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1.

类叶升麻具有毛茛科中最对称和最原始的核型吗? 总被引：4，自引：0，他引：4

杨亲二《中国科学院研究生院学报》1998,36(6):490-495

根据以前的报道,类叶升麻 Actaea asiatica Hara具有10条大型的中部着丝点染色体和6条较大的近中部着丝点染色体,其核型在毛茛科中显得最为对称和原始,而类叶升麻属的其他种类具有10条大型的中部着丝点染色体、4条较大的近中部着丝点染色体和两条没有短臂的染色体。在毛茛科中,同一属的染色体形态通常十分相似,因此上述类叶升麻的核型分析结果十分可疑。本文重新检查子该种的染色体。结果表明其核型与该属其他种类的核型没有明显区别。与升麻属其他4属,即 Beesia, Anemonopsis,Souliea,Cimicifuga相比,类叶升麻及该属其他种类都具有两条没有短臂的T染色体,因此类叶升麻属 Actaea L．的核型不对称性程度在升麻族中显得最高,其核型在该族中也可能最为进化, 这两条T染色体可以作为类叶升麻属的细胞学标志,据此可以将该属与升麻族其他4属区别开来。相似文献

2.

单穗升麻的柱头和雌配子体发育及胚胎发生

陈晓麟李铭尤瑞麟《中国科学院研究生院学报》2000,38(4):337-342

单穗升麻的雌蕊群由1～5枚离生心皮组成。子房单室,4～9枚倒生胚珠,双珠被,厚珠心;大孢子四分体呈线形或T形排列,合点端一个具功能。胚囊发育为蓼型。成熟胚囊中3个单核反足细胞,胞质浓密,在球形胚时期尚能观察到其退化痕迹。极核融合早,次生核位于合点端。胚胎发生为柳叶菜型;核型胚乳。雄蕊凋谢后1～2天花柱顶端腹缝线周围出现乳突细胞,雄蕊凋谢后3～5天延长成柱头毛。讨论了单穗升麻与南川升麻柱头可授期与花粉生活力的差异对传粉效果和结籽率的显著影响。相似文献

3.

铁破锣属的系统位置——ITS(nrDNA)序列证据

汪小全邓峥嵘洪德元《中国科学院研究生院学报》1998,36(5):403-410

对Beesia calthifolia等5种金莲花亚科植物的核糖体DNA中的内转录间隔区(ITS)序列及5．8S rRNA基因的3′端序列进行了测定。这几种金莲花亚科植物的ITS-1的长度范围为225～232 bp,ITS-2 的长度范围为201～217 bp。B．calthifolia的ITS-1(227 bp)和ITS-2(215 bp)的长度及序列均与升麻属及类叶升麻属植物相近,其5.8S rRNA基因的3′端序列也近乎与升麻属及类叶升麻属植物完全一致 (仅一个碱基缺失的差异),但其在上述几方面均与金莲花属植物相差甚远。以Ranunculus enysii作为外类群,运用PAUP软件进行的系统发育分析表明:B．calthifolia,Cimicifuga acerina,C．brachycarpa 和Actaea asiatica形成一个单系群,并得到bootstrap分析的极强支持,B．calthifolia位于这一单系群的基部。这一DNA序列分析结果与来自植物化学、孢粉学和细胞学的研究结果相吻合,更进一步支持铁破锣属是升麻族的自然成员,并可能是升麻族中一个最原始的类群。相似文献

4.

抗肿瘤药物研究取得新进展

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《中国科学院院刊》2010,(3):349-349

升麻是我国著名的中药。同属植物黑升麻,在欧美国家也有很长的使用历史。近10年来美国黑升麻干燥根茎用于作为治疗更年期综合症的补充剂的交易量达每年10亿美元左右。我国升麻属植物资源丰富,广泛分布于全国各地,但对其的开发利用却极不合理：一般只在民间少量用做治头痛牙痛、咽喉痛等疾病,或是以粗提物的形式卖到国外公司。相似文献

5.

毛茛科金莲花族和升麻族细胞学的比较研究

杨亲二《中国科学院研究生院学报》2002,40(1):52-65

对毛茛科金莲花族Trolliese和升麻族Cimicifugeae的细胞学进行了比较研究。发现驴蹄草Caltha palustris L．在云南西北部形成一个多倍体系列(2n=32，48，64)，四倍体细胞型(2n=4x=32)较为常见，其核型有明显的居群间变异。驴蹄草属Caltha、鸡爪草属Calathodes、Megaleranthis以及金莲花属Trollius的染色体在大小上基本相似，都属于中等大小的R-型染色体。细胞学和花粉学证据都支持鸡爪草属与Megaleranthis和金莲花属有较近的亲缘关系。铁破锣属Beesia、Anemonopsis、黄三七属Souliea、升麻属Cimicifuga以及类叶升麻属Actaea的核型彼此基本相似，在染色体大小和形态上都与驴蹄草属、鸡瓜草属、Megaleranthis以及金莲花属的核型明显有别。细胞学证据表明铁破锣属应是升麻族中的成员。相似文献

6.

Stability analysis of continuous-time systems with time-varying delay using new Lyapunov–Krasovskii functionals

Jun Chen Ju H. Park Shengyuan Xu 《Journal of The Franklin Institute》2018,355(13):5957-5967

This paper studies the stability of linear continuous-time systems with time-varying delay by employing new Lyapunov–Krasovskii functionals. Based on the new Lyapunov–Krasovskii functionals, more relaxed stability criteria are obtained. Firstly, in order to coordinate with the use of the third-order Bessel-Legendre inequality, a proper quadratic functional is constructed. Secondly, two couples of integral terms

{\int_{t ? h_{t}}^{s} x (s) d s, \int_{s}^{t} x (s) d s}

and

{\int_{t ? h_{M}}^{s} x (s) d s, \int_{s}^{t ? h_{t}} x (s) d s}

are involved in the integral functionals

\int_{t ? h_{t}}^{t} (\cdot) d s

and

\int_{t ? h_{M}}^{t ? h_{t}} (\cdot) d s,

respectively, so that the coupling information between them can be fully utilized. Finally, two commonly-used numerical examples are given to demonstrate the effectiveness of the proposed method. 相似文献

7.

Chaotic behavior of discrete-time linear inclusion dynamical systems

Xiongping Dai Tingwen Huang Yu Huang Yi Luo Gang Wang Mingqing Xiao 《Journal of The Franklin Institute》2017,354(10):4126-4155

Given any finite family of real d-by-d nonsingular matrices

{S_{1}, \dots, S_{l}},

by extending the well-known Li–Yorke chaos of a deterministic nonlinear dynamical system to a discrete-time linear inclusion or hybrid or switched system:

\begin{matrix} x_{n} \in {S_{k} x_{n ? 1}; 1 \leq k \leq l}, x_{0} \in R^{d} and n \geq 1, \end{matrix}

we study the chaotic dynamics of the state trajectory (x_n(x₀, σ))_{n ≥ 1} with initial state

x_{0} \in R^{d},

governed by a switching law

σ : N \to {1, \dots, l}

. Two sufficient conditions are given so that for a “large” set of switching laws σ, there exhibits the scrambled dynamics as follows: for all

x_{0}, y_{0} \in R^{d}, x_{0} \neq y_{0},

\begin{matrix} \underset{n \to + \infty}{lim inf} ∥ x_{n} (x_{0}, σ) ? x_{n} (y_{0}, σ) ∥ = 0 and \underset{n \to + \infty}{lim sup} ∥ x_{n} (x_{0}, σ) ? x_{n} (y_{0}, σ) ∥ = \infty . \end{matrix}

This implies that there coexist positive, zero and negative Lyapunov exponents and that the trajectories (x_n(x₀, σ))_{n ≥ 1} are extremely sensitive to the initial states

x_{0} \in R^{d}

. We also show that a periodically stable linear inclusion system, which may be product unbounded, does not exhibit any such chaotic behavior. An explicit simple example shows the discontinuity of Lyapunov exponents with respect to the switching laws. 相似文献

8.

The Gray image of a class of constacyclic codes over polynomial residue rings

《Journal of The Franklin Institute》2014,351(12):5467-5479

相似文献

9.

Uniform exponential stability of periodic discrete switched linear system

Akbar Zada Bakht Zada Jinde Cao Tongxing Li 《Journal of The Franklin Institute》2017,354(14):6247-6257

Let {Π_τ(m, n): m?≥?n?≥?0} be the family of periodic discrete transition matrices generated by bounded valued square matrices Λ_τ(n), where

τ : [0, 1, 2, ?) \to Ω

is an arbitrary switching signal. We prove that the family {Π_τ(m, n): m?≥?n?≥?0} of bounded linear operator is uniformly exponentially stable if and only if the sequence