温度对不同叶龄长雄野生稻及其后代化感作用的影响

掌握温度对长雄野生稻(Oryza longistaminata)及其后代化感作用的影响,对开发利用野生种质资源的化感抗草基因具有重要意义。采用直接树脂吸收法收集不同叶龄长雄野生稻及其后代在各温度条件下的根系分泌物,并以稗草作为受体,测定其化感作用。结果表明:1)温度、叶龄和温度×叶龄对水稻化感作用的影响与其自身化感潜力正相关,且对强化感和中化感潜力水稻(OL、F1、RL159和RL169)的化感作用影响极显著,而对弱化感水稻(RD23和RL219)的化感作用影响不显著。2)供试条件下长雄野生稻及其后代根系分泌物对稗草的化感作用均为抑制作用,其中,低温不利于水稻化感潜力的发挥。15℃时,强和中化感潜力水稻在不同叶龄对稗草的苗高、根长和生物量的抑制作用最弱,化感综合效应指数也显著大于同等叶龄的高温处理。3)高温有利于水稻化感潜力的发挥,但并非总是随温度的升高而增强。在6叶期和8叶期,水稻材料OL、F1、RL159和RL169随温度的升高化感作用逐渐增强,但在2叶期和4叶期则表现为先增强后减弱,在25℃时对稗草化感作用最强。4)在15℃时,强和中等化感潜力水稻在2叶期化感作用最弱,而在其他温度条件下,其化感作用随叶龄的增加表现为先减弱后增强,在2叶期化感作用最强。研究结果显示,温度对不同叶龄的水稻化感作用具有调控作用,幼苗阶段高温有利于强和中化感潜力水稻化感作用的发挥。     

PS04菌株分泌物对化感稻苗生长及其抑草效果的影响

为了研究PS04菌株分泌物对化感稻苗生长及其抑草效果的影响,以化感稻3号和化两优78为材料,用6个不同浓度(0、1/100、1/150、1/200、1/250和1/300容积比)的PS04菌株分泌物分别对水稻进行浸种或喷施幼苗叶片处理,分别在28℃和22℃下测定其对化感稻幼苗的影响,并观测各处理的化感稻与稗草混种对稗草生长的影响。结果表明,28℃下,以1/300浓度PS04菌株分泌物溶液浸种化感稻3号和喷施化两优78叶片效果较好,既可以提高化感稻的生长,又不会影响其对稗草的抑制作用;22℃下,以1/200、1/250和1/300浓度喷施化两优78号叶片效果较好,均能促进其生长,并使与化两优78号混种的稗草存活率降低;1/100和1/250浸种以及1/250浓度PS04菌株分泌物溶液喷施叶片或者浸种+喷施叶片,均能促进化感稻3号的生长,也能够显著抑制各处理下与化感稻3号混种的稗草的生长。可见,PS04菌株分泌物溶液对化感稻苗的生长有促进作用,并能增强其对稗草的抑制效果。     

外来入侵杂草空心莲子草与本土杂草莲子草的化感作用潜力比较

为确定外来入侵杂草空心莲子草的化感作用潜力,以我国本土生长的莲子草为对照采用“三明治”生测法,测定了空心莲子草和莲子草及其不同器官对靶标莴苣和无芒稗根长和芽长的抑制率。 结果表明,空心莲子草叶片处理对莴苣和无芒稗根长的抑制率分别为81%和51%,对莴苣和无芒稗芽长的抑制率分别为49%和48%,显著高于空白对照。但与莲子草相比,差异不显著。空心莲子草根系对莴苣的根长平均抑制率为54%,显著高于茎和叶片。随着样品用量增加,空心莲子草对莴苣根长的抑制率显著提高,其50 mg叶片处理对莴苣根长的抑制率为83%,显著高于10 mg处理的54%和30 mg处理的61%。     

麦根腐平脐蠕孢和薏苡平脐蠕孢防治稻田稗草的生物活性和安全性

对分离自云南昆明感病稗草\[Echinochloa crus galli (L.) Beauv.\]上的病原真菌麦根腐平脐蠕孢（Bipolaris sorokiniana）和薏苡平脐蠕孢（Bipolaris coicis）开展了防治稗草潜力的评价。结果显示,B.sorokiniana和B.coicis两菌株培养5 d的发酵原液对稗草根长和芽长均有很高的抑制作用,根长最高抑制率分别为99.59%和95.78%, 芽长最高抑制率分别为91.14%和82.13%。两菌株对稗草离体叶片致病性的室内试验表明,菌丝体悬浮液处理5 d后稗草叶片病情指数最高可达100%。两菌株对稗草植株防效的温室试验表明, 菌丝体悬浮液处理稗草7 d后植株下部叶片出现萎蔫症状、脱落及死亡,处理21 d后稗草最高死亡率达到82.67%和80.00%。菌株对作物的安全性试验表明,麦根腐平脐蠕孢对作物的安全性显著高于薏苡平脐蠕孢。作为生防潜力菌株,麦根腐平脐蠕孢具有更大的应用潜力。     

水稻与无芒稗的竞争和化感作用

用差时播种共培法的改进方法对105份水稻、6份巴西陆稻进行了化感作用抗稗草评价。 结果表明长匡7号、P4、Kogyoku、 IR27316、 Milyang 54和巴西陆稻AJ035等材料对无芒稗有较好的化感作用。盆栽研究表明,谷梅2 号、中156对无芒稗的抑制作用显著大于对照,而化感作用材料TN1对无芒稗的抑制作用与无化感作用材料秀水63无显著差异。中156的抑制作用强与其株高有关,而谷梅2号对无芒稗的抑制作用强主要在于其本身的化感作用。随着水稻密度增加,无芒稗受抑程度加剧,化感作用水稻对稗草根部的抑制似乎要比无化感作用水稻强。TN1对无芒稗的化感作用不明显,可能是由于对不同生态的稗的作用不同之故。     

化感杂交稻田间抑制稗草能力及其杂种优势表现

以4个化感稻品系与7个不育系所配的28个化感杂交稻组合为材料,以美国强化感稻PI312777为对照,研究了化感杂交稻田间抑制稗草的能力及其杂种优势表现。结果显示,化感杂交稻田间抑制稗草的主要因素是化感作用和竞争作用,其中化感作用对其整体抑草效应的影响较大;2012年早季的抑草效果优于2011年晚季,即环境条件影响了化感杂交稻抑草作用的发挥,其中竞争作用受环境影响较大;相关性分析表明,化感杂交稻的抑草作用对存活稗草地上部分生长量的影响主要是竞争作用的结果。从稗草株高及单株干物重来看,化感稻0210所配组合的抑草能力表现出很强的超父本和竞争优势,且田间表现稳定。基于封行前抑草率和灌浆期抑草率,有14个组合在早、晚季均表现出优于相应父本以及美国强化感稻PI312777的抑草效果,显示化感杂交稻在抗草育种中具有良好的利用前景。     

中国部分稻种资源的化感控制杂草潜力评价

采用人工气候箱结合田间小区试验,从我国部分水稻种质资源中筛选获得了2份具有化感潜力的水稻品种（系）,其中我国台湾品种蚁公包幼苗对无芒稗根长影响因子RRL为0.43,其叶片水浸提液对无芒稗和莴苣根长抑制率分别达到45%和85%,在田间对无芒稗茎数和植株鲜质量的控制效果分别为22.0%和26.1%。云南品种地谷幼苗对无芒稗的植株高度影响因子RSH和植株干质量影响因子RPDW分别为0.62和0.58, 叶片水浸提液对无芒稗和莴苣根长抑制率分别达到53%和65%,在田间对无芒稗茎数和植株鲜质量的控制效果分别达到51.5%和46.1%。 蚁公包对莴苣的控制效果和地谷对无芒稗的控制效果均显著高于美国化感潜力品种PI312777。蚁公包和地谷是我国宝贵的化感潜力品种资源。     

套种牧草果园土壤浸提液对萝卜种子发芽和幼苗生长的化感效应

采用生物检测方法,探讨果园套种牧草,其土壤浸提液对萝卜种子发芽和幼苗生长的化感效应。结果表明:果园分别全园套种宽叶雀稗、百喜草、平托花生、圆叶决明4种牧草,其土壤浸提液均对受体萝卜种子萌发有抑制作用,而对受体萝卜根的生长有不同程度的促进作用;全园套种百喜草处理对受体萝卜根干重起抑制作用;全园套种百喜草、平托花生、圆叶决明处理对受体萝卜的幼苗生长和干重均起显著的促进作用,而全园套种宽叶雀稗处理则反之;全园套种百喜草、平托花生、圆叶决明3种牧草处理对受体萝卜的化感综合效应指数均大于套种宽叶雀稗处理,且前者起促进作用,而后者起抑制作用;用不同牧草区土壤浸提液进行砂培法培养的萝卜幼苗根系活力受到极显著抑制,对照处理的萝卜根系活力最强,为156.3μg·g-1·h-1,而宽叶雀稗处理区的根系活力最小,为64.3μg·g-1·h-1。     

水稻种质对稗草和莴苣的化感效应研究

用改进的叶浸提法和田间共生鉴定法,比较分析了从124份不同来源水稻种质中初步筛选的27份化感种质对稗草和莴苣的化感抑制效果。结果表明,叶浸提液对莴苣的抑制效果明显大于稗草;对稗草和莴苣根长的抑制效果大于苗高和发芽势;叶浸提液法与田间共生法对稗草的抑制效果呈显著的正相关,两种方法的鉴定结果有较高的一致性。叶浸提液对稗草发芽势的抑制指数与田间共生对稗草苗干重的抑制指数及其综合抑制指数呈极显著的正相关,认为稗草种子发芽势可作为测试水稻种质化感效应的重要指标。田间水稻苗高与叶浸提液对稗草根长的抑制指数及其综合抑制指数和田间共生对稗草苗高和苗干重的抑制指数及其综合抑制指数呈极显著的正相关,水稻苗高较高的种质较苗矮的种质表现出较强的化感效应。珍珠42、沙粘1、六月早、青团2号、红脚粘2和地谷的化感效应突出,对稗草的平均综合抑制指数分别为0.56、0.47、0.45、0.45、0.41和0.39,可作为强化感种质提供应用。     

水稻种质对稗草和莴苣的化感效应研究

用改进的叶浸提法和田间共生鉴定法，比较分析了从124份不同来源水稻种质中初步筛选的27份化感种质对稗草和莴苣的化感抑制效果。结果表明，叶浸提液对莴苣的抑制效果明显大于稗草；对稗草和莴苣根长的抑制效果大于苗高和发芽势；叶浸提液法与田间共生法对稗草的抑制效果呈显著的正相关。两种方法的鉴定结果有较高的一致性。叶浸提液对稗草发芽势的抑制指数与田间共生对稗草苗干重的抑制指数及其综合抑制指数呈极显著的正相关，认为稗草种子发芽势可作为测试水稻种质化感效应的重要指标。田间水稻苗高与叶浸提液对稗草根长的抑制指数及其综合抑制指数和田间共生对稗草苗高和苗干重的抑制指数及其综合抑制指数呈极显著的正相关。水稻苗高较高的种质较苗矮的种质表现出较强的化感效应。珍珠42、沙粘1、六月早、青团2号、红脚粘2和地谷的化感效应突出．对稗草的平均综合抑制指数分别为0．56、0．47、0．45、0．45、0．41和0.39，可作为强化感种质提供应用。     

Induced Effects of Exogenous Phenolic Acids on Allelopathy of a Wild Rice Accession (Oryza longistaminata, S37)

Four exogenous phenolic acids,including salicylic acid,fumalic acid,p-coumaric acid and p-hydroxybenzonic acid,were used to investigate the regulatory effects on allelopathy of a wild rice accession of S37(Oryza longistaminata),which is a known allelopathic rice.The four exogenous phenolic acids induced the enhancement of the allelopathic potential of wild rice S37 in target weeds though the weed-suppressive activities were low,and the inducible effects were dependent on the specific phenolic acid,concentra...     

Induced Effects of Exogenous Phenolic Acids on Allelopathy of a Wild Rice Accession （Oryza Iongistaminata, S37）

Four exogenous phenolic acids, including salicylic acid, fumalic acid, p-coumaric acid and p-hydroxybenzonic acid, were used to investigate the regulatory effects on allelopathy of a wild rice accession of S37 (Oryza longistaminata), which is a known allelopathic rice. The four exogenous phenolic acids induced the enhancement of the allelopathic potential of wild rice S37 in target weeds though the weed-suppressive activities were low, and the inducible effects were dependent on the specific phenolic acid, concentration and treatment time. After foliar application of exogenous phenolic acids, the inhibition rates for plant height, root length and fresh weight of barnyard grass (Echinochloa crus-galli) were significantly higher than those of the control. Especially at the concentration of 100 mg/L, the inhibition rates for plant height and fresh weight of barnyard grass by fumalic acid were 38.12% and 26.31% higher than those of the control, showing that fumalic acid was more effective compared with other phenolic acids in inhibiting monocotyledon weed growth. Furthermore, the weed-suppressive activity of aqueous extract from the leaves of wild rice S37 treated with exogenous phenolic acids was increased, and it peaked at 48 h after the treatment with the aqueous extract, and then gradually declined.     

Phenolic acid profiles of Chinese wheat cultivars

Phenolic acid concentrations were determined in 37 Chinese commercial winter wheat cultivars grown at a single site over two seasons, and fractions comprising free and bound types were analyzed using HPLC with measurements of individual phenolic acids in each fraction. Most of the parameters were significantly influenced by cultivar, season, and their interaction effects, with cultivar variance being predominant. Wide ranges of concentration among the 37 cultivars were observed. The average concentration of bound type was 661 μg g⁻¹ of dm, making up 97.5% of the phenolic acid determined with ferulic accounting for 70.7% of it, while free type made up only 2.5% of the phenolic acid determined with syringic accounting for 44.7% of it. Bound type was the predominant source to the grain phenolic acid concentrations determined. There were highly significant and positive correlations between bound ferulic concentration and total bound phenolic acid concentration, and between free syringic concentration and total free phenolic acid concentration. Cultivars Liangxing 66 and Zhongmai 895 were stable in concentration of components of phenolic acids across seasons, with high values of free and bound phenolic acids indicating they could be selected as parents in wheat breeding for health beneficial phenolic acid.     

镍处理下水稻酚酸和酚多聚物含量的变化与白叶枯病诱导抗性的关系

 研究了镍处理下水稻叶片中总酚、酚酸、酚多聚物积累和细胞壁结合态过氧化物酶（POD）活性的变化。镍处理导致总酚含量显著上升,检测到10种可溶性酚酸和7种结合态酚酸。镍处理下可溶性绿原酸和水杨酸含量明显上升,而它们的结合态含量变化不明显;镍处理显著提高可溶性和结合态阿魏酸的含量,显著降低可溶性丁香酸和对 香豆酸的含量,却诱导其结合态含量增加。镍处理后酚多聚物明显积累,以阿魏酸和丁香醛为底物的细胞壁结合态POD的活性显著升高。这些结果结合以前的研究提示,酚酸和酚多聚物积累参与了镍诱导的水稻对白叶枯病的抗性。     

两种十八碳二烯酸诱发水稻对稻瘟病的抗性及其防病作用

 研究了（１１Ｓ，１２Ｓ，１３Ｓ）－１１，１２，１３－三羟基０（９Ｚ，１５Ｚ）－十八碳二烯酸（Ａ）和（１１Ｒ）－羟基－１２（Ｓ），１３（Ｓ）－环氧－（９Ｚ，１５Ｚ）－十八碳二烯酸（Ｂ）的生物学活性。体外测试结果表明，这两种十八碳二烯酸对稻瘟菌菌丝生长只有轻微的抑制作用，而对分生孢子萌发则表现了较强的抑制作用，３－４叶期的水稻幼苗经这两种十八碳二烯酸诱发处理后均获得了对稻瘟病的抗性，减轻了稻瘟病的病情。用A处理后隔5 d接种稻瘟病菌，病情指数比对照降低64.8%；用B处理后隔2 d接种病菌，病情指数比对照降低69.8%。两种十八碳二烯酸均以5 μg/mL浓度诱发处理时，使水稻植株获得最大的诱导抗性。由A和B激发产生的诱导抗性对稻瘟病的防治效果均大于50%。先接种稻瘟病菌以诱发发病，而后隔5 d或10 d后喷施10 μg/mL的A或B水溶液，均可减轻稻瘟病的病情，其防治效果在44％－55％。     

Fatty Acid Composition of Three Rice Varieties Following Storage

The petroleum ether extractable lipids (PEE-L) and aqueous propan-1-ol extractable lipids (PWE-L) of three varieties of rice were determined gravimetrically and characterised by fatty acid profiles. The content of PEE-L (22·5–28·2 mg g⁻¹) was higher than that of PWE-L (7·4–11·5 mg g⁻¹) in brown rice with the situation reversed in milled rice (3·0–4·5 mg g⁻¹vs. 7·2–8·7 mg g⁻¹). The ratio of unsaturated fatty acid to saturated fatty acid was about two times higher in PEE-L than that in PWE-L for both brown and milled rice reflecting the selective complexation of saturated fatty acids. Rice storage at 37 °C resulted in some minor but statistically significant changes in the fatty acid profile. In the case of brown rice, the only notable changes were a reduction in the amounts of oleic and linoleic acids in the aqueous propan-1-ol extractable fatty acid fraction (PWE-FA) following storage at the higher temperature. Milled rice of all three varieties showed a decrease in linoleic acid content of PEE-L following storage at 37 °C for 4 and 7 months compared to storage at 4 °C. There was no change in fatty acid contents of PWE-L of milled rice when stored at 4 and 37 °C for 4 and 7 months. This implies that the PWE-L (or bound lipids) were more stable than PEE-L (or free lipids) during storage.     

脱落酸对水稻种子萌发的影响

以3种水稻种子培两优288、R402、LP04为材料,用不同浓度外源脱落酸(ABA)作浸种处理,研究其对水稻种子萌发的影响.结果表明:低浓度ABA(10mg/L)对水稻种子LP04的萌发具有促进作用,20～90mg/L的高浓度ABA对水稻种子的萌发具有明显的抑制作用.结合水稻种子萌发过程中可溶性糖含量、α-淀粉酶活性和内源植物激素等生理指标的检测结果表明,20～50mg/L的ABA能有效抑制水稻种子的萌发,可作为外源ABA在水稻种子储藏中使用的参考浓度.     

Phenolic acid profiles of Chinese wheat cultivars

Phenolic acid concentrations were determined in 37 Chinese commercial winter wheat cultivars grown at a single site over two seasons, and fractions comprising free and bound types were analyzed using HPLC with measurements of individual phenolic acids in each fraction. Most of the parameters were significantly influenced by cultivar, season, and their interaction effects, with cultivar variance being predominant. Wide ranges of concentration among the 37 cultivars were observed. The average concentration of bound type was 661 μg g⁻¹ of dm, making up 97.5% of the phenolic acid determined with ferulic accounting for 70.7% of it, while free type made up only 2.5% of the phenolic acid determined with syringic accounting for 44.7% of it. Bound type was the predominant source to the grain phenolic acid concentrations determined. There were highly significant and positive correlations between bound ferulic concentration and total bound phenolic acid concentration, and between free syringic concentration and total free phenolic acid concentration. Cultivars Liangxing 66 and Zhongmai 895 were stable in concentration of components of phenolic acids across seasons, with high values of free and bound phenolic acids indicating they could be selected as parents in wheat breeding for health beneficial phenolic acid.     

Distribution of proteins and amino acids in milled and brown rice as affected by nitrogen fertilization and genotype

A field experiment involving six japonica rice cultivars with contrasting agronomic traits and seven nitrogen (N) fertilizer treatments was performed to determine the effects of N and genotype on distribution of four kinds of grain proteins and amino acids in milled and brown rice. For brown and milled rice, albumin and globulin were controlled more by genotype than N treatments, whereas prolamin and glutelin were largely determined by N. Substantial genotypic differences in response of milled/brown (M/B) ratios of proteins to N treatments were detected. In comparison with large panicle cultivars, small panicle cultivars such as Wuyujing3 had the lower ratio and exhibited more stability under contrasting N treatments. N had significant influence on amino acid composition of brown and milled rice, with contents of the 17 amino acids measured increasing with elevated N rate. However, cysteine and methionine in brown rice and lysine and methionine in milled rice were not significantly affected by N. In addition, N had little effect on ratios of M/B for most of the amino acids.     

Identification and quantification of phenolic acids and anthocyanins as antioxidants in bran,embryo and endosperm of white,red and black rice kernels (Oryza sativa L.)

Whole rice grain comprising endosperm, embryo (or germ), and bran has potential beneficial health effects in addition to provision of nutrients. The distribution of phenolic acids and anthocyanins in endosperm, embryo, and bran of white, red, and black rice grains was investigated in this study. The total phenolic content (TPC) was highest in the bran, averaging 7.35 mg GAE/g and contributing 60%, 86% and 84% of phenolics in white, red and black rice. The average TPC of the embryo and endosperm were 2.79 and 0.11 mg GAE/g accounting for 17% and 23%, 4% and 10% and 7% and 9% in white, red and black rice, respectively. The antioxidant capacity determined using DPPH and ORAC displayed a trend similar to TPC. Free/conjugated phenolic acids in white, red and black rice bran accounted for 41%, 65% and 85% of total acids. Bound phenolic acids in rice bran accounted for 90% of total acids in whole grain. Cis-p-coumaric was detected in bound form in bran while cis-sinapic acid was detected in the free/conjugated form in embryo and bran. Cyanidin-3-O-glucoside and peonidin-3-O-glucoside were identified mainly in black rice bran as the total anthocyanins. Cyanindin-3-O-rutinoside was also detected in black rice bran.