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  • Author: S.H. Zhang x
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Open access

H. Han, X. M. Sun, Y. H. Xie, J. Feng and S. G. Zhang

Abstract

Adventitious root development is crucial for cutting propagation in hybrid larch. In the present study, semilignified cuttings of Larix kaempferi × L. olgensis clones were used to study the morphological and anatomical changes during the different development stages and compare the changes in contents of endogenous phytohormone in two clones with evidently different rooting capacity (25-5 and 23-12), and the effects of exogenous Indole-3-Butyric Acid (IBA) on phytohormone content of a very low native rooting capacity clone (8-9) during the development of adventitious roots. The results showed that the development of adventitious root in semi-lignified cuttings involves three key stages: root cell dedifferentiation and division (14-18 DAC); meristem formation and development (25-35 DAC); root formation and elongation (50-55 DAC). The endogenous phytohormones play a key role during adventitious root development. For 25-5 and 23-12, the level of endogenous phytohormones, especially the ABA content, has an important effect on rooting capacity. For the effects of IBA on 8-9, except lower ABA content, the temporary peak of IAA on the 1 DAC was important for initiating the rooting process. The ratio of (IAA + GA3 + ZR)/ABA can be used as an indicator of rooting capacity. The anatomical and physiological data described here for semi-lignified cuttings of L. kaempferi × L. olgensis clones improves our knowledge of adventitious roots development. Our study will also benefit future research on examining the molecular mechanisms of the adventitious roots development in hybrid larch.

Open access

H.S. Tian, B.H. Zhang, S.H. Zhang and M.Y. Lü

Abstract

The Yishu Fault Zone runs through the centre of Shandong Province (E China); it is a deep-seated large fault system that still is active. Two volcanic faulted basins (the Shanwang and Linqu Basins) in the Linqu area, west of the fault zone, are exposed to rifting, which process is accompanied by a series of tectonic and volcanic earthquakes with a magnitude of 5-8. Lacustrine sediments in the basins were affected by these earthquakes so that seismites with a variety of soft-sediment deformation structures originated. The seismites form part of the Shanwang Formation of the Linqu Group. Semi-consolidated fluvial conglomerates became deformed in a brittle way; these seismites are present at the base of the Yaoshan Formation. Intense earthquakes triggered by volcanic activity left their traces in the form of seismic volcanic rocks associated with liquefied-sand veins in the basalt/sand intercalations at the base of the Yaoshan Formation. These palaeo-earthquake records are dated around 14-10 Ma; they are responses to the intense tectonic extension and the basin rifting in this area and even the activity of the Yishu Fault Zone in the Himalayan tectonic cycle.

Open access

Y. H. Li, X. Y. Kang, S. D. Wang, Z. H. Zhang and H. W. Chen

Abstract

Efficient methods for obtaining unreduced female gametes are needed for triploid induction in Populus alba x P. glandulosa. A cytological study of MMCs and PMCs meiosis and staminate floral elongation revealed that there was a close association between MMCs meiotic stage and male bud phenology during development under the same environment conditions. Female buds of Populus alba x P. glandulosa were treated with 0.5% colchicine solution at the selected meiotic stages based on male bud phenology. The treated buds were pollinated with pollen of P. tomentosa. A high rate of unreduced female gametes occurred in late leptotene and pachytene stages of MMC, as evidenced by a relatively higher percentage of triploids in the progeny, when compared to progeny from colchincine application at other meiotic stages. The present results demonstrated that male bud phenology can be used to guide colchicine applications to female buds and cause a more efficient production of triploids.

Open access

B. Zhou, D. Zhang, S. M. Pei, H. Zhang, H. C. Du, Y. P. Jin and D. G. Lin

Abstract

Canine mammary tumors are the most common neoplasms in intact female dogs. The surgery cannot always solve the problem, chemotherapy are recommend to these patients. However, chemotherapy could always fail because of multidrug resistance (MDR). Through stepwise increasing 5-Fluorouracil (5-FU) concentration in the culture medium, a 5-FU-resistant canine mammary tumor cell line CMT7364/5-FU was established to disclose the molecular mechanism of the drug resistance. Cell morphology, cell sensitivity to drugs, growth curves, expression of proteins, and chemo-sensitivity in vivo were compared between the parental cell line and resistant cell line. As compared it to its parental cell line (CMT7364), CMT7364/5-FU showed different morphology, cross-resistant to other chemo-drugs and a prolonged population doubling time (PDT). The drug efflux pump proteins (ABCB1 and ABCG2) in CMT7364/5-FU were up-regulated. In vivo, the similar result revealed that CMT7364/5-FU cell line was more resistant to 5-FU. In conclusion, a 5-FU-resistant canine mammary tumor cell line (CMT7364/5-FU) was successfully established, it can serve as a good model for researching the mechanism of MDR and screening effective agents to reverse drug resistance.

Open access

L. Zhang, N. Huanqiong, Washington J. Gapare, S. K. Dillon, X. Li and H. X. Wu

Abstract

Genetic diversity within radiata pine first generation of open-pollinated selections (OPS) from the native resource stands was compared with that observed in native populations to monitor potential changes in genetic diversity during domestication. Genetic diversity was estimated using 58 single nucleotide polymorphisms (SNPs) from 8 expressed genes. Nucleotide diversity maintained in first generation of selections (OPS) (mean π = 0.0036; mean θw = 0.0058) was similar to that found within the native population material (mean π = 0.0043; mean for θw = 0.0065). Likewise, mean values for expected heterozygosity (HE) within and between native population material and OPS were similar (mean = 0.27 ± 0.04) and not significantly different (P = 0.068). Also, the overall distribution of allele frequency classes was not significantly different between native population material and OPS. These results point to no evidence of loss of diversity in OPS due to artificial selection. One possible reason is that the domestication of the OPS is at a very early stage. Another may be that artificial selection in the OPS was based on tree growth and form, not wood properties. The genes selected in this study are mostly involved in cell wall formation, thus genetic diversity of these genes should remain stable between natural population and OPS, unless there was a significant sampling bias in the OPS. Although the SNP information suggests similarities among mainland populations, results from quantitative genetic studies found large provenance differences for growth-, morphological-, stem-form traits, and disease resistance. Determining the threshold at which genetic diversity levels will be significantly reduced during selection should help breeders to make informed decisions regarding the intensity of selection in managed breeding populations as well as gene resource populations.

Open access

L. H. Zeng, Q. Zhang, B. X. He, H. M. Lian, Y. L. Cai, Y. S. Wang and M. Luo

Abstract

Masson pine (Pinus massoniana Lamb) has long been employed as a main source of pine resin in China. To get a better understanding of genetic regulation of resinyielding capacity (RYC), a total of 50 open-pollinated families of masson pine were planted at three testing sites for progeny testing. Investigation was conducted at ages 7, 9, 11, 13, 15, 20, 24 and 26 years to study inheritance, age-age genetic correlation, and early selection efficiency for RYC, height (HT), diameter at breast height (DBH) and volume of individual tree (VOL). Growth characteristics increased gradually with age. RYC had a rapid increase at early ages (before age 15) ficients of variations (CV) for four traits showed a decreasing trend with age and the decreasing rate was rapid at early ages and minor at later ages. Heritability for four traits was relatively stable with minor fluctuation. For across-age classes, heritability was the highest for height, intermediate for RYC, and lowest for volume and DBH. RYC had highly positive genetic correlations with three growth characteristics. Genotype-by-environment interaction for four traits was stronger at Yunan than at other testing sites. Age-age genetic correlations were high for four traits studied, reaching 0.7 after age 9 for most analyses. Early selection at age 13 was highly effective for height, age 15 for DBH and volume, and age 11 for RYC.

Open access

B. Zhang, H. Wagner, M. Büchsenschütz-Göbeler, Y. Luo, S. Küchemann, W. Arnold and K. Samwer

Abstract

For the past two decades, atomic force acoustic microscopy (AFAM), an advanced scanning probe microscopy technique, has played a promising role in materials characterization with a good lateral resolution at micro/nano dimensions. AFAM is based on inducing out-of-plane vibrations in the specimen, which are generated by an ultrasonic transducer. The vibrations are sensed by the AFM cantilever when its tip is in contact with the material under test. From the cantilver’s contactresonance spectra, one determines the real and the imaginary part of the contact stiffness k*, and then from these two quantities the local indentation modulus M' and the local damping factor Qloc -1 can be obtained with a spatial resolution of less than 10 nm. Here, we present measured data of M' and of Qloc -1 for the insulating amorphous material, a-SiO2. The amorphous SiO2 layer was prepared on a crystalline Si wafer by means of thermal oxidation. There is a spatial distribution of the indentation modulus M' and of the internal friction Qloc -1. This is a consequence of the potential energy landscape for amorphous materials.