Biology Assignment 代写: 牡丹花牡丹

Biology Assignment 代写: 牡丹花牡丹

Biology Assignment 代写:  牡丹花牡丹

牡丹牡丹原产于中国,是一个伟大的、美丽的和有吸引力的观赏植物(Wister,1995)。牡丹已成为现代社会的织物之一,是最重要的园林植物之一(三十)。它被广泛种植在亚洲,美国,欧洲和澳大利亚的大陆(三十)。牡丹是一种优秀的观赏植物,在中国社会经济、文化和药用的内涵(XXX)。

绰号为“花之王”在中国的文化,它象征着和平、幸福、繁荣、发展,在中国的权力和财富(XXX)。由于其极大的丰富的文化内涵,牡丹在中国广泛种植。事实上,在中国有丰富的牡丹种及品种的国家尽管很大程度上缺乏连续二次开花品种,花一年两次或更多(XXX)。因此,遗传工程或强迫开花(诱导秋季甚至冬季开花)可以带来巨大的好处,园艺产业在中国。

牡丹栽培中的花期调控和发育机理的研究是很重要的,因为大田花卉不仅一年一次,而且花期也很短。与牡丹花有关的高需求和价格价值,使这一观赏植物的研究更为理想(三十)。牡丹通常需要3â€5年开始开花。即使如此,叶子和花也有相同的芽,植物每年只收获一次(三十)。受经济利益的驱动,质量和数量的花,因此在牡丹栽培overridingly重要(XXX)。了解强制连续二次开花的生理机制,因此是一种很有前途的替代在园艺业的牡丹花。

内源性(如糖、基因和激素水平)和外源性(例如,一天的长度和温度)的生理因素的影响,花卉生产在顶端分生组织(XXX)。从青少年到成人阶段的过渡是严重影响环境因素的变化。这些因素反过来影响血糖和激素水平,因此牡丹植物花卉生产(zeevart,1979)。牡丹需要一段时间的低温发芽生长之前,花和茎生产。花蕾长出后夏季常年冠,从叶片衰老直到芽休眠(拜恩& Halevy,1986)。芽发育只有简历冬天冷春化后(拜恩:,1986;富尔顿等,2001;哈勒维et al.,2002;Kamenetsky等,2003)。一些牡丹品种如敖双,然而,不遵循这个程序,所以花在夏天不冷春化(XXX)。

牡丹,像任何其他开花植物,需要激素的生长和生理生化过程的正常维持。激素是植物发育过程中的关键性物质,在植物发育过程中是至关重要的。激素调节根系发育,血管分化,对气候变化的响应,顶端优势,花的发育和胚胎发育(弗里姆尔,2003;卡蒂娅&吉尔伯托,2004;安娜et al.,2004;刘等,2008)。激素,但是效果,今年不同季节时期的环境条件的变化(koshita et al,1999)。例如,奥特曼和格伦(1972)指出,IAA、GA和ABA分别增强和抑制延迟,夏芽萌发。最近的研究表明,随着季节不同植物器官改变细胞分裂素公司(XXX)。顶芽高加索冷杉细胞分裂素水平在六月中旬最低和最高在夏末。亚顶芽,细胞分裂素在六月最低和最高的中秋,但水平比顶芽低得多(拉斯姆森等,2009)。此外,外源IAA、ABA的抑制作用,并在牵牛内源IAA诱导外源GA强迫开花(wijayanti et al.,1997)。

和激素一样,植物的生长和发育也受到有效的营养素的影响。有研究表明,蔗糖、葡萄糖和果糖构成主要吸收大部分的植物(XXX)。Sucrose是在用氨基酸合成的能源和碳骨架植物碳水化合物的主要形式,脂类代谢产物(黑尔特和Heldt,2005)。开花也与糖水平的变化有关。可溶性糖含量可以改变,以调节植物生长过程。糖分积累水平已经注意到在木本植物组织在应对季节变化(Li et al.,1965;索特和kloth,1987;Nelson & Dickson,1981)。例如,当糖发生在冬天,去适应导致弹簧低水平(Parker,1962;FeGe & Brown,1984;bonicel et al.,1987)。

了解激素变化和相关的花芽发展,可以合理地转化牡丹花的生产。秋季相对较少的研究

Tree peony Paeonia suffruticosa is one of the most widely cultivated ornamental plants in the world. Successive secondary flowering in autumn season is critical for some ornamental plant production, including tree peony. Varying levels of hormones and sugars influence autumn flowering in tree peony. This study analysis quantitative changes in endogenous hormone (IAA, ABA & GA3) and sugar (sucrose, reducing sugars & starch) levels in bud samples of ‘Ao-Shuang’ tree peony cultivar during autumn and spring flowering. The levels of hormones and carbohydrates in spring and autumn flowing are notably different. For both seasons, sucrose concentration is highest, then followed by reducing sugars and starch. Whereas sucrose and reducing sugar content increases in autumn, that of starch decreases. A similar trend is also noted for the spring season plant. High concentrations of IAA, GA3 are observed along with low concentrations of ABA in autumn flowering tree peony. Although quantitative changes in endogenous hormones and carbohydrates could variously influence tree peony flowering, the observed mix could enhance tree peony flowering mechanism.

Keywords: Tree peony, autumn/spring flowering, ornamental plant, hormone, sugar

Introduction

Paeonia suffruticosa tree peony is native to China and is a magnificent, beautiful and attractive ornamental plant (Wister, 1995). Tree peony has made its way into the fabrics of modern society as one of the most important garden plants (XXX). It is widely cultivated in the continents of Asia, America, Europe and Australia (XXX). Tree peony is an excellent ornamental plant with soco-economic, cultural and medicinal connotations in China (XXX).

Nicknamed as the “King of flowers” in China, it culturally symbolizes peace, happiness, prosperity, development, power and wealth in China (XXX). Because of its vastly rich cultural connotation, tree peony is extensively cultivated in China. In spite of the fact that there are abundant tree peony species and cultivars in China, the country largely lacks successive secondary flowering cultivars that flower two or more times in the year (XXX). Hence genetic engineering or forced-flowering (that induces autumn or even winter flowering) could bring tremendous benefits to the industry of horticulture in China.

The study of flowering control and development mechanisms in tree peony cultivation is important because the field plants flower not only once in the year, but also have short flowering periods. The high demands and price values associated with tree peony flower make research on this ornamental plant even more desirable (XXX). Tree peonies normally take 3‒5 years to start flowering. Even so, leaves and flowers share the same bud and the plant is harvested only once a year (XXX). Driven by economic benefits, the quality and quantity of flowers are therefore overridingly important in tree peony cultivation (XXX). Understanding the physiological mechanisms of forced successive secondary flowering is therefore a promising alternative in the horticultural industry of tree peony.

Several endogenous (e.g., levels of sugars, genes & hormones) and exogenous (e.g., day length & temperature) physiological factors influence flower production in apical meristems (XXX). The transition from juvenile to adult phases is heavily influenced by changes in environmental factors. These factors in turn influence sugar and hormone levels, hence flower production in peony plants (Zeevart, 1979). Tree peonies require a period of cool temperature prior to bud growth, flower and shoot production. The flower buds grow out on perennial crowns in later summer, starting from leaf senescence till bud dormancy (Byrne & Halevy, 1986). Bud development then only resumes after winter cold vernalization (Byrne & Halevy, 1986; Fulton et al., 2001; Halevy et al., 2002; Kamenetsky et al., 2003). Some tree peony cultivars such as Ao-Shuang, however, do not follow this routine and therefore blossom in summer without cold vernalization (XXX).

Peony, like any other flowering plant, requires hormones for growth and normal maintenance of physiological and biochemical processes. As growth-regulating organic substances, hormones are critical in plant developmental processes. Hormones regulate root development, vascular differentiation, response to climate, apical dominance, flower development and embryogenesis (Friml, 2003; Katia & Gilberto, 2004; Ana et al., 2004; Liu et al., 2008). The effects of hormones, however, changes with environmental conditions in different periods/seasons of the year (Koshita et al, 1999). For instance, Altman & Goren (1972) noted that IAA, GA and ABA respectively delays, enhances and inhibits summer bud sprouting. Recent studies have shown that cytokinin profiles of different plant organs change with season (XXX). Cytokinin levels in apical buds of Abies nordmanniana are lowest in mid-June and highest in late summer. For sub-apical buds, cytokinin is lowest in June and highest in mid autumn, but with much lower levels than apical buds (Rasmussen et al., 2009). Furthermore, inhibitory effects of exogenous IAA, ABA, and endogenous IAA in Pharbitis nil induce exogenous GA-forced flowering (Wijayanti et al., 1997).

Like hormones, plant growth and development are also influenced by available nutrients. Studies have shown that sucrose, glucose and fructose constitute the main assimilates of most plants (XXX). Sucrose is the main form of plant carbohydrate for the energy and carbon skeletons used in the synthesis of amino acids, lipids and metabolites (Heldt & Heldt, 2005). Flowering too is associated with changes in sugar level. Soluble sugar levels can be altered to regulate plant growth processes. Accumulated sugar levels have been noted in woody plant tissues in response to seasonal variations (Li et al., 1965; Sauter & Kloth, 1987; Nelson & Dickson, 1981). For instance, while sugar occurs in winter, deacclimatization leads to low levels in spring (Parker, 1962; Fege & Brown, 1984; Bonicel et al., 1987).

Understanding hormonal changes and the associated floral bud developments could rationally transform tree peony flower production. There is relatively little research on autumn flowering of tree peonies (Jiang et al., 2007; Li, 1998; Xiao et al., 2001). Hardly is the effect of changes in endogenous hormones on tree peony flower production documented in the literature. Least documented are endogenous hormone and sugar variations in flowering tree peonies with spring and autumn seasons. The research task of this study was to determine the dynamics of endogenous hormone and sugar levels in flowering Ao-Shuang tree peony cultivar in spring and autumn seasons.

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