灌浆期水稻受褐飞虱侵害后赤霉素含量的变化

应用酶联免疫吸附法(ELISA)研究灌浆期水稻协优963、TN1受褐飞虱Nilaparvata lugens(Stl)若虫侵害后根、叶片赤霉素(gibberellin,GA)含量的变化,以探讨褐飞虱若虫侵害后灌浆期水稻耐虫性与植物体内源激素的关系。结果表明:虫口密度40头/株和80头/株120头/株侵害灌浆期水稻协优963后3d根GA含量显著下降,40头/株和80头/株侵害后协优963后3d根冠(叶片)比显著下降;40头/株侵害协优963后6d根冠比显著下降。40头/株、80头/株和120头/株侵害灌浆期水稻TN1后3d根GA含量显著下降;80头/株和120头/株侵害TN1后6d根GA含量显著下降,120头/株侵害TN1后6d根冠比显著下降。表明灌浆期水稻协优963、TN1受褐飞虱若虫侵害后基本变化趋势为根GA含量、GA含量根冠比下降(3d、6d),叶片GA含量变化规律不明显;耐、感虫水稻品种变化一致,变化幅度无明显差异。     

褐飞虱胁迫下两种水稻不同生育期玉米素核苷含量动态

应用酶联免疫吸附法（enzyme-linked immunosorbent assay, ELISA）研究了在褐飞虱胁迫下镇稻2号（粳稻）和协优63（籼稻）抽穗期和灌浆期水稻叶片和根中玉米素核苷（zeatin riboside, ZR）含量变化情况。结果表明, 镇稻2号抽穗期ZR含量变化比灌浆期对褐飞虱侵害更为敏感,密度分别为15、30、60、120头/株的褐飞虱侵害水稻抽穗期3、6、9天后,叶片和根中ZR含量显著下降;灌浆期除各个褐飞虱密度侵害9天叶片中ZR含量和120头/株褐飞虱密度侵害9天根部ZR含量显著下降外,其他处理根和叶片中ZR含量下降不明显。协优63抽穗期受褐飞虱侵害后体内ZR的变化不同于镇稻2号,密度分别为15、30、60头/株的褐飞虱侵害3天后,叶片中ZR含量明显升高;在灌浆期,除30、60、120头/株褐飞虱密度侵害6天和120头/株褐飞虱密度侵害9天叶片中ZR含量有显著增加外,其他处理变化不明显。表明不同品种水稻在不同密度褐飞虱侵害下对根和叶片中ZR含量有不同的影响。     

褐飞虱侵害对不同抗性水平水稻根部吸收氮、磷、钾的影响

为了解褐飞虱Nilaparvata lugens侵害后水稻抗性水平与根系吸收氮（N）、磷（P）、钾（K）的关系,对不同抗性水平的水稻受褐飞虱侵害后的平均受害水平、植株功能损失指数及水稻吸收水培液营养元素N,P,K情况进行了研究。结果表明：不同水稻品种（TN1、协优63、协优963和超级培矮64S/E32）接种褐飞虱后,TN1受害最严重,协优63和超级培矮64S/E32 次之;受害最轻的是协优963,30头/株侵害后植株功能损失指数仅为0.661。40,60和80头/株侵害水稻后根系对K吸收下降程度最显著,其次为P,最后为N;且随褐飞虱侵害时间的延长（6 d, 9 d）影响愈显著。60头/株侵害TN1、协优63、协优963和超级培矮64S/E32后9 d,根系对K吸收下降率分别为164.11%,74.61%,55.16%和46.60%。由此可见,随水稻品种抗性水平的下降,接种褐飞虱后,水稻根部对水培液营养元素吸收下降程度愈显著。本研究结果可对深入阐明不同抗性水平水稻抗（耐）虫机制与根系吸收能力关系提供参考。     

褐飞虱侵害对水稻叶片、根SOD活性及丙二醛含量的影响

以分蘖期水稻协优963、TN1为供试材料,研究褐飞虱Nilaparvata lugens(St(a)l)侵害后水稻叶片、根超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量变化情况.结果表明:协优963、TN1叶片SOD活性变化不明显;15和30头/株侵害协优963后3、6、9d根SOD活性分别显著下降了88.4%和7...     

褐飞虱侵害后不同水稻品种根及地上部氮、磷、钾含量的变化

利用浓硫酸-过氧化氢消煮法,研究了不同耐、感虫品种水稻分蘖期在褐飞虱侵害胁迫后根及地上部间营养成分含量的变化情况。结果表明：褐飞虱侵害协优963后3天,根及地上部N、P、K含量、6天根及地上部N含量、9天地上部N含量在60、120头/株侵害后变化不明显;6天根及地上部P含量、6天根K含量、9天地上部P含量、9天根及地上部K含量在120头/株侵害后显著下降,60头/株侵害后变化不明显;6天地上部K含量、9天根N含量在60、120头/株侵害后均显著下降。对于协优63,3天地上部N含量、3天根及地上部P含量、6天及9天地上部N、P含量在60、120头/株侵害后变化不明显;6天根N、P含量、根及地上部K含量、9天根N含量在120头/株侵害后显著下降,60头/株侵害后下降不明显;3天、9天根及地上部K含量、9天根部P含量在60、120头/株侵害后均显著下降。表明不同水稻品种体内不同营养物质含量在褐飞虱侵害后变化不同,协优63较协优963敏感;K含量变化最明显,其次为P,最后为N;而且根比地上部对褐飞虱的反应敏感。     

褐飞虱对水稻苗期生长及地下部土壤活性碳氮的影响

地上部植食者对地下部土壤生态系统的影响引起了陆地生态学者的浓厚兴趣。报道了盆栽条件下褐飞虱取食不同品种水稻后对水稻苗期生长和土壤活性碳氮的影响。土壤活性碳氮水平的评价采用了土壤微生物生物量碳和氮、可溶性碳和氮及无机氮等指标,它们是反映土壤生态过程的重要变量。结果表明,褐飞虱侵害降低了苗期水稻茎叶、根系的生物量及根冠比,并与水稻品种的抗褐飞虱能力存在交互作用。褐飞虱也显著影响土壤活性碳氮水平(P0.05),并强烈依赖于水稻品种特性。一般的,褐飞虱导致感虫品种广四的土壤微生物生物量碳、可溶性碳下降,而对抗虫品种IR36的影响则相反。在褐飞虱的危害下,抗虫品种水稻对土壤微生物生物量氮、可溶性氮及硝态氮的促进程度较大。中感品种汕优63与汕优559在褐飞虱作用下对水稻茎叶、根系生物量及土壤活性碳氮的影响也不相同。汕优63的影响趋势与感虫品种广四一致,而汕优559的影响与抗虫品种IR36更接近。总之,土壤活性碳氮组分对褐飞虱危害的响应程度和趋势因水稻品种不同而不同,特别是抗虫品种在褐飞虱侵害时有利于土壤活性碳氮水平的维持,提高土壤生物活性,从而可能进一步促进土壤生态功能的发挥。     

褐飞虱为害对不同抗性水稻品种苗期根系几种营养物质和总酚含量的影响

本文以对褐飞虱Nilaparvata lugens(St?l)具不同抗性水平的水稻品种为研究对象,通过在苗期接入不同密度褐飞虱后测定水稻根系可溶性糖、游离氨基酸、可溶性蛋白质和总酚变化情况,以明确水稻抗虫性与根系生理生化物质含量的关系.研究结果表明,根系中的可溶性糖除了苗龄8d不接虫的处理,其余处理均以感虫品种TN1含量最高,显著高于3个抗虫品种IR36、Rathu-Heenati(RHT)、Ptb33.各苗龄不同接虫密度TN1根系游离氨基酸及可溶性蛋白质含量均显著高于3个抗虫品种.各苗龄不同接虫密度TN1根系总酚含量均显著低于3个抗虫品种,以Ptb33总酚含量最高,各处理均显著高于IR36及RHT.结果可为进一步开发利用根系指标优良的抗性水稻品种提供科学依据.     

不同抗、感水稻品种对褐飞虱肠道菌群的影响

本研究旨在探究取食不同抗性水稻品种对褐飞虱肠道菌群多样性及丰度的影响。将生长一致的3龄褐飞虱若虫分别置于高抗水稻品种RHT、高感水稻品种TN1以及中等抗性水稻品种ZH11,取食1 d和3 d后,分别对褐飞虱肠道进行取样,提取总DNA并通过HiSeq 2500平台对肠道细菌16S rRNA-V4区进行测序。对测序结果进行分析,统计不同样本中肠道微生物操作分类单元(operational taxonomic unit,OTU)数量,并在不同等级的分类阶元上统计细菌组成、丰度及Alpha多样性。对取食3种不同抗性水稻品种的褐飞虱肠道菌群特有及共有OTUs进行统计,并对丰度较高及显著差异菌群进行统计分析。褐飞虱每个肠道样本获得70000余条有效序列,根据序列相似性聚类成一定数目的OTUs。褐飞虱分别取食RHT、TN1、ZH11水稻1 d后的样本中,共有的OTUs数目为213个,特有的OTUs数目分别为424、77和130个。取食3 d后的样本中,共有的OTUs数目为217个,特有的OTUs数目分别为140、162和63个。对不同菌群含量进行分析发现,不动杆菌属Acinetobacter及沃尔巴克氏体属Wolbachia是含量较高的两类优势菌,其中不动杆菌属在取食RHT的褐飞虱肠道中的含量低于取食TN1及ZH11的褐飞虱肠道中的含量。同时,对319个属的细菌物种在分别取食RHT,TN1和ZH11的褐飞虱样本中的含量进行分析,发现了8类差异显著的物种。褐飞虱能够通过改变肠道细菌组成响应不同抗性水稻品种。研究结果为进一步挖掘褐飞虱体内肠道菌群在响应水稻抗性过程以及开发基于微生物资源进行褐飞虱防控提供参考。     

水稻品种对褐飞虱的田间抗性及其生态学机制

评价了7个水稻品种(浙粳22、宜香845、中组14、秀水123、二优倍九、感虫对照品种TN1和抗虫对照品种IR36)在田间成株期对褐飞虱Nilaparvata lugens(Stl)的抗性表现,并初步分析了它们的抗性机制。结果表明,在田间网室人工诱发条件下,浙粳22、宜香845、秀水123和中组14等4个品种的抗性水平与抗虫品种IR36相同,均小于3级,表现为抗虫,而二优培九则与感虫品种TN1相同,表现为感虫。在自然发生条件下的水稻分蘖期至乳熟期,宜香845和中组14上褐飞虱数量仅为TN1上的7.84%～24.44%,秀水123和浙粳22则为TN1上的30.19%～60.27%。在4个抗性品种上褐飞虱的产卵量和卵孵化率明显减少,而若虫存活率仅为TN1上的20%～30%。与IR36相同,4个抗性品种上褐飞虱的若虫存活率和种群增长倍数均显著低于TN1上,说明他们对褐飞虱的抗性主要表现为抗生性。     

抗感水稻品种受灰飞虱为害后的生理反应差异

灰飞虱Laodelphax striatellus Fallén(SPBH)是我国水稻生产上的一种重要害虫。为探明水稻抗灰飞虱的生理基础,在不同灰飞虱虫口密度(0、5、10、20头/株)及不同为害时间(3 d、6 d)下,检测了抗感水稻品种相关生理指标的变化差异。结果表明,灰飞虱为害后,抗感水稻植株中叶绿素、可溶性糖及可溶性蛋白含量均呈下降趋势,感虫品种中的下降幅度显著大于抗虫品种,且感虫品种的叶绿素、可溶性糖及可溶性蛋白含量在不同虫口密度及不同为害时间下,均存在显著差异。当灰飞虱以20头/株为害6 d后,武育粳3号、Kinmaze、DV85和Mudgo中叶绿素下降幅度分别为46.0%、46.0%、2.3%和2.1%,可溶性糖含量下降幅度分别为55.5%、46.3%、9.2%和11.7%,可溶性蛋白含量下降幅度分别为22.3%、29.5%、8.5%和6.7%。抗感水稻中过氧化物酶活性随虫量增大和为害时间延长而显著升高,过氧化氢酶活性则随虫量增加和为害时间延长而降低,但抗虫植株中保护性酶活性对虫害胁迫的响应明显早于感虫材料。游离脯氨酸和丙二醛含量均随着灰飞虱虫量增大及为害时间延长而上升,其中,游离脯氨酸在抗虫材料中的上升幅度高于感虫品种,丙二醛含量则在感虫品种的上升幅度显著高于抗虫材料。     

Physiological responses to Nilaparvata lugens in susceptible and resistant rice varieties: allocation of assimilates between shoots and roots

Nilaparvata lugens (St?l) is a typical vascular feeder, primarily sucking the phloem sap of host plants. Its feeding on rice, Oryza sativa L., plants changes the pattern of allocation of assimilates between roots and shoots, and the root:shoot (R/S) ratio of assimilates is often measured as an index of physiological responses to N. lugens. The current study investigated changes in the R/S ratio of biomass, sucrose, and soluble sugar contents of rice plants in a susceptible variety (TN1) and a resistant variety (Xieyou 963). The results demonstrated that root and shoot biomasses in the two varieties linearly decreased with the increase of N. lugens infestation density. However, the relationship between changes in the R/ S ratio ofbiomass and N. lugens density differed between rice varieties, with the R/S increasing with infestation density in TN1 and decreasing in Xieyou 963. Sucrose and soluble sugar contents and their R/S values were also significantly different between the two varieties. Compared with the control that was not infested by N. lugens, the R/S values of sucrose and soluble sugar at 3 days after infestation (DAI) increased but decreased at 6 DAI in TN1. The R/S values of sucrose and soluble sugar were higher at 6 DAI than those at 3 DAI in TN1, whereas these values were lower at 6 DAI than at 3 DAI in Xieyou 963. These contrasting results suggest that physiological responses to N. lugens infestation differ between the susceptible and tolerant rice varieties.     

Changes of zeatin riboside content in rice plants due to infestation by Nilaparvata lugens (Homoptera: Delphacidae)

The effect of Nilaparvata lugens (St?l) (Homoptera: Delphacidae), infestation on the content of zeatin ribosides (ZR) in rice plants was investigated with enzyme-linked immunosorbent assay. Hydroponics experiments were conducted on 'Zhendao 2' rice, in which plants were subjected to N. lugens infestation at three nonhopperburn-causing densities (15, 30, and 60 nymphs per hill) for 2, 4, 6, and 8 d and at one hopperburn-causing density (240 nymphs per hill) for 2, 4, and 6 d, respectively. When rice plants were infested at the nonhopperburn-causing densities, ZR content in leaves varied significantly with the infestation density. Compared with the control plants, ZR content in rice leaves decreased significantly after infestation by 60 nymphs per hill for 2 d, but it tended to increase due to prolonged infestation at all the nonhopperburn-causing densities. In contrast, ZR content in rice roots significantly reduced after the plants being infested at the density of 15 nymphs for 2 d and at all densities for prolonged duration, except for the plants infested by 60 nymphs for 6 and 8 d, in which the ZR content increased or did not change significantly. However, infestation at the hopperburn-causing density caused significant reduction in ZR content in rice roots, regardless of infestation duration, and in rice leaves from the plants subjected to 2-d infestation. These results are discussed in relation to the possible physiological reaction of rice plants to N. lugens infestation and the resultant severe damage or hopperburn.     

Role of abscisic acid in cadmium tolerance of rice (Oryza sativa L.) seedlings

Changes in abscisic acid (ABA) contents in Cd-treated rice (Oryza sativa L.) seedlings of two cultivars were investigated. On treatment with CdCl2, the ABA content rapidly increased in the leaves and roots of Cd-tolerant cultivar (cv. Tainung 67, TNG67) but not in the Cd-sensitive cultivar (cv. Taichung Native 1, TN1). The reduction of transpiration rate of TN1 caused by Cd was less than that of TNG67. Exogenous application of ABA reduced transpiration rate, decreased Cd content, and enhanced Cd tolerance of TN1 seedlings. Exogenous application of the ABA biosynthesis inhibitor, fluridone, reduced ABA accumulation, increased transpiration rate and Cd content, and decreased Cd tolerance of TNG67 seedlings. Fluridone effect on Cd toxicity of TNG67 seedlings was reversed by the application of ABA. The roles of endogenous ABA in Cd tolerance of rice seedlings are discussed and suggested.     

Post-anthesis development of inferior and superior spikelets in rice in relation to abscisic acid and ethylene

The purpose of this study was to test the hypothesis that the interaction between abscisic acid (ABA) and ethylene may be involved in mediating the post-anthesis development of spikelets in rice (Oryza sativa L.). Two rice genotypes were field-grown, and the changes of ABA, ethylene, and 1-aminocylopropane-1-carboxylic acid (ACC) levels in spikelets during grain filling and their relationships with endosperm-division and grain-filling rates were investigated. The results showed that earlier-flowering superior spikelets exerted dominance over later-flowering inferior spikelets in endosperm cell-division and grain-filling rates. The two genotypes behaved the same. Later-flowering spikelets had higher levels of ethylene and ACC than earlier-flowering spikelets. The ethylene evolution rate was significantly and negatively correlated with the cell division and grain filling rates. By contrast to ethylene, later-flowering spikelets contained a lower ABA content/concentration and showed a low content ratio of ABA to ACC than earlier-flowering ones. The cell-division and grain-filling rates were significantly and positively correlated with both ABA contents and the ratio of ABA to ACC. Application of cobalt ion (inhibitor of ethylene synthesis) or ABA at an early grain-filling stage significantly increased endosperm cell division rate and cell number, grain-filling rate, and grain weight of inferior spikelets. Application of ethephon (an ethylene-releasing agent) or fluridone (an inhibitor of carotenoid synthesis) had the opposite effect. The results suggest that antagonistic interactions between ABA and ethylene mediate endosperm cell-division and grain-filling in rice. A higher ratio of ABA to ethylene in rice spikelets is required to maintain a faster grain-filling rate.     

Regulation of leaf senescence, grain-filling and yield of rice by kinetin and abscisic acid

Senescence of rice ( Oryza sativa L. cv. Jaya) leaves was regulated with kinetin and abscisic acid (ABA) sprays at the reproductive stage. The effect of such sprays on grain-filling and yield was analyzed. Spraying 100-day-old plants with kinetin solution (100 μg ml^-1) significantly delayed senescence as indicated by higher total chlorophyll and protein levels in the three uppermost leaves compared with the controls. In contrast, spraying with ABA (15 μg ml^-1) significantly promoted foliar senescence. The number of spikelets per panicle, number of panicles, percentage filled grains, panicle weight and grain yield per plant and the mobilization and harvest indices were significantly increased by kinetin treatment, while ABA decreased most of them. The possibility of increased grain-filling and thus, yield due to delayed foliar senescence by kinetin treatment and decreased grain-filling due to hastening of senescence by ABA is discussed.