Water stress, photosynthesis and early growth patterns of cuttings of three Populus clones

Photosynthetic attributes, leaf area and early root growth patterns were studied in three Populus clones to identify traits associated with superior growth potential on sites where water could be a limiting factor. It was found that early root growth and superior leaf area production were more closely related to growth potential than were photosynthetic capacity or carboxylation efficiency. A hybrid clone of Populus nigra var. charkowiensis (syn. P. nigra var. plantierensis) x P. nigra cv. 'Incrassata' (NE308) had more leaf area production and greater root system development in both wet and dry soil than did a P. trichocarpa clone (T6) and a P. balsamifera clone (B3). Despite greater above- and below-ground productivity, plants of clone NE308 had significantly lower photosynthetic capacity and carboxylation efficiency and a slightly higher CO(2) compensation point than plants of clones T6 and B3. Rapid early leaf and root growth appear to be key attributes associated with productivity in these clones regardless of soil water availability.     

Insect-resistant mechanism of transgenic triploid of Chinese white poplar

The activities of antidotal enzymes and digestive enzymes of Clostera anachoreta (Fabricius) instar larvae, feeding on leaves of three kinds of insect-resistant clones of transgenic triploid of Chinese white poplar, after 4, 12, 24, 48, 72 and 96 h, were investigated. The results showed that, feeding on clone 7, the activity of esterase, carboxylesterase, and mixed-function oxidases in the midgut of the larvae was very much decreased. Feeding on clone 10, those results were less than those of clone 7 and there were few changes on the larvae, which fed on clone 26. The changes of the amylase in the midgut of larvae were the same as those described above. However, the activities of glutathione S-transferase and proteinase were complex, increased markedly after 24 h feeding on clone 7, and then declined rapidly. The same changes were taking place on the larvae feeding on clone 10. There were many slight changes in glutathione S-transferase of the larvae, feeding on clone 26; no changes occurred in the proteinases of the midgut. Thus, the antidotal enzymes and digestive enzymes in the midgut of the larvae were inhibited. This may be the main mechanism of the transgenic triploid of Chinese white poplar. __________ Translated from Journal of Agricultural University of Hebei, 2005, 28(5) [译自: 河北农业大学学报, 2005, 28(5)]     

不同杨树无性系光合作用与其抗旱能力的初步研究

不同杨树无性系光合作用与其抗旱能力的初步研究刘建伟，刘雅荣，王世绩（中国林业科学研究院林业研究所北京１０００９１）关键词杨树无性系，光合作用，水势补偿点，水分胁迫，抗旱在水分逆境的研究中，净光合速率的降低已成为显著的特征，针叶、阔叶树的种间变化曾有许...     

Prevention of 4-nitroquinoline 1-oxide-induced rat tongue carcinogenesis by garlic.

The present study was undertaken to examine the inhibitory effect of garlic (Allium sativum) on 4-nitroquinoline 1-oxide (4NQO)-induced tongue carcinogenesis in male rats, both in the initiation and post-initiation phases. Lipid peroxidation, reduced glutathione (GSH), glutathione peroxidase (GPx), and glutathione S-transferase (GST) were used to monitor the chemopreventive potential of garlic. Biochemical estimations were carried out on tumour and normal tongue tissues. Diminished lipid peroxidation in the tumour tissue was accompanied by a significant increase in the levels of GSH, GPx and GST. Administration of garlic (250 mg/kg, p.o., three times a week) effectively suppressed 4NQO-induced tongue carcinogenesis as revealed by the absence of carcinomas in the initiation phase and their reduced incidence in the post-initiation phase. The results of the present study suggest that garlic may exert its chemopreventive effects by modulating lipid peroxidation and enhancing the levels of GSH, GPx and GST.     

7个接骨木无性系苗木对盐胁迫的生理响应与评价

【目的】为揭示接骨木无性系在盐害胁迫下的生长生理指标的响应,确定接骨木对盐渍环境的适应能力及耐盐性,为盐碱地造林提供优良无性系。【方法】以接骨木属3个种的7个无性系为试验材料,采用盆栽试验的方法,利用不同浓度的NaCl溶液进行胁迫处理,比较不同处理下各无性系的生长、生理等指标的变化,结合主成分分析对不同无性系进行综合评价。【结果】受NaCl胁迫的影响,7个接骨木无性系的苗高、地径和生长量增量生长指标均表现出下降的趋势,其中,无性系XY-2的生长指标受NaCl胁迫影响最小,较对照T0,其苗高降幅14.9%,表现出较强的耐盐性;各无性系根冠比和细胞膜透性指标出现升高趋势,无性系JY-1和XY-3的根冠比增幅最大,较对照T0,增幅分别为84.0%和88.2%。无性系PT-3和XY-1的细胞膜透性增幅最小;7个接骨木无性系的叶绿素含量不断下降,较对照T0,无性系XY-3的叶绿素含量最大,下降幅度为44.3%,且呈显著性差异水平;7个接骨木无性系的超氧化物歧化酶(SOD)活性均不同程度地出现先上升后下降的趋势,无性系PT-3的SOD值最大;渗透调节物可溶性糖含量和脯氨酸含量均随NaCl胁迫浓度增加而增加,可溶性糖含量增幅最大的无性系为XY-3和XY-1,较对照T0,增幅分别为2.13倍和1.79倍。在溶液盐分浓度6‰胁迫下,7个接骨木无性系中脯氨酸含量最大的无性系是XY-1。【结论】综合评价得出接骨木无性系耐盐程度由强到弱依次为XY-2、XY-3、XY-1、JY-1、PT-1、PT-3、PT-2。其中,无性系XY-2、XY-3具有较强耐盐性,可作为耐盐接骨木无性系材料进行下一步研究。     

低磷胁迫下不同杉木家系根系H^+流动态变化

通过分析不同杉木家系在不同供磷处理下根系H^+流变化规律,探讨根系H^+流与杉木适应低磷胁迫调控的关系,为揭示磷高效利用杉木适应低磷胁迫的内在机制提供科学依据。以前期筛选出的不同磷利用效率杉木家系M28与M32为研究对象,通过设计3个供磷处理[正常供磷(H-P),31 mg·L^-1;中度缺磷(L-P),16 mg·L^-1;重度缺磷(N-P),0 mg·L^-1]和3个时间处理梯度(3、8、15 d)室内水培试验,并利用非损伤微测技术(NMT)分别测定两个家系在不同供磷处理和不同时间处理梯度下完整根系及不同部位的H^+动态变化规律。结果表明:不同杉木家系完整根系H^+全程表现为内流,但二者H^+流变化存在显著差异,M28完整根系H^+吸收表现为8 d>15 d>3 d,M32在不同时间处理下H^+的变化无显著差异(P>0.05)。结合根系不同部位H^+流向分析可得,M28与M32仅在L-P和N-P处理3 d时表现出少量H^+外排现象,其中M28对外界磷环境的感应比M32更为敏感,在L-P处理下就发生H^+外排现象,M32在N-P处理才发现H^+外排。随着时间推移,在处理8、15 d后,两个杉木家系均未观测到H^+的外排,可见低磷胁迫下根系H^+外排是一种应激反应。不同杉木家系根系H^+流在低磷环境下表现出不同的适应性变化,其中M28根系的H^+流对外界磷环境的改变更为敏感。     

Rapid evolution of Ophraella communa cold tolerance in new low-temperature environments

Low winter temperatures severely stress newly arriving insect species. Adaptive evolutionary changes in cold tolerance can facilitate their establishment in new environments. Ambrosia artemisiifolia, a noxious invasive plant, occurs throughout China. Ophraella communa, a biological control agent of A. artemisiifolia, mainly occurs in southern China. However, in 2012, it established populations in Beijing (39.98°N, 115.97°E) following introduction from Laibin (23.62°N, 109.37°E), implying cold adaptation. The mechanisms underlying its rapid evolution of cold tolerance remain unknown. We investigated the levels of cryoprotectants and energy reserves in adult O. communa from two latitudes. In high-latitude insects, we found high trehalose, proline, glycerol, total sugar, and lipid levels; five potential genes (Tret1a, Tret1b, Tret1-2, P5CS, and GST), responsible for regulating cold tolerance and involved in trehalose transport, proline biosynthesis, and glutathione S-transferase activation, were highly expressed. These hybridisation changes could facilitate cold temperature adaptation. We demonstrate the genetic basis underlying rapid adaptation of cold tolerance in O. communa, explaining its extension to higher latitudes. Thus, specialist herbivores can follow host plants by adapting to new temperature environments via rapid genetic evolution.

     

Novel Prunus rootstock somaclonal variants with divergent ability to tolerate waterlogging

Plants require access to free water for nutrient uptake, but excess water surrounding the roots can be injurious or even lethal because it blocks the transfer of free oxygen between the soil and the atmosphere. Genetic improvement efforts in this study were focused on the increased tolerance in roots to waterlogging. Among a pool of clones generated in vitro from leaf explants of rootstock Mr.S.2/5 of Prunus cerasifera L., the S.4 clone was flood tolerant whereas the S.1 clone was sensitive. The S.4 clone formed adventitious roots on exposure to flooding. Moreover, the chlorophyll content and mitochondrial activity in the leaf and root, soluble sugar content, alcohol dehydrogenase activity and ethylene content were different between the clones. The sorbitol transporter gene (SOT1) was up-regulated during hypoxia, the alcohol dehydrogenase genes (ADH1 and ADH3) were up-regulated in the leaves and down-regulated in the roots of the S.4 clone during hypoxia, and the 1-aminocyclopropane-1-oxidase gene (ACO1) was up-regulated in the leaves and roots of the S.4 clone during hypoxia and down-regulated in the wild-type roots. In addition, in the S.4 root, hypoxia induced significant down-regulation of a glycosyltransferase-like gene (GTL), which has a yet-undefined role. Although the relevant variation in the S.4 genome has yet to be determined, genetic alteration clearly conferred a flooding-tolerant phenotype. The isolation of novel somaclonals with the same genomic background but with divergent tolerance to flooding may offer new insights in the elucidation of the genetic machinery of resistance to flooding and aid in the selection of new Prunus rootstocks to be used in various adverse environments.     

Alteration of glutathione S-transferase properties during the development of <Emphasis Type="Italic">Micromelalopha troglodyta</Emphasis> larvae (Lepidoptera: Notodontidae)

Micromelalopha troglodyta (Graeser) is an important pest of poplar in China. Glutathione S-transferases (GSTs) are known to be responsible for adaptation mechanisms of M. troglodyta. The activities and kinetic constants of glutathione S-transferases in M. troglodyta were studied. Significant differences in glutathione S-transferase activity and kinetic characteristics were observed among five instars of M. troglodyta larvae. Furthermore, the inhibition of glutathione S-transferase activity in five instars by 24 inhibitors was conducted. The results show the inhibition of GST activity of different instars by 24 inhibitors was different. For GST activity in the 1st instar, chlorpyrifos, lambda-cyhalothrin, endosulfan, abamectin, fipronil and pyridaben were the best inhibitors tested, and for GST activity in the 2nd instar, tannic acid and quercetin were the most potent inhibitors tested, and for GST activity in the 3rd instar, the inhibitory effects of quercetin, chlorpyrifos and lambda-cyhalothrin were the highest, and for GST activity in the 4th instar, quercetin and lambda-cyhalothrin were the best inhibitors, and the inhibitory effect of phoxim was the highest for GST activity in the 5th instar. Our results show that glutathione S-transferases in different instars are qualitatively different in isozyme composition and thus different in sensitivity to inhibitors.     

Shoot culture dynamics of six Populus clones

Shoot tips of five genotypically diverse Populus clones, P. alba x P. grandidentata 'Crandon,' P. nigra 'Betulifolia' x P. trichocarpa, P. nigra x P. laurifolia 'Strathglass,' P. maximowiczii x P. trichocarpa 'Androscoggin' and P. deltoides x P. nigra 'Eugenei,' were collected from hardwood cuttings, sterilized,and established in vitro. Stable shoot cultures were obtained from all clones except P. deltoides x P. nigra 'Eugenei'. The four poplar clones that formed stable shoot cultures together with a previously established P. tremula 'Erecta' clone were placed as two-node explants on either Murashige and Skoog medium or Woody Plant Medium containing benzyladenine to determine the rate of shoot multiplication, shoot growth and other responses of the clones. All five poplar clones showed rapid shoot multiplication when cultured in the presence of 0.4-1.0 microM benzyladenine on Murashige and Skoog medium, although P. tremula 'Erecta' produced a greater number of healthy shoots when grown on Woody Plant Medium. Individual shoot growth of all clones was more vigorous when the medium contained 0-0.1 microM benzyladenine, and 100% of such shoots rooted ex vitro.     

杨树无性系根系吸收H2PO4-动力学特征与磷营养效率

在温室条件下,应用整株植物长期吸收的营养液培养方法研究杨树无性系根系吸收H2PO4-动力学特性及其与磷营养效率的关系,以揭示杨树不同无性系间磷营养效率差异的机理.结果表明,高效型无性系S17、S19和105根系对H2PO4-离子的吸收能力明显强于低效型无性系106、797、Ⅰ-69、1388和3244.与低效型无性系相比,S17、S19和105具有较小的米氏常数Km和吸收临界浓度Cmin,说明它们的根系对H2PO4-的亲合力、对低磷浓度的耐受能力较强.在缺磷胁迫条件下,S17、S19和105根系系统对H2PO4-的亲合能力可增加20%以上,其Km值分别从13.8、13.4和14.0 μmol·L-1下降到10.1、10.7和11.2 μmol·L-1,而低效型无性系的亲合力则变化很小,增加不足5%.同样,高效型无性系对低磷的耐受能力可增加85%以上,其Cmin分别从2.55、2.94和2.68 μmol·L-1下降到0.30、0.35和0.40 μmol·L-1,但低效型无性系的增加均不足15%.杨树无性系在根系吸收H2PO4-动力学特性方面的不同是其磷营养效率差异的重要原因之一.最大吸收速率Vmax,作为根系吸收动力学参数之一,对阐明杨树无性系磷营养效率的作用尚不够确定.     

湘林黑杨新无性系不同部位水培生根性状研究

对湘林-90等6个杨树新无性系及中汉-17、I-69杨1年生苗,自下而上按4部位分别裁截插穗,进行水培生根试验,探索杨树水培后皮层凸起、先期不定根数量、凸起成根率及根长在无性系、区分段间的分布规律及相关性。     

Organic solute accumulation and dehydration tolerance in three water-stressed Populus deltoides clones

The relationship between osmotic potential, water-soluble organic solutes and electrolyte leakage was investigated in three greenhouse-grown eastern cottonwood (Populus deltoides Bartr.) clones. The Ohio Red (from southern Ohio) and Platte (from eastern Nebraska) clones were selected because they differ in dehydration tolerance, gas exchange and osmotic potential. A third clone, Wildcat (from western Nebraska) was included because of its origin in a very dry area. Plants were either watered daily (control) or watered every 4-6 days (preconditioned). A third group of plants was watered daily until it was water-stressed at the end of the experiment (nonconditioned). Leaves for osmotic potential and water-soluble solute determinations were sampled at predawn after plants were rewatered. All clones showed osmotic adjustment ranging from 0.23 to 0.48 MPa. Organic solutes contributed up to 48% of the total osmotic adjustment. The solutes that contributed at least -0.05 MPa each to leaf osmotic potential in any clone were sucrose, malic acid, glucose, fructose, myoinositol and salicin. Fructose and glucose concentrations were unchanged or declined in preconditioned Ohio Red and Platte but increased in Wildcat. The Ohio Red clone had the highest sucrose concentration in both well-watered and preconditioned plants, and a lower injury index (more membrane stability) than Wildcat in the preconditioned plants, whereas nonconditioned Platte displayed the greatest electrolyte leakage of all clones and treatments. Cell membrane stability was correlated to osmotic potential and sucrose concentration only in Ohio Red.     

星天牛转录组及三大解毒酶家族相关基因系统发育分析

【目的】研究星天牛转录组信息及体内细胞色素P450单加氧酶(cytochrome P450 monooxygenase,CYP)、羧酸酯酶(carboxylesterase,CarE)和谷胱甘肽S-转移酶(glutathione S-transferase,GST)三大解毒酶系的表达谱情况,通过构建系统进化树,探析其这3种酶系基因家族的类别及其系统演化关系,为星天牛对多寄主种类的适应性与杀虫剂的抗药性机制研究提供依据。【方法】采用新一代高通量测序技术Illumina HiSeq TM 2500 对星天牛进行转录组测序与数据分析,通过数据筛选并进一步与鞘翅目近缘物种的解毒酶同源蛋白进行系统发育分析。【结果】经测序、序列拼接得到55 260条unigenes,将其与公共数据库进行同源比对,注释了32 247条unigenes,在Swiss-Prot数据库注释的unigenes的数量最多(99.11%);注释到Nr数据库时与赤拟谷盗的unigenes同源性最高(60.25%);在GO数据库中,共有8 083个unigenes被成功注释,根据其功能大致可分为3 类47 亚类;在KEGG数据库中,4 600 条unigenes与162个预测路径可以匹配。通过基因注释发现248条解毒酶系基因在星天牛体内表达,包括139条CYP基因、72条CarE基因、37条GST基因。系统发育分析发现,星天牛的大部分CYP基因都至少与一种鞘翅目近缘物种的CYP基因聚类在一起,P450基因中的CYP6家族数量与其他近缘物种(鞘翅目)类似,包含的基因数量最多;CarE解毒酶蛋白基因主要为β-酯酶、神经趋化蛋白、外源性代谢酶、未知等4种类型,分别可能参与星天牛的一些激素以及信息素的加工、神经和发育过程、消化与解毒等生理过程;星天牛的GST基因聚类主要包含Microsomal GST、Sigma GST、Omega GST、Delta GST、Theta GST等亚家族,具有保护生物大分子免受氧化损伤、催化活力等功能。【结论】本研究获得星天牛的转录组信息,初步探明星天牛体内三大解毒酶系的表达谱及分化情况,可为星天牛对多寄主种类的适应性与杀虫剂抗药性的产生及遗传机制研究提供基础数据和参考。     

Drought stress tolerance analysis of Populus ussuriensis clones with different ploidies

The selection of drought-tolerant plants is an important aspect of plant breeding.We studied physiological and biochemical mechanisms of different ploidies of Populus ussuriensis Kom.that relate to drought stress tolerance.We used a 5%(v/v)polyethylene glycol(PEG-6000)solution to simulate drought stress.We recorded leaf phenotypes including color,dry area and curl degree.We evaluated sequential variations in some drought stress tolerance-related physiological and biochemical indices and compared these among diploid clones(CK),triploid clones(T12)and tetraploid clones(F20).T12 leaves exhibited slightly more drought stress damage than CK and F20 leaves.CK leaves suffered the most severe drought stress damage.The physiological and biochemical indices of the different ploidies differed significantly 12 days after drought stress treatment.The activities of superoxide dismutase,peroxidase,catalase and proline in the triploid(T12)leaves were the highest.The relative electric conductivity and malondialdehyde content of T12 leaves were the lowest.The index values of F20 were between those ofthe diploid and triploid.In consideration of these results,the drought resistance of the three different ploidies of P.ussuriensis can be ranked as T12>F20>CK.We speculate that the gene expression patterns of polyploid clones of poplar will change after genome doubling and that some of the drought stress tolerance-related physiological and biochemical indices will be improved,resulting in greater drought tolerance of polyploid clones.     

Resistance of new Belgian poplar clones to British isolates of the bacterial canker pathogen,Xanthomonas populi

Forty-nine new poplar clones, bred in Belgium and screened there for resistance to bacterial canker caused by Xanthomonas populi, were additionally screened in southern England, using British isolates of the bacterium. Thirty-five of the test clones ranked better than the clone ‘Boelare’, which is already registered in the UK as an approved clone, and is regarded as having acceptable resistance. The registered clone ‘Ghoy’ was more susceptible, and outranked only four test clones. Preliminary measurements of canker length and stem girdling index showed differences between five bacterial isolates.