GPR)检测图像复杂、解译困难、自动化程度低且精度不高等问题,该研究提出了一种基于YOLOv3的树根自动识别和参数估计的方法.通过不同的根预埋试验分析了根直径、掩埋深度和朝向对根系识别和预测的影响,对比评估了在复杂现场环境下该方法与商业软件常用的...     

包膜控释尿素（追施）对冬小麦生长发育及土壤硝态氮含量的影响

通过田间试验,研究了苗期和返青期追施释放期为30d和60d的包膜控释尿素对冬小麦生长发育及土壤硝态氮含量的影响。结果表明,分别在冬小麦苗期和返青期追施释放期为60d包膜控释尿素（N60N60）,能显著促进植株生长发育,增强植株对N、P、K养分吸收,增加籽粒产量。与不追肥（CK）处理相比,N60N60处理植株地上部和地下部干物重分别提高33.21%和67.84%;叶片叶绿素含量增加12.77%～25.20%;植株茎叶N、P、K含量分别增加63.55%、37.08%和6.91%,籽粒N、P、K含量分别增加8.56%、31.18%和24.49%;小麦穗长、穗粒重、千粒重和籽粒产量分别增加14.14%、27.00%、39.32%和48.01%。在返青期追施1次包膜控释尿素,N0N30优于N0N60处理,叶绿素含量增加1.50%～3.04%;植株茎叶N、P、K含量分别增加12.37%、12.25%和1.26%,籽粒N、P、K含量分别增加0.50%、5.69%和9.74%;小麦穗长、穗粒重、千粒重和籽粒产量分别增加2.84%、11.81%、11.65%和6.61%。同时,包膜控释尿素施用能明显减少硝态氮向土壤深层渗漏数量,减轻对地下水污染风险。     

Availability and extractability of soil manganese in a liming experiment

Abstract

The availability of soil Mn to corn in relation to extractability of soil Mn by EDTA, Mg(NO₃)₂, CH₃COONH₄, hydroquinone, H₃PO₄, and NH₄H₂PO₄ as affected by liming was evaluated under field conditions on a single soil type. EDTA, Mg(NO₃)₂ and CH₃COONH₄‐extractable Mn were related inversely to available Mn. No useful relationships were found between hydroquinone, H₃PO₄, and NH₄H₂PO₄‐extractable soil Mn and Mn uptake by sweet corn.     

Sulphur nutrition of clover: Effects of plant age on the composition‐yield relationship

Abstract

Five levels of S (as gypsum) were topdressed on to a pasture containing subterranean clover. Yield responses by the clover fraction of the pasture were measured, together with the total S concentration, the sulphate S concentration and the N:S ratio in young clover plants collected in autumn prior to the fertilizer application, and in plants from the control plots collected in winter and in spring.

As there were irregular changes in analytical values from autumn through winter to spring, a more detailed series of samples was taken in the second year. Therein, values for total S and sulphate S in clover plants from each treatment rose during the winter and fell during the spring, so that the critical concentration of sulphur or sulphate varied during the growing period. However, the critical N:S ratio was relatively stable, and in view of previously demonstrated correlations with response to added S, appears to be the more useful index for both diagnosis and prognosis.     

The Langmuir parameters of orthophosphate and pyrophosphate sorption for ammoniated tropical soils

Abstract

The Langmuir parameters of orthophosphate (OP) and pyrophosphate (PP) sorption for the ammoniated tropical soils were determined. Positive linear relationships between OP and PP sorption maxima and amounts of anhydrous NH₃ added were noticed. Indexes of bonding energy of OP and PP increased exponentially as ammoniation level of the soils increased from 33 to 100% of ammonia retention capacity.     

Kinetics of ammonia volatilization of anhydrous ammonia applied to a vertisol as influenced by Farm Yard manure,sorbed cations and cation exchange capacity

Abstract

In laboratory experiments, effects of added Farm Yard Manure (FYM), sorbed cations and cation exchange capacity (CEC) on NH₃ volatilization of anhydrous ammonia applied to a Vertisol were studied at 0.3 bar soil Moisture Tension and 25 ± 1°C. On addition of FYM or with increase in CEC the volatilization of retained ammonia was reduced while the effect of the sorbed cations was in the order : K‐Soil > Na‐Soil > Ca‐Soil > Mg‐Soil. The results suggest that the volatilization of retained NH₃ followed First order reaction kinetics, with a rapid rate of volatilization in the initial 8 to 10 h followed by a retarded rate up to 144 h.