土壤水分对烤烟生长、物质分配和养分吸收的影响

采用室内盆栽试验研究了不同土壤含水率对烤烟生长、物质分配和养分吸收的影响。结果表明,烤烟株高随土壤含水率的增加而增高;生物量随土壤含水率的降低而减小,其减幅为叶茎根,而根冠比则与土壤含水率成反比,反映了烟草对土壤水分含量差异响应的整体特征。不同生育期叶绿素对土壤含水率的响应不同,团棵期、旺长期和成熟期的土壤相对含水率分别为70%～75%、80%～85%和50%～55%时,各处理中叶绿素含量最高。各处理烤烟对养分的吸收表现为对N、K吸收量显著大于P,且当土壤含水率低于烤烟所需的适宜含水率时,随着土壤含水率的降低,烤烟茎、根的养分吸收量均有不同程度的升高,但叶中却有所下降;而各生育期根、茎、叶在土壤含水率过高的情况下,对养分N、P、K的吸收均显著降低。     

水磷耦合对冬小麦幼苗营养元素含量的影响

本文研究了速效水范围内水磷耦合对冬小麦幼苗的N、P、K吸收量的影响。结果表明:不同速效水水平对小麦苗期N、P和K的吸收有明显影响。在不同的P水平处理时最高N、P吸收值都出现在速效水高的处理上,低水时N、P吸收也较低。中P与高水配合有利于N、P的吸收。低速效水时提高P水平可促进P吸收,但不能显著提高N吸收。速效水的水平对K吸收影响不如对P吸收影响明显,品种间差别不大。结果还显示土壤低P处理显著降低植株幼苗对P素的吸收,不同速效水水平时增加土壤P可以提高植株吸P量。土壤缺P对小麦植株K吸收有一定影响,水磷耦合后品种间的K吸收量差异加大。     

东方百合养分吸收规律和分配特点的研究

本文通过温室田间实验,研究了东方百合的养分吸收规律和分配特点。结果表明,现蕾以前,以消耗鳞茎中的养分为主,供应百合植株生长;由现蕾开始,历时30天,为百合吸收氮素的高峰期,现蕾始历时45天为百合吸收磷的高峰期,钾的吸收较早,由展叶期开始,直至切花期,共计75天。氮、磷、钾在各器官的分布:现蕾以前以叶片为主,茎秆次之,地下部最少;随着百合的生长,地下部养分比重上升,进入切花期后,茎、叶养分降低,以地下部和花蕾为主。百合吸收氮、磷、钾的比值:现蕾以前为1∶0.17∶1.08,现蕾以后为1∶0.15∶1.45。     

烤烟根系分泌物对烤烟幼苗生长和养分吸收的影响

连作是烟草栽培中的普遍现象,已引起生长抑制、产量下降和品质恶化等问题。本试验采用溶液培养的方法,在培养液中分别加入未分组和分组后的烤烟根系分泌物,研究根系分泌物对烤烟幼苗生长和养分吸收的影响。结果表明,加入未分组的烤烟根系分泌物显著抑制幼苗的生长,降低根系活力,并随加入量的增加抑制作用增强;加入酸溶性、碱溶性、中性组分的根系分泌物,均降低幼苗根系活力,以中性组分的抑制作用较强。三种不同组分的根系分泌物均显著降低根系对NO3-、PO43-、K+离子的吸收,其中中性组分对NO3-吸收的影响最大,而酸溶性组分对K+的吸收抑制作用较强。推测在烤烟根系分泌物中,可能存在多种抑制烤烟生长和养分吸收的化学物质。     

钾素营养对烤烟生长及养分吸收的影响

同钾素浓度处理的砂培试验表明,150mgkg-1的钾素浓度处理其及以下的浓度处理烤烟都出现不同程度的缺素症状。烟叶干物质有随着钾素浓度的增加而增加的趋势。烟叶在不同生育期内对钾素的吸收和累积都是与钾素的供应呈正相关。磷的吸收与钾的供应呈一定的正相关。全氮在烟株体内分布趋势是根>叶>茎,全钾分布趋势是叶>茎>根,磷多集中在根部,叶内含量较少。烟草钾与钙、镁的吸收存在颉颃作用。     

供镁水平对烤烟生长及养分吸收的影响

采用盆栽土培试验研究了不同供镁水平对烤烟生长和养分吸收的影响。结果表明,施MgSO4量为0.06～1.08 g/kg时,各处理烤烟的生长状况和干物质积累量明显优于对照和施MgSO4 1.88 g/kg。烤烟各器官对钾的吸收最多,氮次之,磷最少,各处理表现一致。施MgSO4量为0.18～0.72 g/kg的3个处理烤烟各器官对氮磷钾的吸收量明显高于其他处理,且在施MgSO4量为0.36 g/kg时达到峰值。当施MgSO4量较低（≤0.06 g/kg）或较高（MgSO4≥1.08 g/kg）时都会抑制烤烟的生长发育、干物质和养分的积累。而烤烟各器官对镁的吸收量则均表现出随施镁量增加而增加的趋势,且各器官镁吸收量表现为:叶＞茎＞根;镁肥的施用能够在一定程度上促进烤烟对镁素的吸收。     

不同供氯水平对烤烟生长发育和养分吸收的影响

采用田间小区试验研究了不同供氯水平对烤烟生长发育和养分吸收的影响.结果表明,施氯能促进烤烟生长发育,尤其当供氯水平为90.0 kg·hm~(-2)时,烤烟株高明显优于对照和其余处理.供氯水平在45.0～90.0 kg·hm~(-2)的范围内,烟叶对氮的吸收量明显高于其他处理,且在供氯水平为90.0 kg·hm~(-2)时达到峰值.施氯促进烤烟对钾的吸收,但烟叶中K_2O/Cl随供氯水平增加而降低.氯与磷之间存在着拮抗关系.在22.5～67.5 kg·hm~(-2)施氯范围内,烟叶含钙量随着氯水平增加而增加.在22.5～45.0 kg·hm~(-2)施氯范围内,施氯促进烟叶对镁的吸收.烟叶各叶位对氯的吸收量则表现出随供氯水平增加而增加的趋势,且各叶位氯吸收量表现为下部叶>中部叶>上部叶.供氯水平在22.5 kg·hm~(-2)时,上中下部烟叶的氯含量均在最佳范围(0.3%～0.8%)内.     

15N示踪研究烤烟对氮的吸收及分配

采用盆栽试验，利用^15N示踪研究了烤烟对不同形态氮的吸收利用规律。结果表明，烤烟各部位叶片对氮素的积累量表现为中部叶〉上部叶〉下部叶；肥料氮进入的比例具有下部叶〉中部叶〉上部叶的规律。不同生育期肥料氮进入烟叶中的比例，以团棵期最高，之后肥料氮进入的比例减少，统计分析结果表明（5％水平），从现蕾期到成熟期之间差异不大。同位素^15N标记肥料施入土壤后约39％～53％被烟株吸收利用，约22％～41％损失，约20％～37％残留于土壤中。     

不同氮磷钾施肥量对烤烟农艺性状及养分吸收的影响

研究氮磷钾用量对烟草生长和叶片养分吸收的影响,大田试验结果表明,不同水平的N、P、K施肥量明显影响烟株的长势,影响程度N>K>P,综合考虑产量和上等烟比例,以施肥量N 112.5 kg/hm2、P2O5112.46 kg/hm2、K2O 269.84 kg/hm2的N2P2K2处理最好,某种元素不足或过量都会降低上等烟比例。施用适量的氮有利于烤烟中N和K的吸收,而过量50%的N3水平的氮使烟草钾含量降低了11%。磷浓度过高或过低都会降低N和K的积累。增施K肥有利于N和K的积累,其中钾含量最高增长幅度可达37%。随着氮用量增加,上等级烟氮肥农学利用率呈直线下降的趋势,而磷、钾农学利用率在一定氮磷钾用量范围内增加。     

烟草对土壤铅的吸收、转运及分配特征

采用室外盆栽试验方法,开展烟草不同生育期铅吸收转运及分配特征的研究。结果表明：土壤铅处理对烟草生长有较明显的抑制作用,且生育前期比生育后期更明显;烟草根系对铅的阻滞作用较强,以限制铅由根系向地上部运输。烟草各生育期根、茎和叶中铅含量均随土壤铅浓度的增加而升高,其中根部的上升幅度最大,随着生育期的推进,烟草各器官铅含量从团棵期至现蕾期呈现先降低后升高的趋势,根部铅含量从现蕾期至成熟期呈现下降趋势。土壤添加外源铅后,烟草生育期内茎和叶的铅转运系数分别介于0．35—1．00和0．25～0．91之间,茎和叶的转运系数随着铅浓度的增加和生育期的推进呈下降趋势。烟草各器官中铅含量介于13．8～180．74mg·kg^-1之间,各器官铅含量的分布规律为根〉茎〉叶,各器官铅积累量总体为叶〉根〉茎,但成熟期在T2和T3处理下表现为根〉叶〉茎。在土壤铅浓度较低时,烟草体内铅较易向地上部分转运,旺长期至现蕾期阶段是烟草体内铅向地上部分转运的关键时期。     

烤烟烟叶自动分级的智能技术

研究烤烟烟叶自动分级中的几种智能技术,提出应用图像处理技术提取烟叶质量特征参数,应用模糊统计技术确定特征参数对各组与各级的隶属度,以及应用综合评判技术判定样本的组别与级别等方法,并给出对云南产烟区烟叶样本的分级结果。分级结果表明,该系统已达到人类专家分级水平,并具有积累分级经验的智能特性     

不同装土量对玉米植株全量养分含量及吸收量的影响研究

以松辽平原玉米带黑土区现行耕作制度下产生的两种不同的剖面构型“波浪型”和“平面型”导致有效土量差异为背景,采用室外盆栽模拟实验,研究了不同装土量对苗期、抽雄期和成熟期玉米植株全氮、全磷、全钾含量以及吸收量的影响。结果表明：随装土量增加,苗期、抽雄期和成熟期玉米植株全量养分吸收量增加,并且全量养分含量苗期最高,随着时间的推移含量逐渐递减,苗期到抽雄期下降速率最快,而抽雄期以后降幅不大。     

不同起垄覆膜方式对土壤水分及烟株前期生长的影响

为探索干旱地区土壤保水的有效措施，研究了不同起垄覆膜方式对土壤水分及烤烟前期生长发育的影响。结果表明。覆膜有利于提高土壤含水量，从而有利于烟株生长对水分的需求，覆膜土壤含水量高于不覆膜土壤，覆膜烟株生长及抗逆性明显高于不覆膜烟株。不同起垄覆膜方式相比较，土壤含水量及烟株前期生长指标及抗逆性表现为，冬前起凹垄。覆膜〉起凹垄，覆膜〉起凸垄，覆膜〉起凸垄。不覆膜，说明提早起垄、垄面为凹形并进行覆膜处理是干旱地区提高烤烟移栽质量，促使烟株早生快发，增强烟株抗逆性的有效手段之一。     

Potassium and Nitrogen Distribution Pattern and Growth of Flue-Cured Tobacco Seedlings Influenced by Nitrogen Form and Calcium Carbonate in Hydroponic Culture

ABSTRACT

Grape tomatoes (Solanum lycopersicon L. var. cerasiform) have recently gained in popularity among consumers because they can be eaten without being cut, they are deep red in color, and their flavor is intense and pleasant. Current nitrogen (N) fertilization recommendations were developed for determinate tomato varieties that have a 3-month long growing season, whereas that of the indeterminate grape cultivars may be up to six months. ‘Tami G’ grape tomatoes were grown on a Lakeland fine sand at the North Florida Research and Education Center—Suwannee Valley, near Live Oak, FL in Springs 2005 and 2006 using standard plasticulture practices under 0%, 33%, 66%, 100%, 133%, and 166% of the current recommended N rate for round tomato (224 kg/ha). Due to a longer growing season in 2006, plants received an additional three weekly injections of 22 kg/ha of N each in the 100% rate, that were also proportionally applied to the other treatments. Tomatoes were transplanted March 24, 2005 and April 4, 2006 and harvested, weighed and graded five (2005) and seven (2006) times. Season marketable yield (SMY) responses to N rates were quadratic (both years P < 0.01) and highest SMY (40,340 and 36,873 kg/ha) occurred with 314 and 280 kg/ha of N in 2005 and 2006, respectively. Fruit soluble solids concentrations ranged from 6.25 to 7.5, and 7.0 to 8.3° Brix in 2005 and 2006, respectively, and were not significantly affected by N rate. These results suggest that N fertilization for grape tomato grown in Spring with plasticulture could be done by incorporating 56 kg/ha of N in the bed, followed by daily rates ranging from 0.5 to 3.5 kg/ha/day. Because the length of the growing season for grape tomato may vary, emphasis should be placed on daily N rates and irrigation management, rather than on seasonal N rate.     

移栽期和氮肥对烤烟产量、产值及氮素吸收利用的影响

采用大田15N同位素示踪试验,在湖北襄樊2个不同海拔的植烟生态区,研究了3个不同烟苗移栽期及施用氮肥对烤烟产量、产值和氮素吸收、利用及分配的影响。结果表明,低海拔和高海拔植烟生态区施用氮肥烤烟产量分别增加29%和19.2％,产值分别增加24.8%和25.7%。与5月5日移栽相比,推迟移栽期（5月15或25日）对低海拔地区烤烟产量产值影响不明显,但显著提高高海拔地区烤烟产量产值10%～30%。对烤烟总氮累积量的分析表明,推迟移栽期,低海拔地区植株吸氮量增加25%～45%,而高海拔地区植物吸氮量下降6%～20%。低海拔和高海拔试验点烤烟的地上部氮肥利用率分别约为30%和21%。推迟移栽期显著提高生育前期氮肥利用率,但在中后期无明显影响。与总氮积累趋势相反,推迟移栽期,烤烟各部位肥料氮占总氮的比例,低海拔地区下降10%～40%,而高海拔地区增加15%～50%。在高海拔地区,5月中下旬移栽烟苗有利于肥料氮素的吸收利用和增产增收作用。     

湘南典型植烟土壤养分供应及烟株吸收特征

养分是烤烟生长与烟叶品质形成的基础，为探究烤烟大田生育期间土壤养分供应、烟株养分吸收以及两者匹配情况及其与烟叶品质问题的关系，本研究测定和分析了湘南目前施肥模式下典型植烟土壤速效养分含量（铵态氮、硝态氮、有效磷和速效钾）、表观肥料养分利用率、烟株养分吸收以及有关烟叶品质指标，并监测了烤烟大田生育期间的气候条件及土壤温湿度变化状况。结果表明：①施氮总量较高(183 kg/hm2)，且基施氮量占比高(48.4%)，烤烟大田生育前期(0~36 d)土壤速效养分丰富，但烟株生长较慢，导致当季肥料养分利用率不高；②最后一次追肥时间(43 d)偏晚，使得后期烟株脱氮困难，造成顶叶和上二棚叶烟碱含量过高，还原糖含量偏低；③早春低温是烤烟大田生育前期烟株生长缓慢的重要影响因子。针对目前施肥模式与烟株养分需求不匹配问题及其主要影响因素，提出减施基肥、适时适量追肥的优化施肥模式以及应用控缓释肥料、促生微生物、高效多功能叶面肥和施加外源碳等对策。     

Effects of Zinc Application on Growth,Absorption and Distribution of Mineral Nutrients Under Salinity Stress in Soybean (Glycine Max L.)

The purpose of the present work was to evaluate effects of zinc application on growth and uptake and distribution of mineral nutrients under salinity stress [0, 33, 66, and 99 mM sodium chloride (NaCl)] in soybean plants. Results showed that, salinity levels caused a significant decrease in shoot dry and fresh weight in non-zinc application plants. Whereas, zinc application on plants exposed to salinity stress improved the shoot dry and fresh weight. Potassium (K) concentration, K/sodium (Na) and calcium (Ca)/Na ratios significantly decreased, while sodium (Na) concentration increased in root, shoot, and seed as soil salinity increased. Phosphorus (P) concentration significantly decreased in shoot under salinity stress. Moreover, calcium (Ca) significantly decreased in root, but increased in seed with increased salinization. Iron (Fe) concentration significantly decreased in all organs of plant (root, shoot, and seed) in response to salinity levels. Zinc (Zn) concentration of plant was not significantly affected by salinity stress. Copper (Cu) concentration significantly decreased by salinity in root. Nonetheless, manganese (Mn) concentration of root, shoot, and seed was not affected by experimental treatments. Zinc application increased Ca/Na (shoot and seed) ratio and K (shoot and seed), P (shoot), Ca (root and seed), Zn (root, shoot, and seed) and Fe (root and shoot) concentration in soybean plants under salinity stress. Zinc application decreased Na concentration in shoot tissue.     

湖南烤烟总糖、还原糖含量与几种土壤养分的关系分析

研究了湖南烤烟177份烟叶样品糖含量与土壤养分的关系。结果表明:(1)烟叶糖含量在样品间存在着广泛的变异,B2F、C3F和X2F等级的总糖含量分别为22.28±3.32%、24.84±2.91%和24.18±3.49%,还原糖含量分别为19.69±2.47%、22.10±2.55%和21.33±3.08%;(2)不同等级烟叶中糖含量与土壤全氮和碱解氮含量呈负相关,而与土壤全钾和速效钾含量呈正相关,但不同等级烟叶中影响糖含量的主导因子不尽一致;(3)对土壤中全氮、全钾、碱解氮和速效钾含量进行分组,研究了烟叶总糖和还原糖含量在不同组间的变化,表明烟叶糖含量一般随土壤钾素含量增加而增加,随土壤氮素含量增加而降低。     

Investigation of Associations Between Rhizosphere Microorganisms and the Chemical Composition of Flue-Cured Tobacco Leaves Using Canonical Correlation Analysis

Canonical correlation analysis was applied to determine the relationship of rhizosphere microorganisms to common chemical components in flue-cured tobacco leaves. The results were as follows: (1) The chemical composition of the tobacco was related to the major microbial physiological groups in the rhizosphere soil. No close relationship was found with the populations of bacteria, fungi, and actinomycetes. (2) Greater contents of total nitrogen and potassium in tobacco leaves were associated with larger populations of aerobic nitrogen-fixing bacteria and with smaller populations of aerobic cellulose-decomposing bacteria. In addition, potassium content was also negatively correlated with nitrosobacteria counts but showed no close relationship with the potassium bacteria in the rhizosphere. The nicotine content was associated with greater populations of nitrosobacteria and nitrobacteria, and the content of water-soluble total sugar was positively correlated with the counts of nitrosobacteria.