白藜芦醇生物学活性研究进展

白藜芦醇是一种植物抗毒素,主要存在于虎杖、葡萄及花生等有限的植物中,它具有对人体有益的生物学活性,如具有拮抗肿瘤作用、心血管保护作用、抗炎作用、抗病毒作用、神经保护作用、植物雌激素作用和对骨钙的影响等。     

植物内生放线菌功能及生物活性物质研究进展

植物内生放线菌是与宿主植物存在互利共生关系的一类特殊微生物,具有丰富的生物学功能,能产生许多具有应用潜力的生物活性物质。阐述了植物内生放线菌与宿主植物之间的关系,并从提高宿主植物抗逆性、促进生长和生物固氮作用三个方面总结了植物内生放线菌的生物学作用研究进展;综述了植物内生放线菌产生的抗生素、酶和抗肿瘤活性物质以及这些物质在农业、医药以及食品行业中的应用前景。最后就内生放线菌生物学作用及活性物质研究中存在的问题和发展趋势进行了展望。     

植物组蛋白变体生物学功能

组蛋白变体是重要的表观遗传调控因子,能够在染色质特定位置替换常规组蛋白,维持染色质结构进而保证转录激活或抑制的顺利进行。目前,组蛋白变体的调控功能已成为植物学研究领域的一个热点。近年来,随着植物组蛋白变体生物学功能研究的不断深入,发现组蛋白变体能够在植物生长发育和环境应答调控等多个生物学过程中发挥重要作用。该文简要介绍了已知的植物组蛋白变体的种类,系统综述了各类组蛋白变体在植物多个生命进程中的生物学功能及调控过程,以期为深入认知植物组蛋白变体的作用机制提供参考。     

植物合成生物学领域发展态势的文献计量分析

合成生物学作为一种颠覆性技术可应用于农业领域的创新发展,解决当前农业学科中的瓶颈问题。利用文献计量学方法从领域发表论文的时序数量分布、主题分布等探测当前合成生物学的基本态势。基于领域的主题分布可知,其中植物合成生物学这一主题是稳定存在的且主题规模处于稳定增长趋势。聚焦植物合成生物学这一主题方向,在构建引文网络的基础上利用主路径分析方法从知识流动角度探测植物合成生物学领域重要知识节点,内容涵盖介子油苷生物合成途径,重要催化酶功能解析、转录因子的调控作用,组学方法的应用,利用微生物酵母进行生物物质合成,这些内容表征了合成生物的核心理论技术。     

植物合成生物学领域发展态势的文献计量分析

合成生物学作为一种颠覆性技术可应用于农业领域的创新发展,解决当前农业学科中的瓶颈问题。利用文献计量学方法从领域发表论文的时序数量分布、主题分布等探测当前合成生物学的基本态势。基于领域的主题分布可知,其中植物合成生物学这一主题是稳定存在的且主题规模处于稳定增长趋势。聚焦植物合成生物学这一主题方向,在构建引文网络的基础上利用主路径分析方法从知识流动角度探测植物合成生物学领域重要知识节点,内容涵盖介子油苷生物合成途径,重要催化酶功能解析、转录因子的调控作用,组学方法的应用,利用微生物酵母进行生物物质合成,这些内容表征了合成生物的核心理论技术。     

《植物细胞培养工程》

本书主要阐述了植物细胞培养基本技术、有工业价值的植物细胞的筛选、植物细胞培养过程中的生物学特征与技术需求、诱导子的作用、植物细胞反应器的操作与设计、植物细胞固定化与固定化细胞反应器、植物细胞培养的规模放大以及植物细胞培养的应用领域等内容．本书以现代细胞培养技术和工程原理为基础,紧紧围绕植物细胞培养过程中的关键工程技术和生物学需要,     

整体透明技术在植物生物学中的应用实例及其剖析

通过采用不同的透明剂和透明方法,对番茄（Lycopercicon esculenturm）侧根原基、加拿大一枝黄花（Solidago canadensis）与一枝黄花（S．decurens）的亲和性识别反应和苏门白酒草（Conyza sumatrensis）的胚珠发育过程进行了观察,提供了整体透明技术在植物生物学中的应用实例,简要回顾了该技术在植物生殖生物学中的应用和发展状况,分析了该技术在植物生物学应用中的优势和不足,探讨了该技术应用中一些具体的技术环节,如透明剂的选择和使用以及与特殊用途显微镜的配合使用等方面的问题,并对该技术的应用前景进行了展望。     

整体透明技术在植物生物学中的应用实例及其剖析

通过采用不同的透明剂和透明方法, 对番茄 (Lycopercicon esculentum)侧根原基、加拿大一枝黄花 (Solidago canadensis)与一枝黄花 (S. decurens)的亲和性识别反应和苏门白酒草 (Conyza sumatrensis)的胚珠发育过程进行了观 察, 提供了整体透明技术在植物生物学中的应用实例, 简要回顾了该技术在植物生殖生物学中的应用和发展状况, 分析了该技术在植物生物学应用中的优势和不足, 探讨了该技术应用中一些具体的技术环节, 如透明剂的选择和使用以及与特殊用途显微镜的配合使用等方面的问题, 并对该技术的应用前景进行了展望。     

改革植物生物学实验教学模式的探索与实践

植物生物学实验课是本科教学的重要内容。从植物生物学实验课的特点出发,在实验模块的选择、实验教学的方式和实验课要求等方面进行了改革尝试,在提高实验教学效果及加强学生动手能力方面发挥了较好的作用。     

植物几丁质酶及其在抗真菌病害中的应用

植物几丁质酶的研究是抗真菌基因工程的热点之一。几丁质酶能够水解真菌细胞壁的主要成分几丁质,在植物抗真菌病害反应中发挥重要的作用。介绍了几丁质酶的基本生物学特性、基因的诱导表达,并对植物几丁质酶基因在抗真菌病害基因工程中的应用进行了阐述。     

The Role of Calcium in the Fertilization Process in Flowering Plants

The fertilization process in flowering plants in a broad sense includes a progamic phase preceding the phase of double fertilization. To our present knowledge, calcium as a second messenger in the signal transduction plays important roles in all the links of this process. The present review attempts to highlight the recent advances in this research field, including: calcium in relation to in vitro pollen tube growth (distribution of calcium in pollen tube tip; regulation of pollen tube growth by calcium; calcium oscillation in pollen tube); distribution of calcium in pistil and its relation to in vivo pollen tube growth (calcium in relation to pollen-pistil recognition; pollen tube growth in pistil; pollen tube entry into embryo sac and the discharge and transportation of sperms); and calcium in relation to sperm-egg fusion and egg cell activation. In conclusion the author summarizes into several main view points, and gives recommendation for further researches on this topic.     

钙在被子植物受精过程中的作用

近年来,花粉管中的钙信号和生理功能的研究取得了明显的进展,同时在雌蕊系统中有关钙分布的研究也初步显示了其时、空特征与被子植物的受精作用密切相关。该文总结了花粉萌发和花粉管生长过程中外源钙和内源钙的作用机制,结合雌蕊组织中钙分布的特征,进一步探讨了钙在被子植物受精过程中的功能。     

From pollination to fertilization in fruit trees

The phase that elapses from pollination to fertilization is re-examined giving special attention to pollen pistil interaction in compatible matings. Pollination induces an activation of the pistil. A number of changes take place in the different tissues of this organ that appear to support male gametophyte development and to assist fertilization. Thus pollination induces stigma secretion, the release of starch from the transmitting tissue and prolongs embryo sac viability. It appears that even those pollen grains that do not achieve fertilization have a synergistic role supporting others to do so.The pistil also has an effect on pollen tube growth. Pollen tube growth along the pistil is not continuous, accelerations and decelerations take place depending on the different tissues they traverse. The fact that pollen tube growth is heterotrophic, at the expenses of the pistil reserves, and that these reserves are not continuously produced confers the pistil with a role controlling pollen tube growth kinetics.     

Calcium function and distribution during fertilization in angiosperms

Calcium has an essential signaling, physiological, and regulatory role during sexual reproduction in flowering plants; elevation of calcium amounts is an accurate predictor of plant fertility. Calcium is present in three forms: (1) covalently bound calcium, (2) loosely bound calcium typically associated with fixed and mobile anions (ionic bonding); and (3) cytosolic free calcium-an important secondary messenger in cell signaling. Pollen often requires calcium for germination. Pollen tube elongation typically relies on external calcium stores in the pistil. Calcium establishes polarity of the pollen tube and forms a basis for pulsatory growth. Applying calcium on the tip may alter the axis; thus calcium may have a role in determining the directionality of tube elongation. In the ovary and ovule, an abundance of calcium signals receptivity, provides essential mineral nutrition, and guides the pollen tube in some plants. Calcium patterns in the embryo sac also correspond to synergid receptivity, reflecting programmed cell death in one synergid cell that triggers degeneration and prepares this cell to receive the pollen tube. Male gametes are released in the synergid, and fusion of the gametes requires calcium, according to in vitro fertilization studies. Fusion of plant gametes in vitro triggers calcium oscillations evident in both the zygote and primary endosperm during double fertilization that are similar to those in animals.     

The pollen receptor kinase LePRK2 mediates growth-promoting signals and positively regulates pollen germination and tube growth

In flowering plants, the process of pollen germination and tube growth is required for successful fertilization. A pollen receptor kinase from tomato (Solanum lycopersicum), LePRK2, has been implicated in signaling during pollen germination and tube growth as well as in mediating pollen (tube)-pistil communication. Here we show that reduced expression of LePRK2 affects four aspects of pollen germination and tube growth. First, the percentage of pollen that germinates is reduced, and the time window for competence to germinate is also shorter. Second, the pollen tube growth rate is reduced both in vitro and in the pistil. Third, tip-localized superoxide production by pollen tubes cannot be increased by exogenous calcium ions. Fourth, pollen tubes have defects in responses to style extract component (STIL), an extracellular growth-promoting signal from the pistil. Pollen tubes transiently overexpressing LePRK2-fluorescent protein fusions had slightly wider tips, whereas pollen tubes coexpressing LePRK2 and its cytoplasmic partner protein KPP (a Rop-GEF) had much wider tips. Together these results show that LePRK2 positively regulates pollen germination and tube growth and is involved in transducing responses to extracellular growth-promoting signals.     

Heat stress-induced limitations to reproductive success in Gossypium hirsutum

Using in vitro systems, numerous authors have cited the sensitivity of pollen tube growth to high temperature as a major cause of low yields for crops with valuable reproductive structures. We investigated the hypothesis that in vivo fertilization efficiency would be negatively affected by heat stress-induced changes in energy reserves and calcium-mediated oxidative status in the pistil. Gossypium hirsutum plants exposed to optimal (30/20°C) or high day temperature (38/20°C) conditions during flowering were analyzed for fertilization efficiency via UV microscopic observation of pollen tube-containing ovules and for soluble carbohydrates, adenosine triphosphate (ATP), calcium, antioxidant enzyme activity and NADPH oxidase (NOX; EC 1.6.3.1) activity in the pistil. Leaf measurements included gas exchange, chlorophyll content, quantum efficiency and ATP content of the subtending leaf on the day of anthesis. In the pistil fertilization efficiency, soluble carbohydrates, ATP content and NOX activity declined significantly, whereas water soluble calcium and glutathione reductase (EC 1.8.1.7) activity increased, and superoxide dismutase (EC 1.15.1.1) activity remained unchanged. In leaves, heat stress decreased photosynthesis, quantum efficiency and chlorophyll content, but increased stomatal conductance. We conclude that decreased source leaf activity either inhibits pollen development, tube growth through the style or guidance to the ovules as a result of an insufficient energy supply to the developing pistil. We further conclude that a calcium-augmented antioxidant response in heat-stressed pistils interferes with enzymatic superoxide production needed for normal pollen tube growth and fertilization of the ovule.     

INFLUENCE OF THE PISTIL ON POLLEN TUBE KINETICS IN PEACH (PRUNUS PERSICA)

Pollen tube growth has been studied in peach and has been related to changes in the pistil structures which the pollen tube has to traverse in its way from the stigma down to the ovule. Growth of the pollen tubes along the pistil is not continuous. While pollen tubes reach the base of the style 7 days after pollination, fertilization does not take place until 12 days later. Pollen tubes stop for 5 days at the top of the obturator and they further stop for 3 days before entering the ovule. The pollen tube growth is heterotrophic; starch, present all along the pistilar tract at anthesis, vanishes as the pollen tubes pass by. Discontinuous pollen tube growth appears to be controlled by the pistil. At anthesis the pistil is not fully matured. Maturation of the pistil implies a number of secretory processes that occur in a basipetal way starting from the stigma down to the style and ending in the ovule. Some of these secretions at the stigma and the style are triggered by pollination; others appear to be a maturative stage of the pistil and are produced in a discrete way. The fact that the pollen tube depends on these secretions together with the fact that these secretions are not continuously produced confer upon the pistil a role of controlling pollen tube kinetics and point out that, for a successful fertilization, male gametophyte development and pistil maturation need to by synchronized.     

Imaging elongating pollen tubes by green fluorescent protein

Pollen tube elongation is a dynamic process in which pollen tubes navigate and respond to female tissues to accomplish their mission of delivering the sperm cells for fertilization. The tube growth process itself is driven by regulated intracellular conditions that maintain the appropriate ionic environment, actin dynamics and a balance level of exocytosis and endocytosis to support growth at the tube apex. However, the interactive process within the pistil has not rendered itself accessible for direct observation. The contribution by individual cytosolic constituents of the pollen tube growth machinery remains to be determined. With the development of the green fluorescent protein reporter system, many of these questions can be addressed in live pollen tubes that elongate within the pistil and inchemically defined media. Analyses of the mechanisms that underlie pollen tube growth will be significantly facilitated. Received: 15 March 2001 / Accepted: 30 May 2001     

High temperature limits in vivo pollen tube growth rates by altering diurnal carbohydrate balance in field-grown Gossypium hirsutum pistils

It has recently been reported that high temperature slows in vivo pollen tube growth rates in Gossypium hirsutum pistils under field conditions. Although numerous physical and biochemical pollen-pistil interactions are necessary for in vivo pollen tube growth to occur, studies investigating the influence of heat-induced changes in pistil biochemistry on in vivo pollen tube growth rates are lacking. We hypothesized that high temperature would alter diurnal pistil biochemistry and that pollen tube growth rates would be dependent upon the soluble carbohydrate content of the pistil during pollen tube growth. G. hirsutum seeds were sown on different dates to obtain flowers exposed to contrasting ambient temperatures but at the same developmental stage. Diurnal pistil measurements included carbohydrate balance, glutathione reductase (GR; EC 1.8.1.7), soluble protein, superoxide dismutase (SOD; EC 1.15.1.1), NADPH oxidase (NOX; EC 1.6.3.1), adenosine triphosphate (ATP), and water-soluble calcium. Soluble carbohydrate levels in cotton pistils were as much as 67.5% lower under high temperature conditions (34.6 °C maximum air temperature; August 4, 2009) than under cooler conditions (29.9 °C maximum air temperature; August 14, 2009). Regression analysis revealed that pollen tube growth rates were highly correlated with the soluble carbohydrate content of the pistil during pollen tube growth (r² = 0.932). Higher ambient temperature conditions on August 4 increased GR activity in the pistil only during periods not associated with in vivo pollen tube growth; pistil protein content declined earlier in the day under high temperatures; SOD and NOX were unaffected by either sample date or time of day; pistil ATP and water soluble calcium were unaffected by the warmer temperatures. We conclude that moderate heat stress significantly alters diurnal carbohydrate balance in the pistil and suggest that pollen tube growth rate through the style may be limited by soluble carbohydrate supply in the pistil.