西瓜皮水浸提物对西瓜种子萌发的影响

对西瓜皮水浸提物对西瓜种子发芽的生物学效应进行了研究。结果表明:水浸液在低浓度时对种子萌发率及其胚根的抑制作用较弱;随水浸液浓度的增加萌发数显著下降,并且显著地抑制胚根的伸长。     

伊贝母根系分泌物对其幼苗生长的自毒作用

采用生物测定的方法,研究了伊贝母(Fritilla riapallidiflora Schvek)根系分泌物成分中的1,3,5-三烯丙基-1,3,5-三嗪-2,4,6(1H,3H,5H)三酮、酚酸和二者的混合液对伊贝母幼苗的影响。结果表明,伊贝母根系分泌物成分对伊贝母幼苗体内的保护酶SOD起到抑制作用,但对POD、CAT的活性既有抑制作用亦有促进作用。对幼苗体内MDA及叶绿素含量有促进作用。     

Effects of exogenous cyanide on root physiology and metabolism of peach seedlings北大核心CSCD

【Objective】Peach (Prunus persica) is an economically important fruit crop worldwide. With the increasing demand and the reduced cultivated land acreage of peach, replant problem (also known as replant disease) has become increasingly prominent, and has been causing severe economic losses. Autotoxicity is a special kind of allelopathy, and is considered to be a major factor resulting in the prevalence of peach replant problem. Cyanide (CN-) is a major autotoxin that causes peach replant problem, but the information on physiological and metabolic responses of peach plants under CN- treatment is quite limited. Thus, the specific responsive mechanisms of peach plants to CN- are worthy of in-depth exploration. The study aimed to investigate the effects of CN- treatment on the morphological, physiological, and metabolic parameters in roots of peach seedlings, so as to provide new insights into the response mechanisms of peach plants to CN- treatment. 【Methods】The natural root environment of dead and living trees was investigated in the peach orchard of Huazhong Agricultural University. The effects of exogenous CN- treatment on root growth and seed germination were assessed on peach germinatedseeds (treated with 0, 0.25, 0.5, and 1.0 mmol•L-1 CN-) and lettuce seeds (treated with 0 and 0.5 mmol•L-1 CN- ). The peach root tips treated with 0 and 0.5 mmol • L-1 CN- were subjected to anatomical assessments using paraffin sectioning and staining (including transverse and longitudinal sections). The contents of H2O2 and MDA, as well as the activities of CAT, POD, and SOD from 0 and 0.5 mmol•L-1 CNstressed peach roots were detected. The expression levels of CAT, POD, and SOD-encoding genes were tested using qRT-PCR. To further understand the CN- -induced metabolic changes, peach roots treated with 0 and 0.5 mmol • L-1 CN- for 5 d were subjected to gas chromatography-mass spectrometry (GCMS) analysis. 【Results】The CN- was mainly distributed in 0-40 cm soil layer, and the content was significantly higher in the soil with dead trees than with living trees. The CN- content in soil was predominantly detected adjacent to peach roots, and gradually decreased with the distance from peach roots. The CN- contents showed an upward trend year by year in the bulk soils with the dead and living trees, where the dead trees contained more CN- than the living trees. The CN- contents varied in different size of peach roots, the fine roots (Φ < 5 mm) contained more CN- than the middle size (5 mm ≤ Φ ≤ 10 mm) and the large size roots (Φ > 10 mm). We evaluated the effect of different CN- concentrations (0, 0.25, 0.5, and 1.0 mmol•L-1) on the growth performance of peach germinated-seeds. The result showed that 0.25 mmol • L-1 CN- treatment boosted root growth, while 0.5 and 1.0 mmol • L-1 inhibited root growth with decreased root length and lateral root numbers. The allelopathy sensitivity index indicated that the effects of CN- treatment on peach growth in a concentration-dependent manner, showing low concentration promoted growth but high concentration inhibited it. Additionally, with 0.5 mmol•L-1 CNtreatment, the transverse and longitudinal sections of the root tip showed a severely wrinkled root epidermis, ruptured root cortex cells, and larger intercellular spaces. 0.5 mmol•L-1 CN- treatment also significantly inhibited lettuce seed germination and biomass. The contents of H2O2 and MDA in peach roots significantly increased, and the activities of SOD, POD, and CAT, as well as their respective encoding genes expression, significantly increased with 0.5 mmol•L-1 CN- treatment. The GC-MS analysis showed that 0.5 mmol • L-1CN- treatment dramatically increased contents of numerous amino acids, including proline, glycine, serine, asparagine, alanine, glutamate, GABA etc. Moreover, CN- treatment significantly affected carbohydrate levels in peach roots. 【Conclusion】The CN- contents were associated with the distribution and size of plant roots, and the decomposition of plant residuals. Exogenous CNsupply markedly retarded peach root growth. CN- feeding also gave rise to oxidative stress, reflecting by the increased ROS and MDA levels, and antioxidant enzyme activities. CN- supplementation also induced metabolic reprogramming, displaying a disorder of amino acid and carbohydrates metabolism. © 2022, Office of Journal of the Fruit Science. All right reserved.     

凹土对辣椒自毒作用修复的生理生化机制研究

采用盆栽试验,在土壤中添加邻苯二甲酸二丁酯(DBP)模拟自毒物质,以凹土为修复剂,通过测定辣椒的生长指标和生理生化指标,研究凹土对DBP的修复效果。结果表明:DBP对辣椒生长和生理代谢有显著自毒作用,添加适量凹土能够修复DBP对辣椒造成的自毒作用;当凹土添加量为20 g/kg时,凹土对DBP的修复效果最好,表现为辣椒根系的丙二醛(MDA)含量最低,过氧化物酶(POD)活性和过氧化氢酶(CAT)活性最强,根系的总吸收面积、活跃吸收面积和比表面最大,根系活力最强,根系呼吸速率最大,叶绿素含量最高,植株生长和干物质积累最多;当添加量为80 g/kg时,膜脂过氧化加剧,根系吸收能力下降,植株生长和干物质积累减少,凹土对DBP的修复作用消减或消失;凹土添加量应控制在20~40 g/kg。     

异龄苜蓿土壤浸提液对3种植物种子萌发的影响

采用自甘肃庆阳和定西地区不同年龄紫花苜蓿(Medicago sativa L.)土壤制备浸提液,应用纸上发芽法检测其对苜蓿、萝卜(Raphanus sativus L.)和小麦(Triticum aestivum L.)种子萌发的影响.结果表明:不同生长年龄苜蓿土壤浸提液对苜蓿种子萌发以及胚根和胚芽的抑制程度为年>3年>9年,在庆阳龄苜蓿土壤浸提液(00 g干土/L)中苜蓿发芽率下降18%,其胚芽和胚根显著受抑(P<0.0),比对照分别降低69%和80%.在平均降水391mm的定西,4年以下苜蓿土壤无明显自毒性;苜蓿秋季翻耕休闲有利于3个供试种的萌发及胚根和胚芽的生长,有效解除了年龄以上苜蓿土壤的自毒效应,苜蓿-小麦轮作系统中,苜蓿后茬小麦建植不受苜蓿毒性的影响.     

化感植物根际生物学特性研究现状与展望

植物的根际是一个复杂的微生态系统,植物的根必须与入侵的邻近植物根及大量以有机物质为营养的细菌、真菌、土存害虫相互竞争空间、水分、矿质营养等。在土壤中,根与根际生物体的相互作用相当复杂且受到许多土壤因素的影响,地下根际生物体以根分泌物为媒介相互作用的机制比发生在地表的生物体的相互作用复杂的多。越来越多的试验表明,根分泌物在根与根、根与根际微生物间起着重要作用,并以其为媒介在植物与环境的相互作用中起着传递信息的作用。本文在简要综述前人研究的基础上,深入探讨了化感植物根际生物学问题及攻克途径,以期为深入研究植物化感作用提供依据。     

当归自毒作用和其对不同作物的化感效应

为探讨当归(Angelica sinensis) 连作障碍产生的原因和建立合理的轮作制度,在室内采用离体生测方法,研究当归水浸提物对当归、油菜(Brassica campestris)、小麦(Triticum aestivum)和蚕豆(Vicia faba)的化感效应。结果表明:当归具有较强的自毒作用,且自毒作用随浓度增加而增加;当归水浸液浓度为0.0125, 0.0250, 0.0500和0.1000 g·mL^-1时,当归发芽率分别为36.25%,5.83%,0.83%和0%。当归水浸提物对3种植物种子萌发均表现为化感抑制作用,并且化感抑制作用随浓度增加而增加,种子萌发次序是油菜>小麦>蚕豆。在同一浓度处理下,对小麦和油菜胚根的化感抑制作用大于胚芽,而对蚕豆胚根的化感抑制作用小于胚芽。油菜和小麦的萌发率和萌发指数大于蚕豆。当归水浸提物对去胚乳小麦幼芽、幼根的平均抑制率分别为5.63%和18.01%;当归对黑暗条件下培养的油菜幼芽、幼根的抑制率分别为16.25%和50.36%,表明当归化感物质对植物非光合作用的抑制作用强于光合作用。因此,当归的自毒作用是造成连作障碍的原因之一;当归对蚕豆的化感作用小于油菜和小麦,蚕豆可以用于当归轮作体系,缓解因自毒作用而引起的连作障碍。     

苜蓿的自毒性研究进展

介绍了苜蓿自毒性的产生机制和作用模式,分析了影响自毒性的各种因素,提出了相应的避免或降低自毒性的措施,并对苜蓿自毒性及相关的他感作用将来的研究进行了展望。     

紫花苜蓿品种间自毒性物质含量差异研究

利用生物测定和高效液相色谱方法研究紫花苜蓿（Medicago sativa L.）自毒性现象,并评价不同品种苜蓿自毒性差异。结果显示,苜蓿叶浸提物抑制受体苜蓿vector的胚根生长,对照与所有处理的差异均达到极显著水平（P<0.01）。50个苜蓿品种按自毒性强度可分为3大类9个小组,自毒性最弱的组只有一个品种,为Key;最强的组有GS20001X、超级阿波罗、射手、NS00-32、牧野、WL232HQ共5个;其余品种分布在上述两组之间。在苜蓿叶浸提物中检测到香豆素、邻香豆酸、间香豆酸和对香豆酸4种目标酚类物质。     

茄子秸秆水提物自毒作用初探

试验研究茄子秸秆水提物自毒作用结果表明,茄子干秸秆水提物原液浓度为0 .0 15 g/ mL时明显抑制茄时明显抑制茄子胚根的生长,低浓度提取物原液对胚芽生长有一定促进作用,当其浓度增至0 .0 75g/ mL时明显抑制茄时茄子胚芽生长也受抑,表明茄子秸秆水提物对茄子生长有较强的自毒作用;水提物中醇溶性组分对茄子胚根、胚芽生长的影响与水提物原液表现一致,且对水培茄子幼苗生长有较强抑制作用,表明醇溶性组分中含有大量自毒物质。茄子幼苗根系活力随水提物中醇溶性组分浓度的增加而降低,植株对NO-3 、PO3 -4、K 、Mg2 和Ca2 等离子的吸收受阻,因而抑制离子的吸收是水提物中自毒物质发挥作用的重要因素之一。