盐分和母树大小对黑松海防林种子萌发和幼苗早期生长的影响

研究了盐度(0、0.02、0.04和0.08 mol·L~(-1))和黑松母树大小对山东半岛北部海防林的主要造林树种黑松种子萌发和幼苗早期生长的影响.结果表明:盐度对黑松种子的发芽率有显著影响,随着NaCl浓度的升高,种子萌发率逐渐下降;盐分抑制黑松幼苗的早期生长,随着盐浓度升高,黑松幼苗的根长、芽长及根干质量均显著降低;母树大小在总体上对种子萌发率没有影响,但显著影响黑松幼苗的根长、芽长和芽干质量;盐度和母树大小的相互作用显著影响黑松幼苗的根长和芽长.而对黑松种子萌发率、幼苗根干质量和芽干质量的影响不显著.

Abstract：

Pinus thunbergii is the main forestation tree species of coastal protection forests in northern Shandong Peninsula of China. Its seed germination and seedling early growth were stud-ied under the conditions of different water salinity (0, 0. 02, 0. 04, and 0. 08 mol·L~(-1)) and mother tree sizes. With increasing sea water salinity, the seed germination rate, root-and plu-mule length, and the dry weights of root and plumule decreased significantly. Mother tree size had little effects on the seed germination rate, but affected the root-and plumule length and the plumule dry weight significantly. The interaction of sea water salinity and mother tree size affect-ed the root-and plumule length significantly, but less affected the germination rate and the dry weights of root and plumule.     

Promotion by 5-Aminolevulinic Acid of Germination of Pakchoi （Brassica campestris ssp. chinensis var. communis Tsen et Lee） Seeds Under Salt Stress

The seed germination and seedling growth of pakchoi （Brassica campestris ssp. chinensis var. communis Tsen et Lee cv. Hanxiao） were not significantly inhibited until the concentration of NaCl was increased to 150 mmol/L. Treatment of pakchoi seeds with exogenous 5-aminolevulinic acid （ALA）, at concentrations ranging from 0.01 to 10.00 mg/L, promoted seed germination when seeds were stressed by salinity, whereas levulinic acid （LA）, an inhibitor of ALA dehydrase, significantly inhibited seed germination and seedling growth, suggesting that metabolism of ALA into porphyrin compounds was necessary for seed germination and seedling growth. Determination of respiratory rate during seed germination showed that ALA increased seed respiration under both normal conditions and salt stress. Furthermore, salt stress decreased levels of endogenous ALA, as well as heme, in etiolated seedlings. More salt-tolerant cultivars of pakchoi contained higher relative levels of endogenous ALA and heme under conditions of salt stress. These results indicate that salt stress may inhibit the biosynthesis of endogenous ALA and then heme, which is necessary for seed germination, and treatment of seeds with exogenous ALA prior to germination may be associated with the biosynthesis of heme.     

Comparative Studies on the Allelopathic Effects of Ulva pertusa Kjellml, Corllina pilulifera Postl et Ruprl, and Sargassum thunbergii mertl O. Kuntze on Skeletonema costatum （Grev.）Cleve

In the present study, we evaluated the allelopathic effects of three macroalgae, namely Ulva pertusa Kjellml, Corallina pilufifera Postl et Ruprl, and Sargassum thunbergii Mertl O. Kuntze, on the growth of the microalga Skeletonema costaturn （Grev.） Creve using culture systems in which the algae coexisted. The effects of the macroalgal culture medium filtrate on S. costatum were also investigated. Moreover, isolated co-culture systems were built to confirm the existence of allelochemicals and preclude growth inhibition by direct contact. The coexistence assay data demonstrated that the growth of S. costaturn was strongly inhibited when fresh tissues, dry powder and aqueous extracts were used; the allelochemicals were lethal to S. costatum at relatively higher concentrations. The effects of the macroalgal culture medium filtrate on the microalga showed both species specificity and complexity. The inhibitory effect of fresh macroalgal tissue and culture medium filtrate on the microalga was due to the alleochemicals released by the macroalgae. The results of the present study show that the allelopathic effects of macroalgae on the microalga are complex. The present study could shed light onto the basis of the interaction between macro- and microalgae.     

EFFECTS OF SEEDING DENSITY AND BASIC MANURE ON THE GROWTH OF DRY NURSERY SEEDLINGS IN LATE DOUBLE CROPPING RICE IN SOUTH CHINA

During the period of dry nursery seedling raising of late double cropping indica rice in South China, both chemical fertilizer and farmyard manure did not show obvious effect on the growth of shoot and root in young seedlings at 4-leaf stage (18-day-old seedling), but had significant effects on root growth in old seedlings with 6-7 leaves (27-day-old seedling) at suitable seeding densities (65-125g m~(-2)). There were satistically significant differences (at 0.01 or 0.05 levels)between treatments in root number and rooting ability of root-pruned seedlings.     

Response of transgenic potato seedlings to allelopathic pressure and the effect of nutrients in the culture medium

Chinese farmers frequently use a wheat–potato cropping system. The land area planted to transgenic potatoes is increasing because transgenic potatoes have greater resistance to pests and diseases. However, little is known about the bio-compatibility of transgenic potatoes with wheat straw. The objective of this tissue culture study was to determine the allelopathic effects of wheat straw on transgenic potato seedlings. Seedlings were cultured on normal MS medium (normal treatment) and nutrient-deficient MS medium (acclimated treatment) and then transferred to MS medium, which contained wheat straw powder. Wheat straw powder inhibited potato seedling growth in both treatments. Among the parameters analyzed in this study, inhibition was greatest for plant fresh weight and least for plant height. The inhibitive effects of wheat straw were greater for seedling roots compared to shoots. Resistance to allelopathic pressure from wheat straw was greater in acclimated seedlings compared to normal seedlings. This suggested that previous pressure may have induced tolerance in the transgenic potato seedlings. Furthermore, growth inhibition of potato seedlings from the normal treatment increased as the amount of wheat straw powder in the culture medium increased. Calculations indicated that the presence of wheat straw would lead to a 55% reduction in the total biomass of normal potato seedlings compared to a 39% reduction for acclimated seedlings. Parameters such as net photosynthesis rate (Pn) and quantum yield (Y(II)) changed as the nutrient content of the culture medium increased or decreased, but the changes in the parameters were smaller for acclimated seedlings compared to normal seedlings. This suggests that nutrient status during the culture period could help transgenic potato seedlings adapt and compensate for energy loss from seedlings in defending against allelopathic pressure. In summary, the results show that previous exposure to pressures such as nutrient deficiency may increase the allelopathic pressure resistance of transgenic potato seedlings.     

Response of transgenic potato seedlings to allelopathic pressure and the effect of nutrients in the culture medium

Chinese farmers frequently use a wheat–potato cropping system. The land area planted to transgenic potatoes is increasing because transgenic potatoes have greater resistance to pests and diseases. However, little is known about the bio-compatibility of transgenic potatoes with wheat straw. The objective of this tissue culture study was to determine the allelopathic effects of wheat straw on transgenic potato seedlings. Seedlings were cultured on normal MS medium (normal treatment) and nutrient-deficient MS medium (acclimated treatment) and then transferred to MS medium, which contained wheat straw powder. Wheat straw powder inhibited potato seedling growth in both treatments. Among the parameters analyzed in this study, inhibition was greatest for plant fresh weight and least for plant height. The inhibitive effects of wheat straw were greater for seedling roots compared to shoots. Resistance to allelopathic pressure from wheat straw was greater in acclimated seedlings compared to normal seedlings. This suggested that previous pressure may have induced tolerance in the transgenic potato seedlings. Furthermore, growth inhibition of potato seedlings from the normal treatment increased as the amount of wheat straw powder in the culture medium increased. Calculations indicated that the presence of wheat straw would lead to a 55% reduction in the total biomass of normal potato seedlings compared to a 39% reduction for acclimated seedlings. Parameters such as net photosynthesis rate (Pn) and quantum yield (Y(II)) changed as the nutrient content of the culture medium increased or decreased, but the changes in the parameters were smaller for acclimated seedlings compared to normal seedlings. This suggests that nutrient status during the culture period could help transgenic potato seedlings adapt and compensate for energy loss from seedlings in defending against allelopathic pressure. In summary, the results show that previous exposure to pressures such as nutrient deficiency may increase the allelopathic pressure resistance of transgenic potato seedlings.     

乡土树种茶梨种子萌发特性及其对人工繁育的启示

本试验研究了中国南方优良的乡土树种茶梨(Anneslea fragrans)种子在假种皮有无、不同脱水水平、PEG渗透胁迫和不同温度、光照条件下的萌发特性.结果表明:假种皮的存在抑制了茶梨种子的正常萌发;新鲜种子含水量较高(65.6%),脱水对于种子萌发特征具有显著影响,随着在干燥剂硅胶中脱水时间的增加,种子萌发率和发芽势持续降低,在经过48 h的持续脱水后种子完全丧失萌发能力,表明茶梨种子属于顽拗性种子;种子萌发对PEG渗透胁迫较敏感,其萌发率和发芽势随着PEG胁迫浓度的增加而降低;茶梨种子萌发对光照并不敏感,其萌发的最适温度范围是20℃～25℃,高温会抑制种子萌发.基于种子萌发对不同生态因子的响应,提出了该物种人工繁育的合理建议.

Abstract：

This paper studied the seed germination characteristics of native species Anneslea fra-grans in Southern China under the conditions of aril removal, dehydration, PEG osmotic stress, and different light and temperature. Aril removal benefited the seed germination of A. fragrans. Fresh-harvested seeds had higher moisture content (65.6%), and dehydration gave significant impact on their germination. The germination rate decreased with increasing dehydration dura-tion, and the seed viability was completely lost after 48 h continuous dehydration. Soaking in 5% -30% PEG solution for 24 h decreased the seed germination rate significantly, indicating that A. fragrans seed germination was sensitive to osmotic stress. Light had little effects on the seed germination. The optimal temperature range for the seed germination was 20 ℃～25℃, while high temperature inhibited the seed germination. Based on the responses of the seed germination to the test factors, some suggestions were made on the artificial propagation of A. fragrans.     

Red Radiation and Choline Compounds Influence Growth and Greening of Wheat Seedlings

The effects of 2-chloroethyltrimethylammonium chloride (CCh), 2-ethyltrimethylammonium chloride (Ch), and acetylcholine chloride (ACh) at concentrations of 1 μM - 5 mM and of red radiation (R) pulse on growth, greening, and formation of the photosynthetic apparatus in etiolated wheat seedlings (Triticum aestivum L. cv. Moskovskaya-35) were examined. A short-term application of cholines and R pulse stimulated the first leaf growth and its appearance from coleoptile, and inhibited the coleoptile growth. The effects of cholines were observed during 96 h after the treatment of 4-d-old seedlings and depended on the type and the concentration of cholines. CCh, Ch, and R were also stimulators of greening and increased the photosynthetic activity, whereas ACh did not influence the process of greening. Joint effects of R with cholines on the growth and photomorphogenesis were greater than the individual ones, whereas far-red (FR) radiation decreased the influence of cholines. Thus phytochrome may modify the effects of cholines in the processes of growth and greening. This revised version was published online in June 2006 with corrections to the Cover Date.     

Presowing Seed Treatment with Cytokinins and Its Effect on Growth, Photosynthetic Rate, Ionic Levels and Yield of Two Wheat Cultivars Differing in Salt Tolerance

The effects of presowing seed treatment with different concentrations of cytokinins （kinetin and benzylaminopurine; 100, 150, and 200 mg/L） on growth, photosynthetic capacity, and ion homeostasis were investigated in two spring wheat （Triticum aestivum L.） cultivars, namely MH-97 （salt sensitive） and Inqlab- 91 （salt tolerant）. Primed and non-primed seeds were sown in a field in which NaC1 salinity of 15 dS/m was developed. Of the different concentrations of priming agents tested, the effect of a moderate concentration of kinetin （150 mg/L） was very pronounced, particularly in improving growth and grain yield, in both cultivars. In addition, priming with kinetin alleviated the adverse effect of salt stress on gaseous exchange characteristics （net CO2 assimilation rate and water use efficiency） in both cultivars. Seed priming with a moderate concentration of kinetin also altered the pattern of accumulation of Na^＋ and Clˉ in the shoots, irrespective of the wheat cultivar, under conditions of salt stress. However, all other priming agents at the different concentrations tested did not show any consistent effect on ion levels, except hydropriming, which increased K^＋ levels in the shoots of both cultivars under salt stress. In conclusion, a moderate concentration of kinetin showed a consistent effect in altering the growth and grain yield of both wheat cultivars, which was related to the beneficial effects of kinetin priming on water use efficiency and photosynthetic rate under conditions of salt stress.     

Joint effects of acetochlor and urea on germinating characteristics of crop seeds

In order to evaluate ecological risk of agrochemicals in common use, joint toxic effects of acetochlor and urea on germinating characteristics of Chinese cabbage (Brassica Pe-kinensis Rupr) seeds were investigated using the water-culture method and the soil-culture method. The results indicated(that excessive application of acetochlor and urea, when the concentrations were higher than 31.3 mg ·kg-1 for acetochlor and 500 mg ·kg-1 for urea, had strong inhibitory effects on the rate of seed germination, root elongation and hypocotyl length of Chinese cabbage. The inhibitory rate of the germinating characteristics of Chinese cabbage seeds was significantly increased with an increase in the concentration of acetochlor or urea. The two agrochemicals in water had a stronger toxicity than these in the soil at the same concentration. Among the three indexes, hypocotyl length was the most sensitive to the toxicity of acetochlor and urea.     

茄子自毒物质对辣椒种子萌发及枯萎菌的化感效应

运用模拟的方式,采用生物测定和室内培养的方法,研究了两种茄子自毒物质香草醛和肉桂酸各浓度对辣椒种子萌发和幼苗生长的化感效应,及其对辣椒枯萎菌菌丝生长的影响.结果表明:这两种自毒物质对辣椒种子萌发和幼苗生长具有低浓度促进,高浓度抑制的化感效应.香草醛和肉桂酸对辣椒和茄子种子的化感效应存在较大差异,辣椒种子受这两种自毒物质的抑制强度明显弱于茄子种子.香草醛和肉桂酸对辣椒枯萎菌菌丝生长表现为各浓度(0.1, 0.5, 1, 4mmol/L)下均具有抑制作用,作用强度随着浓度增加而增强,肉桂酸低浓度时对菌丝生长的抑制作用即达到显著水平.     

大蒜根系分泌物的化感作用

以苍山白蒜和蔡家坡紫蒜为材料,采用水培方法收集根系分泌物,研究了2个大蒜品种的根系分泌物对莴苣种子发芽和幼苗生长及对黄瓜枯萎病菌、西瓜枯萎病菌的化感效应.结果表明:2个大蒜品种的根系分泌物对莴苣种子发芽和幼苗生长均表现为低浓度(0.1、0.2 g·mL-1)促进、高浓度(0.4、0.6 g·mL-1)抑制,高浓度时蔡家坡紫蒜的抑制作用大于苍山白蒜;对黄瓜枯萎病菌和西瓜枯萎病菌的菌丝生长及孢子萌发均表现为抑制作用,随着根系分泌物浓度的提高,抑制作用增强,其中黄瓜枯萎病菌较敏感,且蔡家坡紫蒜的抑制作用大于苍山白蒜.     

碎米莎草穗部总生物碱化感活性和抑菌效果的研究

以种子萌发率、幼苗根长、幼苗株高和单株鲜质量以及菌落直径为指标,对碎米莎草(Cyperus iria L. )穗部总生物碱的化感活性及抑菌效果进行了初步研究.结果表明,不同质量浓度的总生物碱溶液对6种供试植物的种子萌发和幼苗生长均有不同程度的影响;质量浓度为500～4 000 mg·L~(-1)的总生物碱溶液对水稻(Oryza sativa L. )种子萌发率和幼苗的株高和单株鲜质量无显著影响(P>0.05),但4 000 mg·L~(-1)总生物碱溶液对水稻幼苗的根长有显著的抑制作用(P<0.05);总生物碱溶液对烟草(Nicotiana tabacum L. )、鳢肠[Eclipta prostrata (L. ) L. ]、千金子[Leptochloa chinensis (L. ) Nees]、三叶鬼针草(Bidens pilosa L. )及丁香蓼(Ludwigia prostrata Roxb. )的种子萌发和幼苗生长的抑制作用随质量浓度的提高而增强,且当质量浓度达到4 000 mg·L~(-1)时, 种子萌发率和幼苗的根长、株高和单株鲜质量均最低, 与对照差异显著(P<0.05). 碎米莎草穗部总生物碱溶液对6种供试植物病原真菌的抑菌效果有一定的差异, 但总体上随质量浓度(25～400 mg·L~(-1))的提高抑菌效果逐渐增强;当质量浓度达到400 mg·L~(-1)时,总生物碱溶液对苹果轮纹病病菌(Physalospora piricola Nose)、油菜菌核病病菌[Sclerotinia sclerotiorum (Lib. ) de Bary]、水稻稻瘟病病菌[Magnaporthe grisea (Hebert) Barr. ]、小麦赤霉病病菌(Fusarium graminearum Schw. )和番茄早疫病病菌(Alternaria solani Jones et Grout. )的抑菌率最高,分别达到74.05%、64.73%、43.54%、35.09%和32.56%,与对照差异显著(P<0.05);但25～400 mg·L~(-1)总生物碱溶液对杨树溃疡病病菌(Dothiorella gregaria Sacc. )无显著的抑菌作用(P>0.05).研究结果显示,碎米莎草穗部总生物碱具有被开发为稻田用生物源农药的潜力.     

侧柏不同器官水提取物对油松种子萌发和幼苗生长的他感效应

研究了侧柏（Platycladus orientalis）根、枝、叶、果实不同浓度水提取物及枝叶挥发油对油松种子萌发和幼苗生长的他感效应。结果表明：侧柏各器官及挥发油都含有化感物质,均对油松种子萌发及幼苗生长表现出“高抑低促”效应,而且低浓度时的促进作用明显强于高浓度时的抑制作用。与对照相比,在浓度为2 mg·mL^-1时,侧柏根水提取物对油松幼苗根长和鲜重的促进能力最强,其根长和鲜重分别比对照提高了79.78%和376.60%;侧柏叶水提取物对油松幼苗苗高促进能力最强,比对照提高了102.41%;侧柏枝水提取物对油松种子发芽的促进能力最强,发芽率比对照提高了65.63%。而在浓度为30 mg·mL^-1时,除了侧柏根和枝水提取物对油松种子萌发（87.50%）和鲜重（85.11%）表现出明显的抑制作用外,其它提取物对油松幼苗根长和苗高生长的抑制作用均不明显。侧柏枝叶挥发油对油松种子萌发,幼苗生长均表现为促进作用,特别对油松种子萌发具有显著的促进作用,其促进率达70.37%。说明侧柏和油松混交,可能有利于油松树木生长及生产力的提高。     

珙桐—灯台树枝和叶的水提物对白菜种子萌发和幼苗生长的化感效应

为了证实珙桐（Davidia involucrata）及其伴生树种灯台树（Bothrocaryum controversum）是否会通过化感作用影响其他植物的种子萌发和幼苗生长,以维持二者长期稳定的伴生关系,本研究以平武县野生珙桐及灯台树的枝、叶水提液为材料来源,以白菜（Brassica pekinensi）的种子为受体,探究2种植物的枝、叶及其混合后的5种质量浓度（0、0.025、0.050、0.075、0.100 g·mL^-1）水提液对白菜的种子萌发和幼苗生长的影响,结果表明：①珙桐和灯台树的枝水提液对白菜种子萌发影响较小,对幼苗生长有显著促进作用且随质量浓度增加而增大（P＜0.05）。②珙桐和灯台树的叶水提液对白菜种子萌发均具有显著抑制作用（P＜0.05）,但对幼苗生长的影响各不相同。前者呈现随质量浓度增加的“低促高抑”现象,而后者呈现随质量浓度增加“抑制增加”的特点。③不同来源的枝—叶混合的水提液对白菜种子萌发均表现出显著的抑制作用（P＜0.05）,但对幼苗生长均随质量浓度增加表现出“低促高抑”特点。上述结果证实了珙桐和灯台树枝、叶水提液对同一受体植物的种子萌发和幼苗生长的化感作用确实存在差异,树种、部位和质量浓度不同均会导致化感作用的强度和方向不同。这种现象可能是植物在群落中为了维持稳定的种间关系而长期进化的结果。     

连作大豆根分泌物对根腐病病原菌的化感作用

采用砂培,水培和室内培养等试验方法研究了连作大豆根分泌物对根腐病病原菌的化感作用。结果表明,与对照相比,连作和轮作大豆根分泌物对半镰孢菌,粉红粘帚功和尖镰孢菌尤其是对半裸镰孢菌的生长有明显的化感促进作用,差异达显著或极显著水平,低浓度时,连作大豆根分泌物对半裸镰孢菌和粉红粘帚菌生长的化感促进作用明显大于轮作大豆,差异达显著水平,同一茬口,高浓度根分泌物半裸镰孢菌生长的化感促进作用小于低浓度,而且在连作大豆中差异达显著水平。与对照相比,高浓度的邻苯二甲酸和丙二酸（L5和B5）对半裸镰孢菌,粉红粘帚菌和尖镰孢菌尤其是对半裸镰孢菌的生长有化感抑制作用,差异达显著或极显著水平,而低浓诬的邻苯二甲酸和丙二酸对半裸镰孢菌,粉红粘帚菌和尖镰孢菌的生长有化感促进,部分差异达显著水平。     

嫁接茄子根系分泌物的化感效应

采用室内生物测定的方法,研究了不同砧木、不同浓度和不同生育期嫁接茄子根系分泌物的化感效应.结果表明,嫁接茄根系分泌物与自根茄相比,促进了茄子种子的萌发和幼苗生长.各砧木品种嫁接茄根系分泌物的化感效应显著或极显著高于对照,其中发芽率和苗高最高,增加29.1%和37.1%;不同浓度试验结果呈现“低促高抑”的规律,当浓度为0.04g·ml^-1时发芽率最高,比对照增加50%,当浓度增加到0.24g·ml^-1时,根长比对照降低了30.3%;在生长后期嫁接茄的根系分泌物对种子萌发的促进作用小于前中期,而自根茄抑制作用增强.因此,生产中使用嫁接技术是缓解由自毒作用引起的连作障碍的有效方法之一.     

辣椒根系分泌的潜力化感物质对生菜幼苗抗氧化代谢的影响

以盆栽辣椒为试验材料,采用树脂吸附萃取和气质联用仪测定辣椒根系分泌物,分析、确定其中的疑似化感物质。分别使用6种（0、2、4、8、12、16μg·mL-1）不同浓度的外源潜力化感物质处理生菜种子,通过种子发芽、幼苗生长分析其潜力化感作用,并研究其对生菜幼苗抗氧化代谢的影响。结果表明,2,6-二叔丁基苯酚（2,6-DTBP）、邻苯二甲酸二异丁酯（DIBP）和邻苯二甲酸二丁酯（DBP）为辣椒根系分泌的潜力化感物质,随三种潜力化感物质浓度的增加,生菜幼苗的谷胱甘肽（GSH）含量降低,超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）、多酚氧化酶（PPO）和抗坏血酸氧化酶（APx）活性先增加后降低。2,6．DTBP、DIBP和DBP4化感抑制作用的低限浓度分别为4、8、8pg·mL-1,三者通过降低GSH含量而损伤生菜幼苗的抗氧化代谢系统。     

辣椒疫病拮抗菌株筛选、鉴定及其防效

从疫病发病严重田块的健康辣椒植株根际分离到98株拮抗菌,从中筛选出两株具有广谱抗性并可在贫营养条件下生长良好的高效拮抗菌株HL-3和LZ-8.通过形态观察、生理生化特性和16S rDNA序列分析,确定HL-3为多粘类芽孢杆菌,LZ-8为短小芽孢杆菌.HL-3和LZ-8对辣椒疫霉菌丝生长抑制率分别为72%和68%.HL-3和LZ-8还对黄瓜枯萎病菌、辣椒枯萎病菌、棉花黄萎病菌、黄瓜立枯病菌、烟草黑胫病菌和番茄青枯病菌具有显著的抑制作用.盆栽试验表明,HL-3和LZ-8对辣椒苗期疫病防治效果分别为72%和83%,且对辣椒生长表现出明显的促生作用.     

巴茅草水浸提液对3种作物种子萌发及幼苗生长的化感作用

本文以发芽率、发芽速度指数、发芽指数、根长、茎长和生物量为种子萌发和幼苗生长参数,研究不同生长时期巴茅草叶片和茎秆水浸提液对白菜、生菜、水稻的化感作用。结果表明: 巴茅草叶水浸提液化感作用强于茎秆水浸提液,叶水浸提液处理后受体植物的发芽指数和生物量均显著低于茎水浸提液。枯萎期巴茅草的化感作用强于生长旺盛期。不同浓度巴茅草叶水浸提液对3种作物的化感作用存在明显的量效关系,浸提液浓度越高,巴茅草的化感抑制作用越强。巴茅草叶水浸提液对白菜和生菜各萌发指标100%抑制的浓度分别为0.075和0.10 g·mL^-1;而0.10 g·mL^-1巴茅草叶水浸提液对水稻发芽率、发芽速度指数、发芽指数的抑制率分别为13.8%、27.2%、19.3%。巴茅草叶水浸提液对白菜和生菜各生长指标100%抑制的浓度分别为0.05和0.10 g·mL^-1;而0.10 g·mL^-1巴茅草叶水浸提液对水稻根长、茎长、生物量的抑制率分别为64.6%、92.9%、21.8%。结合种子萌发和幼苗生长的综合化感指数,3种供试作物对巴茅草化感作用的敏感程度为白菜>生菜>水稻。