Metabolism, uptake and translocation of 14C-paraquat in resistant and susceptible biotypes of Crassocephalum crepidioides (Benth.) S. Moore

The metabolism, uptake and translocation of paraquat in resistant (R) and susceptible (S) biotypes of Crassocephalum crepidioides (Benth.) S. Moore (redflower ragleaf) at the 10-leaf stage was investigated. A study on the properties of leaf surface was carried out to examine the relationship between leaf surface characters and paraquat absorption. The extractable paraquat was not metabolized by the leaf tissue of either the resistant or susceptible biotypes. Differential metabolism, therefore, does not appear to play a role in the mechanism of resistance. Both biotypes did not show any significant difference in the amount of cuticle and trichome densities. Furthermore, both biotypes are identical in the structure of stomata, trichomes and epicuticular wax. The results of the leaf surface studies are in agreement with the findings of the uptake study. Both biotypes demonstrated no significant difference in absorption between the resistant and susceptible biotypes. However, 10% of the absorbed ¹⁴C-paraquat into the S biotype was translocated basipetally, but not in the R biotype. The results of this study suggest that in C. crepidioides , differential translocation may contribute to the mechanism of resistance at the 10-leaf stage.     

局部灌水方式对冬小麦产量与水分利用的影响

以根系对土壤水分的吸收利用规律、土壤养分在土层中的分布规律和农田土壤蒸发特征为基础,研究局部不同节水高产灌水方式,是解决水肥异位问题和实现“浇作物”的新尝试。2000～2002年连续两年的试验结果表明,测坑内灌溉5水的处理与筒栽灌溉7水的处理有最高的产量和千粒重,适宜的灌水量是30mm。提高作物产量和水分利用效率的灌溉方式应该是灌水集中在作物主要根系分布层,实施高频局部灌溉。     

Ameliorative effects of inoculation with the plant growth-promoting rhizobacterium Pseudomonas sp. DW1 on growth of eggplant (Solanum melongena L.) seedlings under salt stress

The objective of this work was to evaluate the effect of inoculation with the plant growth-promoting rhizobacterium Pseudomonas sp. DW1 on eggplant (Solanum melongena L.) growth, mineral uptake and activities of the antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) of plant leaves under salinity stress. The study was conducted in pot experiments using eggplant (S. melongena L., cv. Yinjia) and a coastal soil. The NaCl concentration of the coastal soil was 0.57 g (kg soil)⁻¹. Four NaCl levels were tested: 0.57, 1.0, 2.0, and 3.0 g NaCl (kg soil)⁻¹, by adding NaCl to soil, respectively. Pseudomonas-inoculated seeds had an increase in the germination percentage over its non-inoculated seeds under salinity. Salinity negatively affected growth of eggplant; however, plants inoculated with Pseudomonas sp. DW1 grew to a significantly greater extent than plants that were not treated with this bacterium. Salinity significantly decreased K⁺ concentration, increased Na⁺ concentration, and did not significantly decrease Ca²⁺ content in shoots of eggplants. Inoculating with Pseudomonas sp. DW1 increased shoot Ca²⁺ of eggplant compared to the non-inoculating eggplant plants under salinity. Inoculating treatments with Pseudomonas sp. DW1 had no effect on shoot Na⁺ concentration in 0.57 and 1 g (kg soil)⁻¹ NaCl, but there were significant decreases in inoculated treatments than in non-inoculated ones at 2 and 3 g (kg soil)⁻¹ NaCl. Salinity decreased SOD activities and increased POD activities, and inoculated Pseudomonas sp. DW1 had an increase effect on SOD activity in the leaves of eggplants. Alteration of mineral uptake and increase in the antioxidant enzyme activities may be two mechanisms for the alleviation of salt stress. Based on the results of the experiment reported herein, the use of the plant growth-promoting rhizobacterium treatment may provide a means of facilitating plant growth under salt stress.     

NaOH改性稻秆对亚甲基蓝染料吸附性能的研究

为解决农村稻秆的资源化利用问题,将稻秆用NaOH改性做吸附剂处理亚甲基蓝染料废水;考察pH值、吸附剂投加量、染料浓度和温度对染料吸附性能的影响;分析改性稻秆对亚甲基蓝染料的吸附动力学过程。研究结果表明,亚甲基蓝浓度为150mg/L,pH值为12、吸附剂投加量为4g/L时,改性稻秆对亚甲基蓝染料有很好的去除效果,染料的吸附率达到98.1%;改性稻秆对亚甲基蓝染料的吸附符合Freundlich等温模型,最大吸附量为52.910mg/g,升高温度能够增加吸附剂对亚甲基蓝染料的吸附效果;改性稻秆吸附亚甲基蓝是一个快速吸附过程,符合伪二级吸附动力学方程。     

基于无人机遥感影像的冬小麦氮素监测

精准氮素管理是一项提高作物氮肥利用效率的有效策略,利用无人机遥感技术精确估测小麦氮素状况是必要的。试验在山东省乐陵市科技小院实验基地进行,利用八旋翼无人机搭载Mini-MCA多光谱相机于2016年获取冬小麦4个关键生育时期(返青期、拔节期、孕穗期、扬花期)冠层多光谱数据,同步获取地上部植株样品并测定其生物量、吸氮量、氮营养指数,及成熟期籽粒产量,根据各关键生育期与全生育期分别构建植被指数与农学参数回归分析模型,评估基于无人机遥感影像的冬小麦氮素营养诊断潜力。结果表明:基于无人机遥感影像能够较好地估测冬小麦氮素指标(R2为0.45~0.96),决定系数随着生育期推移而逐渐增大。拔节期、孕穗期和扬花期估产效果接近且具有很好的估测能力,扬花期DATT幂函数模型对小麦氮营养指数的解释能力最强(R2=0.95)。因此,以多旋翼无人机为平台同步搭载多光谱相机对冬小麦有较好的氮素诊断潜力,可利用估测结果指导精准氮肥管理。     

High potassium to magnesium ratio affected the growth and magnesium uptake of three tomato (Solanum lycopersicum L.) cultivars

Potassium(K) and magnesium(Mg) levels and their balances are two factors affecting the growth of plant. However, the responses of different crop cultivars to K/Mg ratios are less clear. This study was aimed at assessing the different responses of tomato(Solanum Lycopersicum L.) cultivars to the different K/Mg supply ratios. Three tomato cultivars(Zhongza 9(ZZ), Gailiangmaofen(MF), and Jinpengchaoguan(JP)) were grown in pots with three different K~+/Mg~(2+) ratios(4:0, 4:1 and 8:1, represented by K/Mg_(4:0), K/Mg_(4:1), and K/Mg_(8:1), respectively). Compared with K/Mg_(4:1) treatment, the leaf chlorophyll content, net photosynthetic rate, and total biomass of tomato seedlings under K/Mg_(4:0) treatments were decreased by 69.7, 89.1, and 53.1%, respectively. The Mg deficiency symptoms were observed when the Mg content in shoot became lower than 4 mg g~(–1) DW. Compared with K/Mg_(4:1) treatment, total biomass of tomato seedlings of K/Mg_(8:1) treatment was decreased by 21.6%; the shoot and root Mg contents were decreased by 10.4 and 21.8%, respectively; and Mg uptake of tomato was reduced by 34.1%. There were significant differences in biomass and Mg uptake for the three cultivars between the different K~+/Mg~(2+) treatments. The Mg uptake of the three different cultivars ranked as ZZJPMF under Mg deficiency and high K condition. In conclusion, the growth and Mg uptake and allocation of tomato were influenced significantly by imbalance K and Mg supply. JP and ZZ were the cultivars with the highest efficiency in Mg uptake.     

花生硫素营养特性的研究

对花生的硫素营养特性进行了研究 ,结果表明 :施硫均能显著提高花生各生育阶段对N、S的吸收量 ,提高其N、S含量 ,降低N S比 ,提高花生盛花期以后的N积累比例 ,明显促进S养分向花生籽实部分运转。在不同硫肥品种中 ,以石膏促进花生吸收N、S,提高其N、S含量的效果最好。花生在始花～盛花期吸收硫的强度最大     

甜菜子叶期幼苗硝态氮吸收特性及其与硝酸还原酶活性的关系

６个有代表性的甜菜品种在人工气候室的营养液培养试验表明，甜菜子叶期幼苗对ＮＯ３＾－的吸收要经最初２ｈ的适应阶段后才可均匀进行。均匀吸收后，观察到多倍体的吸收量〉２倍体，倍性相同品种中Ｅ型〉ＮＥ型〉ＮＺ型〉Ｚ型的初步结果。不同类型品种间ＮＯ３＾－吸收的表观米氏常数（Ｋｍ，ａｐｐ）、最大吸收速率（Ｉｍ）有明显差异，除多倍体ＮＺ型品种甜研３０１的Ｋｍ，ａｐｐ较低而Ｉｍ较高外，其余品种的Ｋｍ，ａｐｐ和Ｉｍ     

小麦/玉米/大豆三熟套作体系中小麦根系分泌特性及氮素吸收研究

为探讨小麦/玉米/大豆多熟套作体系下小麦根系分泌物的分泌特性及其对根系生长环境和植株氮素吸收的影响,2006-2008年连续两个生长季采用田间定位试验,研究了小麦-大豆、小麦-甘薯、小麦/玉米/大豆和小麦/玉米/甘薯4种种植模式下小麦根系分泌物的数量与种类、小麦根系生长、土壤水分、土壤氮含量及植株吸氮量的变化特性。结果表明,与小麦-大豆和小麦-甘薯两种净作模式及小麦/玉米/甘薯套作模式相比,小麦/玉米/大豆套作降低了开花期和成熟期小麦生长区的土壤湿度、pH值及NO₃^--N和NH₄⁺-N的含量,提高了小麦植株地上部总吸氮量、根系活力、根干重及土壤总氮含量,并且,开花期小麦根系分泌有机酸总量和可溶性糖含量增加,表现为套作>净作,大豆茬口>甘薯茬口,边行>中行,其中以小麦边行处理的分泌量最高。拔节期根系分泌的有机酸,净作处理以乙酸含量较高,占总量的47.8%~51.6%,套作处理以柠檬酸含量较高,占总量的31.7%~55.1%;开花期根系分泌的有机酸,净作和套作处理均以乙酸含量较高,占总量的33.3%~78.3%。小麦/玉米/大豆套作对小麦根系分泌有机酸和可溶性糖有促进作用,从而改善了根系生长环境,提高了小麦对氮素的吸收。     

有效碳对菹草光合作用及吸收氮、磷的影响

作者研究了有效碳（ＣＯ＿２、ＨＣＯ－＿３）对菹草光合作用及吸收氮、磷的影响。水中缺乏游离ＣＯ＿２时，菹草的光补偿点提高，光饱和点下降，对氮、磷营养盐的吸收速率显著降低。２５℃、最适光阴、强光而下，菹草进行正常氮代谢所需ＨＣＯ－＿３的临界浓度（ｍｍｏｌ·Ｌ￣（－１））分别为０．１８，０．２５；进行正常磷代谢所需ＨＣＯ－＿３的临界浓度（ｍｍｏｌ·Ｌ￣（－１））分别为０．３２，０．４０。不良光照和高ｐＨ下缺乏有效碳源使菹草的氮、磷代谢受阻而导致夏季菹草衰败死亡。