Effects of the Direction of Gravistimulation on Tuber Formation and Amyloplast Distribution in Tuber Tips of Chinese Yam

Abstract

The effects of gravistimulation direction on tuber formation and amyloplast distribution in the tuber tips of Chinese yam were investigated. Tubers placed vertically for either 2 or 14 d elongated in the direction of gravity vector. The subapical parts of tubers that were positioned horizontally for 2 d curved slightly toward the gravity direction, and such tubers elongated downward after 14 d. In tubers that were inversed for 14 d, the tips bent and eventually elongated in the direction of the gravity vector. These results indicated that the subapical part of the tuber was the initial site of curvature in response to gravistimulation. Microscopy and measurement of amyloplast sedimentation ratios showed that many amyloplasts sedimented downward in each tip cell of tubers that were placed vertically, inversely or horizontally. The results indicated that amyloplast sedimentation direction corresponded with the eventual direction of tuber elongation under different gravistimulation orientations. Tubers rotated at 90° intervals every day for 14 d did not have an elongating shape and grew multiple tips at different angles. In the rotated tubers, amyloplasts dispersed within the tip cells. These results showed that proper sedimentation of amyloplasts would be essential for the normal elongation and formation of tubers. The results of this study supported the possibility that sedimentable amyloplasts in the tuber tip were involved in gravity sensing and tuber formation.     

Morphological Studies on the Mobilization of Reserves in Japanese Yam (Dioscorea japonica Thunb.) Seed Tuber and Eddo (Colocasia esculenta Schott var. antiquorum Hubbard & Rehder) Seed Corm on and after Sprouting

Abstract

We examined the mechanism of reserve mobilization in Japanese yam seed tubers and eddo seed corms on and after sprouting. The decomposition of starch in pith parenchyma cells of Japanese yam tubers and eddo corms progressed from the region distant from vascular bundles to that adjacent to vascular bundles. In eddo corms, the starch also decomposed from the proximal to the distal region adjacent to the sprout or regenerate plant body. In the yam tubers, the decomposition process was similar in the proximal, middle and distal regions. The first step in the reserve mobilization in pith parenchyma cells was the decomposition of the amyloplast envelope. Subsequently, starch granules decomposed. In Japanese yam tubers, the envelope and starch granules started to decompose from the peripheral regions of the amyloplasts. The observation of soluble polysaccharides, which was the decomposition product of starch granules, was made possible by the quick freezing-vacuum freeze-drying method. By this method, we demonstrated that the soluble polysaccharides in the parenchyma cells decomposed and decreased in density. In addition, the mucilage in the mucilage duct started to decompose and decreased in density from the proximal to the distal part of the corm and also from the periphery to the center of the duct. It was shown that not only starch mobilization but also mucilage mobilization mainly supported sprouting and the growth of the regenerate plant body during about the first half of the vegetative stage.     

山药块茎代谢物质含量及其相关性分析

采用多变量统计方法,比较3份山药材料(桂淮2号、桂淮5号、G16)采收期块茎中14个代谢产物含量及其相关性。结果表明,G16的水分、可溶性总糖、蔗糖、苹果酸、酒石酸、皂苷及可滴定酸的含量显著高于桂淮2号、5号,还原糖、可溶性蛋白质含量显著低于桂淮2号、5号。苹果酸、酒石酸、可滴定酸等酸类物质之间呈显著相关,其它物质之间相关性在品种间有差异。3个品种中14个代谢产物可由4个公因子分别反映98.15%、93.11%、94.03%的信息量,酸类物质是各品种第1公因子,其余公因子在品种间不一致。表明不同品种山药代谢产物的含量、相关性、关键因子有差异,从而形成不同品质效应,酸类物质在山药块茎物质代谢和品质形成中起关键作用。     

淮山中多酚氧化酶特性及无硫护色脱水工艺

酶促褐变是导致淮山脱水加工过程中色泽变化的主要原因。通过研究淮山中多酚氧化酶的最适pH 值、最适温度等主要特性,设计选取适当的非硫成分NaC1、VC、柠檬酸进行护色,通过正交实验得到一种安全有效的无硫复合护色液,即含质量分数0.7%NaC1、0.3%Vc、0.6%柠檬酸的水溶液。在脱水加工过程中,用该护色液对淮山片浸泡护色4h后,在65℃下干燥4.5h,得到与传统硫熏漂白同样好色泽的终产品。     

Endogenous Gibberellins in Bulbils of Chinese Yam during Growth and Storage

Abstract

Five gibberellins in the early-13-hydroxylation pathway (GA₅₃, GA₄₄, GA₁₉, GA₂₀ and GA₁), and six gibberellins in the non-13-hydroxylation pathway (GA₁₂, GA₁₅, GA₂₄, GA₉, GA₃₆ and GA₄), were detected in the bulbils of Chinese yam. This indicated the presence of two gibberellin biosynthetic pathways in bulbils. The total endogenous gibberellins were dramatically increased in enlarged bulbils. The endogenous level of bioactive GA₄ was always higher than that of GA₁. A rapid increase in endogenous gibberellins including bioactive GA₄ was observed during a 30-day storage period. These results show that gibberellins are closely related to bulbil enlargement and dormancy in Chinese yam plants. However, further research is needed for better understanding of the fluctuation of gibberellin levels in bulbils of Chinese yam during storage.     

福建山药地方资源主要农艺性状与品质特性比较

为了筛选出福建山药优良种质资源,为选育高产、优质的山药品种奠定基础,对收集自福建的24份山药农家品种的主要农艺性状与品质特性进行分析。结果表明,永定薯、MYSY1长势较旺,有不规则、较大零余子,且产量最高。漳州直薯、漳州块薯和松溪薯长势旺,无零余子;漳州直薯和块薯产量较高,但口感一般;松溪薯产量较高,但肉质疏松、含水量高、易氧化,口感较差,烘干后黑褐色。明溪薯、MSSY资源和清流薯长势中,无零余子,采收期长,含水量较少,肉质紧密,断面白而粘液多,口感好,烘干后颜色较白;永安薯长势中,无零余子,含水量少,淀粉和冷浸出物含量较高,烘干后色泽好,但其肉质结实,口感欠佳,且茎块小产量低;JYSY2、JYSY10和JYSY12资源长势弱,有少量零余子。安溪薯、松溪薯及漳州块薯的块茎形状为块状,其它资源的为长圆柱形、圆柱形。经聚类分析将24个品种分成了3组。综合评价,MSSY资源、MYSY1资源、明溪薯和清流薯具有较好农艺性状和品质特性,开发潜力巨大。     

小麦内胚乳细胞及其淀粉体的发育

为了探明小麦内胚乳细胞发育和淀粉体生长的规律,以不同发育天数的小麦颖果为材料,利用树脂半薄切片和胚乳细胞分离等方法研究了内胚乳细胞及其淀粉体的形态、数目和生长过程.结果如下:(1)小麦内胚乳细胞呈不规则的多面体形态,内含大、小两种淀粉体,大淀粉体呈鹅卵石形,小淀粉体呈圆球形;(2)内胚乳细胞的生长呈“S”型曲线,花后16～24 d是细胞生长最快的时期;(3)大淀粉体的增殖和生长主要在花后4～16 d进行,小淀粉体在花后16 d大量出现并快速增殖,至胚乳发育后期小淀粉体数量占内胚乳细胞淀粉体总量的90％以上;(4)内胚乳细胞核在颖果发育中、后期发生衰亡,淀粉体在核衰亡过程中仍然能增殖和生长.     

全周期间作模式胶园内间作豆薯的产量及其抗逆生理的特征

研究全周期间作模式胶园大行间间作的豆薯产量及其抗逆性。结果表明,试验期间间作豆薯小区的橡胶株产与常规种植胶园的没有显著差异;间作豆薯的产量为12.7 t/hm2,与单作豆薯的产量(13.5 t/hm2)没有显著性差异,但不同位置间作的豆薯产量间存在差异,以大行中间至少6 m宽的产量最高,显著高于靠近橡胶树两边的豆薯产量(p<0.05);不同位置间作豆薯叶片的游离脯氨酸(Pro)含量、丙二醛(MDA)含量、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性与单作对照总体上无显著性变化(除E4和M的SOD活性以及E1的Pro含量显著低于单作外)(p<0.05)。表明在全周期间作模式胶园大行间间作豆薯是可行的。     

春小麦淀粉粒的分布及其与品质的相关性

为了研究小麦淀粉粒的大小及分布对小麦品质状况的影响,对不同筋力类型的8份春小麦品种进行了A、B型淀粉颗粒的电镜分析,并测定这些品种的直/支淀粉含量、膨胀势及面粉吸水率等品质指标。结果表明,强筋型小麦直径小于16 μm的淀粉粒占A型淀粉粒总数的比例最大,而中筋和弱筋型小麦直径大于20 μm的淀粉粒占A型淀粉粒总数的比例最大,与其他筋力型差异显著;B型淀粉粒直径大小在不同筋力型品种间差异不显著,其形状在弱筋品种武春121中呈现不规则形。相关分析表明,A型淀粉粒的平均直径与支链淀粉含量、膨胀势和吸水率呈显著正相关,而B型淀粉粒的平均直径与上述品质参数相关不显著,说明A型淀粉粒的大小对上述小麦品质指标具有一定的影响,而B型淀粉粒的影响较小。     

Bitterness and Toxicity in Wild Yam (<Emphasis Type="Italic">Dioscorea</Emphasis> spp.) Tubers of Nepal

Wild yams make a significant contribution to diets of tribal people in Nepal. However, these wild tubers are unpalatable, taste bitter, produce inflammation and show occasional toxicity. Four wild yam species, which are eaten after primary treatment by Nepali aborigines, were analyzed for bitter and toxic principles. Bitter components were identified as furanoid norditerpenes (diosbulbins A and B). Diosbulbins A and B were found in the range of 0.023–0.046 and 0.151–0.442 g kg⁻¹, respectively. Results demonstrated that diosbulbin B, with an average value of 0.314 g kg⁻¹, was the principal bitter compound as compared to diosbulbin A (0.037 g kg⁻¹). The toxic alkaloid, dioscorine and histamine (an allergen) were not detected in these tubers, whereas cyanogens (as HCN equivalent) content were found ranging from 3.2 to 6.0 ppm. Our results revealed that Nepali wild yam tubers are not toxic varieties, as they do not contain either toxic dioscorine or histamine and cyanogens contents were satisfactorily below the safety limits. The inflammation and occasional toxicity observed could possibly be due to the presence of high level of oxalate in these tubers. Domestic cooking methods were found to be very efficient in removing bitterness, thus making the bitter yams palatable.     

小麦淀粉粒蛋白表达差异及其与淀粉糊化特性的关系

为探明小麦淀粉粒蛋白与淀粉糊化特性的关系,对河南省18个主栽小麦品种淀粉粒蛋白进行分离,并对淀粉粒蛋白类型、淀粉含量、糊化特性参数进行了研究.结果表明,18个小麦品种分离出了8种主要的淀粉粒蛋白,9种组合带谱,并以组合类型Ⅰ和组合类型Ⅶ所占比例最高,为55.56%,均表现为7条谱带.通过对淀粉粒蛋白条带数量以及谱带光密度总量和淀粉特性的相关性分析表明,淀粉粒蛋白光密度总量和直链淀粉含量、峰值黏度、低谷黏度、最终黏度呈显著负相关,表明淀粉粒蛋白表达量影响淀粉的糊化特性.同时选取6个小麦品种,分别采用盐、SDS、蛋白酶对淀粉进行处理后,淀粉峰值黏度显著提高,其中以盐处理提高幅度最大,且不同处理之间差异达显著水平.对处理后淀粉粒蛋白进行电泳分析表明,处理后的条带明显减少,说明处理后小麦淀粉粒蛋白含量下降.综合试验结果,不同小麦品种淀粉粒蛋白表达存在差异,同时淀粉粒蛋白表达量高低影响淀粉峰值黏度.     

小麦籽粒淀粉粒粒级分布特征及其与淀粉理化特性关系研究进展

小麦籽粒淀粉粒粒级分布范围大,而且呈现梯度分布,这是小麦淀粉粒区别于其他植物淀粉粒的一个显著特征。不同粒径的淀粉粒在理化特性上有极大的差异,因此除直/支链淀粉比例之外,淀粉粒粒级分布也是影响淀粉品质的重要指标。本文综述了国内外在小麦籽粒淀粉粒粒级分布及其与淀粉品质特性关系方面的研究进展,提出应注意小麦籽粒不同粒级淀粉粒分布特征及其形成机理与调控途径等领域的研究,以促进优质小麦品种选育和调优栽培技术的建立。     

乙氧氟草醚在水稻及其生态环境中的残留降解动态

乙氧氟草醚在水稻及其生态环境中的残留降解动态楼小华，梁天锡，吴园生，平霄飞（中国水稻研究所杭州３１０００６）关键词乙氧氟草醚，残留降解，最终残留ＤｅｇｒａｄａｔｉｏｎＤｙｎａｍｉｃｓｏｆＯｘｙｆｌｕｏｒｆｅｎｉｎＲｉｃｅａｎｄＩｔｓＥｃｏｓｙｓｔｅｍ...     

小麦籽粒淀粉理化特性与品质关系及其生理机制研究进展

淀粉作为籽粒主要组分,是小麦加工品质最重要的决定因素之一。淀粉的加工品质主要取决于直链与支链淀粉含量及其比值、淀粉分子精细结构和淀粉颗粒大小分布等理化特性。明确小麦籽粒不同部位淀粉理化特性、空间分布差异及其形成的调控机制,可深入阐释面粉品质性状差异形成的生理机制。本文从小麦籽粒淀粉理化特性空间分布、淀粉合成关键酶活性及其编码基因时空表达模式等角度综述了小麦籽粒淀粉理化特性空间分布特征形成的生理机制,以期为小麦品质形成机制与调优栽培技术的建立提供理论支持。     

不同小麦品种抗性淀粉含量及其与其他淀粉品质性状的关系

为了解不同小麦品种抗性淀粉含量的差异及其与其他淀粉品质性状的关系,以30个小麦品种为试验材料,分别在河南省7个地点种植,对面粉中抗性淀粉含量、淀粉组分、淀粉糊化特性、淀粉粒度分布等进行了分析。结果表明,所有被测品质性状均受环境、基因型影响,且多数指标的环境效应大于基因型效应。7个地点间比较,抗性淀粉含量及淀粉品质性状的综合表现在开封点和原阳点均优于其他地区。供试小麦品种的抗性淀粉含量为1.47%～2.28%,平均为1.88%,以赛德麦1号、百农4199、许科316等品种的抗性淀粉含量较高。经相关分析,抗性淀粉含量与直链淀粉含量、峰值粘度、低谷粘度、最后粘度呈显著正相关。以上结果说明,提高小麦抗性淀粉含量,一定程度上可以改善淀粉的糊化特性。     

Localization and Characterization of Ferritin in Demospongiae: A Possible Role on Spiculogenesis

Iron, as inorganic ion or as oxide, is widely used by biological systems in a myriad of biological functions (e.g., enzymatic, gene activation and/or regulation). In particular, marine organisms containing silica structures—diatoms and sponges—grow preferentially in the presence of iron. Using primary sponge cell culture from S. domuncula–primmorphs—as an in vitro model to study the Demospongiae spiculogenesis, we found the presence of agglomerates 50 nm in diameter exclusively inside sponge specialized cells called sclerocytes. A clear phase/material separation is observed between the agglomerates and the initial stages of intracellular spicule formation. STEM-HRTEM-EDX analysis of the agglomerates (30–100 nm) showed that they are composed of pseudohexagonal nanoparticles between 5 and 15 nm in size, displaying lattice parameters corresponding to hematite (Fe₂O₃) and mixed iron oxide phases typically attributed to ferritin. Further analysis, using western blotting, inductively coupled plasma mass spectrometry (ICP-MS), sequence alignment analysis, immunostaining and magnetic resonance imaging (MRI), of mature spicule filaments confirm the presence of ferritin within these organic structures. We suggest that S. domuncula can be classified as a dual biomineralizating organism, i.e., within the same cellular structure two distinct biomineralizing processes can occur as a result of the same cellular/metabolic function, spiculogenesis.     

冬小麦叶茎粒可溶性糖含量变化及其与籽粒淀粉积累的关系

在池栽条件下研究了鲁麦22和鲁麦14两个冬小麦品种旗中、倒二茎、籽粒糖含量及籽粒淀粉积累速率的变化。结果表明，小麦叶片可溶性糖和蔗糖含量在开花后15－20d出现高峰；茎可溶性总糖、蔗糖和果聚糖含量变化呈单峰曲线，最高含量亦出现在花后15－20d，而籽粒可溶性总糖和蔗糖含量在灌浆期呈下降趋势，花后20d至成熟期各器官糖含量与籽粒淀粉积累密切相关。     

噻嗪酮在水稻上的内吸输导作用和消解动态

 通过液相色谱检测结合生物活性测定与田间试验，证明水稻对噻嗪酮具有明显的内吸辅导作用。 稻茎可吸收和富集田水中的噻嗪酮，浓缩系数为2.4～3.5.施药187.5 g(ai)／ha后1～4周，噻嗪酮在稻茎中的消失率依次为73．30％、90.32％和95.01％。粗喷雾、泼浇、弥雾、毒土（有水层）等不同施药方式之间的防效差异不显著。试验表明，噻嗪酮对稻飞虱的高度生物活性，在水稻上的内吸作用和稻茎对田水中药剂的吸收、富集能力，是该药在田间表现长效的主要原因。     

哈尔滨地区大豆蚜及其天敌昆虫的多年种群动态和相关性分析

为明确大豆蚜种群数量与其天敌昆虫龟纹瓢虫[Propylea japonica(Thunberg)]、异色瓢虫[Harmonia axyridia(Pallas)]及花蝽(Orius sp.)的田间发生情况及二者的相关性,采用对角线五点取样、借助直接观察法,对哈尔滨地区大豆蚜及上述天敌昆虫的种群动态(2008-2014年)进行了系统调查。记录各年份大豆蚜种群数量峰值及峰值日后第6天各天敌昆虫的种群数量,并对大豆蚜与天敌昆虫的发生关系进行了相关分析。结果表明:6月为大豆蚜的田间始发期,7-8月为其田间猖獗期,9月为其消亡期。在大豆蚜的始发期和猖獗期,田间均有龟纹瓢虫(成虫和幼虫)、异色瓢虫(成虫和幼虫)及花蝽(成虫和若虫)的发生。龟纹瓢虫幼虫和异色瓢虫成虫的田间种群数量与大豆蚜的种群数量间均呈现显著相关性。     

Effects of elevated CO2 concentration on bulbil germination and early seedling growth in Chinese yam under different air temperatures

The present study investigated the effects of elevated carbon dioxide concentration ([CO₂]) and air temperature on the germination of seed bulbils and the seedling vigour of two Chinese yam lines. Plants were grown under two [CO₂] levels, ambient and elevated (ambient + 200 μmol mol^?1), and two mean air temperature regimes, 22.2 °C (ambient + 1.4 °C) and 25.6 °C (ambient + 5.2 °C). Elevated [CO₂] did not affect bulbil germination under both air temperature regimes. During the early growth stage, the dry weight (DW) of leaves, vines, shoots, roots, belowground parts (roots + tubers) and whole plants were higher under elevated [CO₂] than ambient [CO₂] for both lines under the low- and high-temperature regimes. The values of vigour indexes (index I = germination % × seedling length and index II = germination % × seedling DW) were also higher under elevated [CO₂] than ambient [CO₂] for both lines. These results indicated that Chinese yam seedlings respond positively to elevated [CO₂] during the early growth stage. The above:belowground DW ratios were lower under elevated [CO₂] than ambient [CO₂] in seedlings with very small new tubers for both yam lines, indicating that elevated [CO₂] strongly affected the root growth in the early growth stage. The DWs of post-treatment seed bulbils were higher in the elevated [CO₂] under both air temperature regimes. The results showed that Chinese yam used a smaller amount of the reserves in seed bulbils under elevated [CO₂] than under ambient [CO₂].