不同供磷水平对辣椒根系形态和根际特征的影响

以辣椒品种线椒王为试验材料，采用盆栽方式，通过分析不同施磷水平下辣椒根系形态和根系生理的变化，探究辣 椒磷高效利用的主要根系及根际过程。结果表明，辣椒地上部和根系生物量随供磷水平的增加呈现先增加后下降的趋势，整 株磷浓度以及整株磷累积量呈增加趋势。随供磷水平增加，根系总根长呈先增加后下降趋势，根系平均直径、根冠比呈逐渐 降低趋势；辣椒根系菌根侵染率和土壤酸性磷酸酶活性呈现先增加后下降的趋势。相关分析结果表明，土壤有效磷浓度和整 株磷浓度与根系平均直径、菌根侵染率呈极显著负相关，与总根长可用一元二次方程拟合，表明辣椒根系适应低磷的根际特 征可能是通过增加根系生物量及总根长，同时降低根系平均直径来实现的。     

盐胁迫对黄瓜根系活力、叶绿素含量的影响

采用营养液水培添加2.925 g/LNaCl,研究了盐胁迫处理对黄瓜幼苗根系活力和叶片叶绿素含量的影响.结果表明:随着盐胁迫处理时间的延长,黄瓜幼苗根系活力呈现先升高后降低的变化趋势,叶绿素含量呈现下降的趋势;耐盐型品种长春密刺与盐敏感型品种津春2号相比,受盐胁迫的影响小.     

黑暗条件下不同贮藏方式和温度对辣椒穴盘苗质量的影响

以中椒22号辣椒为试材,在黑暗条件下研究不同贮藏方式及25、15、7℃温度对辣椒秧苗主要形态及生理指标的影响。结果表明:在贮藏过程中,辣椒秧苗的干重/鲜重、根冠比、根系活力、叶绿素含量明显下降,且7℃处理的下降幅度小于15℃和25℃处理;穴盘秧苗贮藏的横放效果好于竖放。贮藏结束后(9 d),15℃和25℃处理秧苗顶端会出现褐化现象。当秧苗定植到大田后,7℃处理的秧苗整体较其它处理生长速度快。表明7℃处理更适宜辣椒穴盘秧苗的贮藏。     

铝胁迫对辣椒叶绿素及叶绿素荧光的影响

在不同浓度铝胁迫下,以‘红辣椒王ⅡF1’、‘卡其特长条辣906’、‘汴椒1号’和‘苏长红’4个品种为材料,研究辣椒叶片叶绿体含量、叶绿素荧光参数的动态变化,以期为研究辣椒铝胁迫提供理论依据。结果表明,铝处理抑制辣椒叶片叶绿素的合成,从而降低辣椒叶片叶绿素的含量。辣椒叶片叶绿体色素(叶绿素a、叶绿素b、叶绿素a+b、叶绿素a/b)含量在低铝浓度(50μmol/L)下呈升高趋势,高铝浓度(200μmol/L)下则均下降。荧光参数的研究表明,随着铝胁迫的增加,初始荧光(F_0)随之增大,最大荧光(F_m)、原初光能转化效率(F_v/F_m)下降,植株抵抗逆境的能力下降,光合电子传递随之减小,最终导致光合速率下降。     

NaCl胁迫对莴笋种子萌发及幼苗根系生理生化指标的影响

研究了NaCl胁迫对2个莴苣品种种子萌发及幼苗生长的影响.研究结果表明,随着NaCl胁迫浓度的增大,对2个参试品种种子萌发及幼苗生长的抑制作用明显增强.同时采用营养液水培法,研究了盐胁迫对其幼苗根系活力、相对电导率、丙二醛(MDA)含量、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性的影响.研究结果表明,2个品种根系的相对电导率和MDA含量均随着NaCl浓度的增加呈现出增大的趋势,而2个品种的根系抗氧化酶(SOD和POD)活性和根系活力则随着NaCl浓度的增加而呈现出降低的趋势,并且每个盐浓度处理下相对电导率和MDA含量较对照的增强程度、SOD和POD活性和根系活力较对照的下降程度"攀研""绵兴".     

不同催芽温度对辣椒幼苗生长指标的相关性研究

以辣椒品种"羊角椒70号"为试材,研究了15、20、25、30℃恒温和25/15℃变温处理催芽温度对辣椒种子发芽的影响。结果表明:不同催芽温度对辣椒种子发芽率、发芽势、发芽指数及幼苗生长均有影响;采用25℃催芽,辣椒种子发芽率、发芽势、发芽指数分别达到97%、19%、23.42,且辣椒幼苗株高高、主根长长、叶片数多,幼苗地上部分、地下部分鲜干质量均最重,分别为18.40、9.04g和2.33、0.83g,25/15℃变温处理催芽主根长短、叶片数少,其它温度对辣椒幼苗生长差异不显著;不同催芽温度对辣椒幼苗根系活力的影响也不同,20、25℃处理辣椒苗根系活力最强,分别为108.0、109.4μg·g-1FW·h-1,30℃处理根系活力最弱为77.0μg·g-1FW·h-1;不同催芽温度处理辣椒幼苗干物质含量表现为T3(25℃)T4(30℃)T1(15℃)T5(25/15℃)T2(20℃),总叶绿素含量表现为T5T1T3T2T4,壮苗指数表现为T3T1T4=T5T2,G值表现为T3T1T2T5T4,根冠比表现为T1T3T4T5T2。综上所述,25℃处理是辣椒种子发芽的最佳温度,该试验可为宁夏地区辣椒集约化催芽技术和穴盘育苗提供理论依据和技术参数。     

低温弱光对辣椒叶片光合色素含量的影响

研究了低温弱光条件对2个辣椒品种光合色素含量的影响,结果表明:在亚适温弱光(100 μmol·m2·s-1,23℃/10℃)条件下,辣椒叶片的叶绿素a、b含量增加,叶绿素a/b降低,随着温度的降低,光照的减弱,叶绿素a、b含量逐渐降低,叶绿素a/b有上升趋势,低温弱光处理后,辣椒叶片类胡萝卜素含量降低.     

辣椒耐低温鉴定方法研究

以10个辣椒品种为试材,测定不同低温条件下的冷害指数和果长指数,并通过隶属函数法分析,以期建立辣椒耐低温鉴定方法及对不同辣椒品种进行耐低温性评价。结果发现,辣椒耐低温鉴定适宜温度为5℃,鉴定指标为冷害指数和果长指数;该条件下,7～8叶期的10个辣椒品种可划分为5个不同耐低温等级,其中,苏椒5号为强耐低温品种,龙椒16号和湘研11号为耐低温品种;结果表明,建立的辣椒耐低温鉴定方法结合了苗期和结果期的指标,简单易行、准确可靠,能更真实和准确地反映辣椒的耐低温实质,适用于不同辣椒资源耐低温的综合鉴定与评价。     

黄瓜根系分泌物对黄瓜幼苗生长和生理特性的影响

以"津春3号"黄瓜为试材,通过盆栽试验,研究了黄瓜根系分泌物对黄瓜幼苗生长、抗氧化酶活性、丙二醛含量、光合速率和根呼吸的作用,探讨黄瓜根系分泌物对黄瓜幼生长和苗生理特性的影响。结果表明:5%(v/v)处理能够促进黄瓜生长、根系呼吸速率增加、光合速率增强;其余处理随着黄瓜根系分泌物浓度的增加植株茎粗与茎高、根系呼吸速率、光合强度逐渐降低。     

施用炭化苹果枝粉末对平邑甜茶生长及根系构型的影响

选取冬季修剪下来的‘红富士’苹果枝条,分别在400、600 和700 ℃下厌氧炭化后粉碎过筛,按照1%和2%的质量比施入2 年生盆栽平邑甜茶的盆土中,调查平邑甜茶光合性能、植株生长量、根系活力和根系构型参数等。结果表明,3 种温度热解制备的炭化苹果枝粉末明显提高平邑甜茶叶片净光合速率、株高、干径和植株干质量,明显增加根活力、根系总长度、根系直径、根系表面积和根系体积,并且明显增大根系分形维数,使根系结构复杂化;在400 ~ 700 ℃的范围内,随着炭化温度升高,炭化苹果枝粉末对平邑甜茶的作用效果也逐渐升高;土壤施用2%的炭化苹果枝粉末的作用效果大于施用1%的处理。     

Growth and its partitioning in Prunus rootstocks in response to root zone temperature

Rootstocks for stone fruit varieties differentially influence tree physiology and one possible explanation for these differences is that varieties vary in their response to root zone temperature (RZT). To examine the effects of RZT, two trials using actively growing plants of five different Prunus rootstocks with chill requirements between 100 and 1100 h were undertaken. Plants were grown at RZTs of 5, 13 and 19 °C for 6 weeks after which total dry matter accumulation and its partitioning amongst roots, stems and leaves was determined. In general, the magnitude of total dry matter and its component parts positively correlated with RZT and significant differences were found among varieties in the magnitude of total dry matter accumulation. Individual varieties ranked differently at the three RZTs with respect to total dry matter: in general, the same ranking was also seen in the ranking of each growth component. RZT significantly influenced partitioning causing differences in leaf, stem and root mass ratios. These differences were greatest at low RZTs and became less as RZT increased. Several patterns of partitioning were found. Firstly, the low chill varieties (Okinawa and Flordagold) were little affected by RZT with similar partitioning occurring at each RZT. Secondly, the higher chill varieties, Green Leaf Nemaguard (GL), Golden Queen (GQ) and Fay Elberta (FE), reacted more strongly to RZT and were particularly affected by the lowest RZT. For these varieties, the root mass ratio rose and stem mass ratio fell as RZT increased. However, with respect to leaf mass ratio, two different trends were found: the leaf mass ratio for FE and GQ positively correlated with RZT whilst the relationship for GL was negative. These findings suggest that the response to RZT is related to a variety's chill requirement; offer an explanation for differences in performance of rootstock–scion combinations at different locations; and will aid the development of more accurate tree performance models by taking RZT into account.     

日光温室冬季基质加温效果及对番茄生长和品质的影响

采用控温电伴热加热系统对根系直接进行加温，设置基质加热温度分别为22、28、34 ℃，研究不同加热温度下根系温度场的分布以及对无土栽培番茄生长和品质的影响。结果表明，当使用椰糠作基质时，22、28、34 ℃的加热温度可在夜间使基质内中心位置平均温度分别提高到22.4、29.8、35.2 ℃； 与不加温对照相比，22 ℃和28 ℃加温处理能显著提高番茄单株产量，株高、茎粗、叶片数、根系干质量和鲜质量以及可溶性糖、可溶性固形物、可溶性蛋白、可滴定酸等品质指标显著提高；22 ℃加温处理中番茄植株的单株能耗为11.33 kWh，明显低于28 ℃处理的14.86 kWh，节能效果最优。     

萝卜贮藏期间木质素含量变化与糠心的关系

 对3 个红皮萝卜品种贮藏过程中肉质根不同部位木质素平均含量及糠心指数变化进行了研究。结果表明, 随着贮藏时间的延长, 糠心指数和不同部位木质素平均含量均增加; 木质素平均含量在贮藏后30 d 发生显著变化, 贮藏后50 d 达到极显著水平; 根皮部木质素含量变化较小, 且显著低于其它3 个部位; 糠心指数在贮藏后40 d 发生显著变化, 贮藏后50 d 达到极显著水平, 品种间不存在差异。通过回归分析得出, 根皮部木质素平均含量与糠心指数呈显著相关, 根头部、根中部和根下部木质素含量与糠心指数呈极显著相关。     

干旱胁迫下葡萄根系的生理生化变化与抗旱性的关系

以盆栽不同抗旱类型葡萄品种为试材,研究了干旱胁迫下,葡萄根系的生理生化变化。结果表明:葡萄根系的生理生化指标与抗旱性有密切的相关性。葡萄根系的相对电导率值,随着干旱胁迫程度的增加而增大,抗旱性强的品种其膜结构破坏相对要轻,其相对电导率变化小,因此其相对电导率值维持较低的水平;随干旱胁迫加强,不同葡萄品种根系组织中游离脯氨酸含量的变化呈现上升趋势,抗旱的葡萄品种,其游离脯氨酸含量变化明显大于不抗旱品种;干旱胁迫下,葡萄根系丙二醛含量增加,抗旱性弱品种增幅大,抗旱性强的品种增幅小;随着干旱胁迫程度的加强,过氧化物酶活性变化,表现为先上升后下降趋势,抗旱性强的葡萄品种,其根系过氧化物酶活性维持在较高的水平。     

不同黄瓜品种根系分泌物对根际土壤微生物及土壤养分的影响

研究以对枯萎病抗性不同华北生态型密刺类黄瓜品种秋棚、津研4号、中农13号、津优3号为试验材料,采用基质培的方式通过浸根法获得足量的由植物根系主动溢泌、可溶的根系分泌物提取液;采用仪器分析的方法系统研究不同品种间该类根系分泌物组分的差异.通过试验数据和图表的分析结果表明:黄瓜根系分泌物对于抗病黄瓜品种根区土壤中的真菌数量有促进作用,黄瓜植株的根系分泌物对黄瓜根区土壤的尖孢镰刀菌的增加具有明显的促进作用,且感病品种的促进作用强于抗病品种;不同抗性黄瓜的根系分泌物,对根区土壤的细菌的增加具有抑制作用,感病黄瓜品种的土壤中的放线菌的数量明显高于抗病品种;黄瓜根系分泌物对根区土壤中放线菌的影响,整体规律性不明显;黄瓜根系分泌物的存在提高了土壤三大营养元素的利用效率,同时提高了氮、磷、钾的速效比率.     

Beneficial roles of arbuscular mycorrhizas in citrus seedlings at temperature stress

Citrus, a cold-sensitive plant, often suffers from low temperature, which seriously affects citrus productivity. The objective of the study was to elevate the roles of an arbuscular mycorrhizal fungus, Glomus mosseae, in growth, photosynthesis, root morphology and nutrient uptake of citrus (Citrus tangerine) seedlings under temperature stress conditions. Three-month-old seedlings with or without G. mosseae were grown for 55 days at moderate temperature (25 °C) and low temperature (15 °C). Low temperature severely restrained symbiotic development including mycorrhizal colonization, entry point, vesicle and arbuscule relative to moderate temperature. Mycorrhizal seedlings grown at 25 °C maintained better stem diameter, plant height, leaf area, root and total dry weights, higher photosynthetic rate, transpiration rate and stomatal conductance, higher root volume, and more uptake of P, Ca and Mg relative to corresponding non-mycorrhizal control. However, mycorrhizal inoculation significantly increased only the root length and the Ca content of the seedlings grown at 15 °C. The results indicated that mycorrhizal formation had the beneficial effects on growth, photosynthesis, root morphology and part nutrient uptake of citrus seedlings grown at moderate temperature, but the beneficial roles of arbuscular mycorrhizas were almost lost at low temperature.     

10个苜蓿品种过氧化物同工酶（POD）分析

采用垂直板聚丙烯酰胺凝胶电泳技术，对10个苜蓿品种的根和叶作过氧化物酶（POD）同工酶分析。研究表明，不同器官酶谱带数目、迁移率（R）、酶活性及分布特征均有不同程度的差异。不同品种间酶谱带有较大差异，初步探讨了10个品种间亲缘关系。     

嫁接辣椒根腐病抗性及其与苯丙烷类物质代谢的关系

通过人工接种根腐病菌,观察不同品种辣椒砧木的发病率和病情指数变化,发现卫士发病晚,发病率低,病情指数最小,说明卫士的抗病性最强。以卫士为砧木,以赤峰特选甜椒(Capsicum annuumL.var.grossum Bailey)为接穗,自根辣椒为对照,研究嫁接对辣椒根腐病抗性及苯丙烷类代谢的影响,结果表明,嫁接植株的发病率和病情指数显著低于对照,高于砧木。接种前砧木与嫁接辣椒根系中的可溶性糖、苯丙氨酸解氨酶(PAL)活性显著高于对照,而叶片中的显著低于对照;酚类物质和木质素含量与对照差别不大。接种后辣椒根系中的可溶性糖含量逐渐降低,PAL活性、酚类物质和木质素含量先逐渐升高,10d后趋于平稳或有所下降。与对照相比,砧木和嫁接植株根系中的PAL活性、可溶性糖、酚类物质和木质素含量均显著增加,叶片中除可溶性糖含量显著降低外,其他指标也有不同程度的增加。说明嫁接可显著提高辣椒的根腐病抗性,其抗病机理与苯丙烷类物质代谢增强密切相关。     

Growth and establishment of container-grown London planetrees in response to mulch,root-ball treatment and fertilization

We conducted two experiments to evaluate the impact of cultural treatments on growth and establishment of container-grown London planetrees (Platanus × acerifolia’ Bloodgood’). In both experiments, 48 trees grown in 100 l (#25) black plastic containers were assigned at random to one of three root-ball treatments prior to planting; no treatment (Control), outer 3 cm of roots removed around entire root-ball (Shave), or outer circling roots disentangled from the root-ball (Tease). In Experiment 1, half of the trees were fertilized with 400 g of controlled release fertilizer (15-9-12; N-P₂O₅-K₂O) at planting and the remainder of the trees were not fertilized. In Experiment 2, half of the trees were mulched with an 8 cm deep × 2 m diameter ring of coarse ground pine bark at planting and the remainder of the trees were not mulched. In Experiment 1, fertilization at planting increased SPAD chlorophyll content on two of four measurement dates but did not affect cumulative height or caliper growth after two years. After two growing seasons, root-ball treatments (shaving or teasing) increased root growth outside the original root-ball compared to control trees. Both root-ball treatments also reduced circling roots. In Experiment 2, mulching at planting increased soil moisture and cumulative tree height and diameter growth. Shaving increased new root growth and both root-ball treatments improved root architecture and reduced circling roots. Overall, the study demonstrates that root-ball manipulations can stimulate new root growth and reduce circling roots. Mulch is a valuable aid to conserve soil moisture and increase tree growth. Fertilization at planting provided little benefit in this experiment, which may have been related to a high level of soil fertility at the site or nutrient loading of the trees from nursery culture prior to transplanting.