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131.
为了建立有效的丽格海棠组培苗离体生根系统,降低培育丽格海棠组培苗离体生根的成本,对基本培养基的不同离子强度、白糖浓度以及培育琼脂浓度对丽格海棠的组培苗离体生根进行了研究。研究发现,培养基的基本离子强度和白糖浓度对丽格海棠组培苗的离体生根有一定的影响,从降低成本的角度考虑,1/4MS培养基为最佳的培养基,15 g·L-1的白糖为最佳的白糖浓度。所采用的琼脂浓度对丽格海棠组培苗的离体生根没产生明显的影响,从降低成本的角度选择3 g·L-1的琼脂为最佳的琼脂浓度。 相似文献
132.
Martinez-Wittinghan FJ Srinivas M Sellitto C White TW Mathias RT 《The Journal of membrane biology》2006,211(3):163-171
Mefloquine (MFQ) selectively blocks exogenously expressed gap junction channels composed of C×50 but not C×46. The purpose
of the current study was to evaluate MFQ effects on wild-type (WT) mouse lenses that express both C×50 and C×46 in their outer
shell of differentiating fibers (DFs). Lenses in which C×46 was knocked into both C×50 alleles (KI) were used as controls;
MFQ had no effect on coupling in these lenses. When WT lenses were exposed to MFQ, the DF coupling conductance decreased significantly,
suggesting that C×50 contributes about 57% of the coupling conductance in DF and C×46 contributes 43%. Remarkably, in the
presence of MFQ, the 43% of the channels that remained open did not gate closed in response to a reduction in pH, whereas
in the absence of MFQ, the same pH change caused all the DF channels to gate closed. Since MFQ is a selective blocker of C×50
channels, it appears that C×46 channels lack pH-mediated gating in the absence of functional C×50 channels but are pH-sensitive
in the presence of C×50 channels. These results suggest the two types of channels interact and gate cooperatively. 相似文献
133.
Unusual Fine Root Distributions of Two Deciduous Tree Species in Southern France: What Consequences for Modelling of Tree Root Dynamics? 总被引:3,自引:0,他引:3
The spatial distribution of fine roots of two deciduous tree species was investigated in contrasting growing conditions in
southern France. Hybrid walnut trees (Juglans regia×nigra cv. NG23) and hybrid poplars (Populus euramericana cv. I214) were both cultivated with or without annual winter intercrops for 10 years on deep alluvial soils. Soil samples
for measuring the fine root distribution of both trees and crops were obtained by soil coring down to 3-m depth at several
distances and orientations from the tree trunk. The distribution of live fine roots from walnut and poplar trees was patchy
and sometimes unexpected. In the tree-only stands, fine root profiles followed the expected pattern, as fine root density
decreased with increasing depth and distance from the tree trunk. However, many fine root profiles under intercropped trees
were uniform with depth, and some inverse profiles were observed. These distributions may result from a high degree of plasticity
of tree root systems to sense and adapt to fluctuating and heterogeneous soil conditions. The distortion of the tree root
system was more pronounced for the walnut trees that only partially explored the soil volume: in the tree-only stand, the
walnut rooting pattern was very superficial, but in the intercropped stand walnut trees developed a deep and dense fine root
network below the crop rooting zone. The larger poplars explored the whole available soil volume, but the intercrop significantly
displaced the root density from the topsoil to layers below 1 m depth. Most tree root growth models assume a decreasing fine
root density with depth and distance from the tree stem. These models would not predict correctly tree–tree and tree–understorey
competition for water and nutrients in 3D heterogeneous soil conditions that prevail under low-density tree stands. To account
for the integrated response of tree root systems to such transient gradients in soils, we need a dynamic model that would
allow for both genotypic plasticity and transient environmental local soil conditions. 相似文献
134.
Carbon isotopic composition of soils subjected to C3–C4 vegetation change can be used to estimate C turnover in bulk soil and in soil organic matter (SOM) pools with fast and intermediate
turnover rates. We hypothesized that the biological availability of SOM pools is inversely proportional to their thermal stability,
so that thermogravimetry can be used to separate SOM pools with contrasting turnover rates. Soil samples from a field plot
cultivated for 10.5 years with the perennial C4 plant Miscanthus×gigantheus were analyzed by thermogravimetry coupled with differential scanning calorimetry (DSC). Three SOM fractions were distinguished
according to the differential weight losses and exothermic or endothermic reactions measured by DSC. The δ13C and δ15N values of these three fractions obtained by gradual soil heating were measured by IRMS. The weight losses up to 190 °C mainly
reflected water evaporation because no significant C and N losses were detected and δ13C and δ15N values of the residual SOM remained unchanged. The δ13C values (−16.4‰) of SOM fraction decomposed between 190 and 390 °C (containing 79% of total soil C) were slightly closer
to that of the Miscanthus plant tissues (δ13C = −11.8‰) compared to the δ13C values (−16.8‰) of SOM fraction decomposed above 390 °C containing the residual 21% of SOM. Thus, the C turnover in the
thermally labile fraction was faster than that in thermally stable fractions, but the differences were not very strong. Therefore,
in this first study combining TG-DSC with isotopic analysis, we conclude that the thermal stability of SOM was not very strongly
related to biological availability of SOM fractions. In contrast to δ13C, the δ15N values strongly differed between SOM fractions, suggesting that N turnover in the soil was different from C turnover. More
detailed fractionation of SOM by thermal analysis with subsequent isotopic analysis may improve the resolution for δ13C. 相似文献
135.
干旱胁迫对新西伯利亚银白杨抗氧化系统和幼苗生长的影响 总被引:3,自引:1,他引:2
以1年生新西伯利亚银白杨幼苗为试验材料,研究了不同干旱胁迫强度下新西伯利亚银白杨抗氧化系统的生理响应和幼苗生长状况。结果表明,在20%~95%土壤含水量范围内,随着干旱胁迫强度的增加,幼苗质膜透性升高,保护酶活性呈规律性变化;同时,幼苗生长受到的抑制作用加剧;恢复供水后,幼苗质膜透性和各保护酶活性均恢复到接近对照水平。因此认为,在土壤含水量在田间持水量的20%~95%,即绝对容积含水率11.5%~43.7%之间新西伯利亚银白杨具备良好的适应调节能力,其最适土壤容积含水率为27.6%~29.9%。 相似文献
136.
137.
Sanjaya Gyawali Reda Amezrou Ramesh Pal Singh Verma Robert Brueggeman Sajid Rehman Loubna Belqadi Mustapha Arbaoui Prabin Tamang Murari Singh 《Journal of Phytopathology》2020,168(5):254-266
This study was conducted to identify stable resistance to net form of net blotch (NFNB) in spring barley in Moroccan environments. Seedling resistance to NFNB was evaluated by inoculating 336 barley genotypes with two NFNB isolates LDNH04Ptt-19 and TD-10 in the greenhouse. These genotypes were evaluated for adult plant resistance to NFNB under seven environments in Morocco in 2015 and 2016. The disease severity was estimated at GS 77–87 on barley leaves using a double-digit scale. To investigate stability of resistance, 149 barley genotypes were subjected to AMMI analysis. At the seedling stage, differential responses of barley genotypes to different NFNB isolates were identified, whereas genotypes had variable stability to NFNB resistance at the adult stages. Five genotypes, AM-68, AM-95, AM-250, AM-267 and AM-322, were resistant to both NFNB isolates at the seedling stage. There were significant (p < .001) effects of genotype (G) and G × E interaction on NFNB severity for barley genotypes at the adult stage. The principal components, IPCA1 and IPCA2, accounted for 48.4% and 18.7% variation for NFNB severity, respectively. The AMMI stability values (ASVs) ranged from 0.01 to 15.5, and fifty-nine barley genotypes had stable responses (ASV ≤ 0.05) across all seven environments. Specifically, two stable genotypes, AM-187 and AM-244, had lower mean NFNB severities across all environments, suggesting a quantitative resistance in these genotypes. Divergent environmental responses of NFNB severity were measured in Sidi El Ayedi 2015 and Sidi Allal Tazi 2016, suggesting that these environments may be suitable to capture resistance to diverse pathotypes. These stable genotypes are valuable resources for introgression of both qualitative resistance and quantitative resistance to NFNB in future. 相似文献
138.
Nafiseh Geshnizjani Basten L. Snoek Leo A. J. Willems Juriaan A. Rienstra Harm Nijveen Henk W. M. Hilhorst Wilco Ligterink 《Plant, cell & environment》2020,43(8):1973-1988
Seed quality and seedling establishment are the most important factors affecting successful crop development. They depend on the genetic background and are acquired during seed maturation and therefor, affected by the maternal environment under which the seeds develop. There is little knowledge about the genetic and environmental factors that affect seed quality and seedling establishment. The aim of this study is to identify the loci and possible molecular mechanisms involved in acquisition of seed quality and how these are controlled by adverse maternal conditions. For this, we used a tomato recombinant inbred line (RIL) population consisting of 100 lines which were grown under two different nutritional environmental conditions, high phosphate and low nitrate. Most of the seed germination traits such as maximum germination percentage (Gmax), germination rate (t50) and uniformity (U8416) showed ample variation between genotypes and under different germination conditions. This phenotypic variation leads to identification of quantitative trait loci (QTLs) which were dependent on genetic factors, but also on the interaction with the maternal environment (QTL × E). Further studies of these QTLs may ultimately help to predict the effect of different maternal environmental conditions on seed quality and seedling establishment which will be very useful to improve the production of high-performance seeds. 相似文献
139.
140.
不同温度条件下水稻种子活力QTL的定位分析 总被引:6,自引:0,他引:6
为了揭示基因型与环境温度之间的互作对种子活力的影响,利用1个粳籼交来源的重组自交系群体,采用纸卷法在15、20和25℃条件下进行发芽试验,考察了发芽率、芽长、根长及干重等4个种子活力相关性状。结合一张含有198个DNA标记的连锁图谱,用作图软件QTL Mapper1.0定位与种子活力相关的QTL。共检测到34个主效应QTL。这些QTL中的绝大多数(82%)成簇分布于第3、5和8号染色体的5个不同染色体区段上,分别被命名为QTL qSV-3-1、qSV-3-2、qSV-5、qSV-8-1和qSV-8-2。其中,QTL qSV-3-1、qSV-3-2和qSV-8-1对种子活力的效应大小和方向在3个温度条件下均较一致;而QTL qSV-5和qSV-8-2主要在20和25℃条件下起作用,在15℃低温条件下作用甚微或不起作用。表明种子活力QTL具有显著的基因型与环境温度之间的互作,而且这种互作具有明显的QTL特异性。芽长是唯一同时受5个与种子活力高度相关的染色体区段共同影响的指标,因此,相对而言,作为水稻种子活力的测定指标,芽长是最具有代表性的。 相似文献