权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Proanthocyanidins in Cereals and Brassicaceae: A Cross-Species Approach on their Roles for Seed-Coat Biophysical Properties, Dormancy and Germination

谷物和十字花科中的原花青素：跨物种方法研究其对种皮生物物理特性、休眠和发芽的作用

基本信息

批准号：
BB/M000583/1
负责人：
Gerhard Leubner
金额：
$ 87.71万
依托单位：
Royal Holloway University of London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2015
资助国家：
英国
起止时间：
2015 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FM000583%2F1
关键词：
Proanthocyanidins Cereals Brassicaceae Cross Species

项目摘要

Seeds are at the beginning and end of the life cycle of all higher plants. Many wild species show a high degree of dormancy that prevents seeds from germinating immediately after shedding, and delays germination until more favourable conditions for plant growth are encountered. Domestication of crop plants from such wild species has often resulted in significant loss of dormancy as prehistoric farmers selected in favour of seeds with rapid germination. However, some degree of dormancy is an important quality trait in many crops, as it prevents seeds from germinating prematurely while still attached to the mother plant. This is a serious problem in cereals such as bread wheat, because wet weather near harvest time can cause seeds to germinate within the ear ("pre-harvest sprouting"). This causes release of enzymes that partially degrade of the starch (flour) and thereby impacts negatively on bread-making quality. Sprout-induced seeds produce so much enzyme that a small proportion of such grains within a crop can result in the entire harvest being suitable only as animal feed, with consequent economic loss to the farmer.Thus, too little dormancy can result in pre-harvest sprouting, while too much dormancy may lead to non-uniform germination in the field. This is important for high-quality seeds also of broadleaf crop species from the cabbage family (Brassicaceae). The speed and uniformity of germination of crop seeds after sowing is an equally important seed quality trait and together with dormancy directly affects crop production. Clearly, an understanding of the processes that determine the level of dormancy and the speed of germination are essential to enable us to design and breed new varieties of crop plants which perform well even in stressful environments (under climate change). One clear contributory factor in many species is the seed coat, damage to which or removal can result in complete loss of dormancy and in faster germination. This appears to be associated with the presence of reddish-brown tannins in the seed coat; the importance of these seed coat tannins is clear from plants that have lost the ability to make the compounds, resulting in pale-coloured seeds with lower levels of dormancy and faster germination. For example, white-grained wheat is much more prone to pre-harvest sprouting than a red-grained variety and is therefore difficult to grow successfully in the wet UK climate. White-grained wheat has several advantages over red-grained types, including a higher yield of white flour and the production of "white wholemeal" with the taste of white bread but the fibre and nutrient properties of normal red wholemeal.There are several ways in which the tannins in the seed coat could affect dormancy and germination: they may increase the physical strength of the coat to prevent germination, they may affect the permeability of the coat to water, hormones or oxygen, which are required for germination, or precursors or metabolites of the tannins might directly suppress seed germination. These different hypotheses have not previously been directly tested, but our collaborative team has developed the materials and the methods through which we can examine each in turn. We plan to look at two species, cress and wheat, as models for eudicot (broadleaf) and monocot (cereal) species, respectively. We have developed varieties of both species that are impaired in the late steps in tannin production in the seed coat, so that we can examine the effects on tannins for seed coat properties, on dormancy and the speed of germination. At the same time we have pioneered methods for measuring the strength, extensibility and permeability of the isolated seed coats. We will relate these properties to the interaction with environmental factors such as temperature, to provide a comprehensive understanding of the roles of tannins in coat-imposed dormancy and germination speed of seeds.

种子是所有高等植物生命周期的起点和终点。许多野生物种表现出高度休眠，这阻止种子在脱落后立即发芽，并延迟发芽，直到遇到更有利的植物生长条件。从这些野生物种驯化农作物常常导致休眠的显著丧失，因为史前农民选择了发芽迅速的种子。然而，在许多作物中，一定程度的休眠是一个重要的品质性状，因为它可以防止种子在仍附着在母体植株上时过早发芽。这在面包小麦等谷物中是一个严重的问题，因为接近收获季节的潮湿天气会导致种子在穗内发芽（“收获前发芽”）。这会导致酶的释放，使淀粉（面粉）部分降解，从而对面包的制作质量产生负面影响。发芽诱导的种子产生如此多的酶，以至于作物中这种谷物的一小部分可能导致整个收获只适合作为动物饲料，从而给农民带来经济损失。因此，休眠过少会导致收获前发芽，而休眠过多则可能导致田间发芽不均匀。这对白菜科（芸苔科）阔叶作物的优质种子也很重要。作物种子播种后发芽的速度和均匀性是一项同样重要的种子品质性状，与休眠一起直接影响作物产量。显然，了解决定休眠水平和发芽速度的过程对于我们设计和培育即使在压力环境下（在气候变化下）也能表现良好的农作物新品种至关重要。在许多物种中，一个明显的促成因素是种皮，种皮的损坏或去除会导致完全失去休眠和更快的发芽。这似乎与种皮中存在的红褐色单宁有关；这些种皮单宁的重要性很明显，因为植物已经失去了制造这种化合物的能力，导致种子颜色苍白，休眠时间较短，发芽速度更快。例如，白粒小麦比红粒小麦更容易在收获前发芽，因此很难在潮湿的英国气候中成功种植。白粒小麦比红粒小麦有几个优点，包括白面粉产量更高，生产的“白色全麦”具有白面包的味道，但纤维和营养特性与普通红色全麦相同。种皮中的单宁对种子休眠和萌发的影响主要有以下几种：增加种皮的物理强度以阻止种子萌发；影响种皮对发芽所需的水分、激素或氧气的渗透性；单宁的前体或代谢物直接抑制种子萌发。这些不同的假设以前没有被直接测试过，但是我们的合作团队已经开发了材料和方法，通过这些材料和方法我们可以依次检查每一个假设。我们计划分别以甘蓝和小麦两种植物作为双叶植物（阔叶植物）和单叶植物（谷物）的模型。我们已经开发了两个物种在种皮中单宁生产的后期阶段受损的品种，以便我们可以研究单宁对种皮特性，休眠和发芽速度的影响。同时，我们开创了测量分离种皮的强度、延伸性和渗透性的方法。我们将把这些特性与环境因素（如温度）的相互作用联系起来，以全面了解单宁在包衣休眠和种子萌发速度中的作用。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Cold-induced secondary dormancy and its regulatory mechanisms in Beta vulgaris.

DOI：
10.1111/pce.14264
发表时间：
2022-04
期刊：
PLANT CELL AND ENVIRONMENT
影响因子：
7.3
作者：
Hourston, James E.;Steinbrecher, Tina;Chandler, Jake O.;Perez, Marta;Dietrich, Katrin;Tureckova, Veronika;Tarkowska, Danuse;Strnad, Miroslav;Weltmeier, Fridtjof;Meinhard, Juliane;Fischer, Uwe;Fiedler-Wiechers, Karin;Ignatz, Michael;Leubner-Metzger, Gerhard
通讯作者：
Leubner-Metzger, Gerhard

Encyclopedia of Applied Plant Sciences

应用植物科学百科全书