关于野大豆盐腺问题的探讨

以中国3个省的盐生野大豆(Glycine soja Sieb. et Zucc.)为材料,在沙基培养、溶液培养和大田种植3种种植条件下用不同浓度的盐处理,观测了茎叶表面附着物的形态分布和腺毛的超微结构,测定了叶片腺毛分泌物中和叶片组织内部Na+和Cl-的含量变化,并对腺毛的3个细胞以及表皮细胞和叶肉细胞内的Na+相对含量变化进行了X射线微区分析.结果发现:盐生野大豆茎叶表皮上生长的附着物中只有表皮毛和腺毛,腺毛的形态类似于禾本科植物中的一些盐腺,叶片上的腺毛均生长在叶脉上;腺毛细胞内部结构具有一般盐腺的特点,如有大液泡,稠密的细胞质,大量的线粒体、叶绿体、胞间连丝以及较厚的细胞壁等.通过测定在无盐对照、盐处理和盐处理加盐腺泌盐抑制剂条件下盐生野大豆叶片腺毛分泌物中和叶片组织内部的Na+和Cl-含量,结果显示,盐生野大豆腺毛具有泌盐功能,加入泌盐抑制剂后,其泌盐作用停止;腺毛的3个细胞以及表皮细胞和叶肉细胞内的Na+在不同的盐浓度下的微区定位分析结果表明,盐生野大豆叶片的腺毛细胞有较强的积累Na+的能力.综合分析认为,盐生野生大豆的腺毛就是具有泌盐功能的盐腺,没有发现其他类型的盐腺.     

獐茅盐腺形态结构及其泌盐性

显微观察结果显示,獐茅盐腺为典型的双细胞结构,主要分布在叶脉附近,这样有利于它快速收集来自根部的盐离子。同时,X-ray微区分析结果表明,獐茅盐腺可以有效地将Na^＋从表皮细胞和叶肉细胞转运到基细胞,由帽细胞分泌到体外,从而降低植物体内盐分水平以适应盐渍环境。用不同盐类处理材料,獐茅对Na^＋、K^＋和Ca^2＋的吸收和分泌均表现为具有不同的选择性,分泌量的顺序为Na^＋〉K^＋〉Ca^2＋,并且仅仅24h内,盐分的分泌量就已经超过了叶片内的含量,结果植株体内的总离子含量水平几乎不变,说明獐茅具有较强的泌盐能力。     

栽培大豆和野生大豆耐盐性及离子效应的比较

以国际上常用的耐盐大豆（Glycine max L.)品种Lee68为对照,在发芽期和苗期两个阶段,利用发芽指数、指害指数和耐盐系数等指标对一年生具盐腺野生大豆（Glycine soja L.)和部分栽培大豆（Glycine max L.)及某些野生大豆品系或品种的耐盐性进行了比较,讨论了耐盐指标的可行性。从离子效应方面比较了Na^ 和Cl^-对大豆发芽率的影响,并对具盐腺野生大豆的耐盐机理进行了初步分析。结果表明,大豆品种的耐盐性在发芽期和苗期无一致相关性。轻度等渗胁迫下,Na^ 对种子发芽率的抑制作用大于Cl^-,而重度等渗胁迫下则相反。通过减少由根系吸收的Na^ 、Cl^-向叶片的运输,维持叶片中较高含量的K^ ,减轻盐离子毒害,可能是具盐腺野生大事耐盐的主要生理机制之一。     

烟台补血草盐腺结构及发育过程观察

利用叶表皮离析、扫描电镜以及常规石蜡切片法对烟台补血草[ Limonium franchetii( Debx.) Kuntze]叶片盐腺的分布和结构特征及其发育过程进行了观察.结果表明:烟台补血草叶片上、下表皮均有盐腺分布,上、下表皮的盐腺密度分别为7.57和8.09 mm-2,同一时期叶片上表皮盐腺密度略小于下表皮.烟台补血草的成熟盐腺是由20个细胞构成的复合结构,其中,中央有4个分泌细胞,每个分泌细胞外侧均伴有1个长方形的毗邻细胞,再向外依次包围着4个内杯状细胞和4个外杯状细胞,靠近叶肉细胞处还有4个收集细胞,收集细胞与盐腺的其他细胞同源;在4个分泌细胞顶端的角质层中央各有1个小孔,称为泌盐孔.烟台补血草盐腺发育过程依次经历原表皮细胞期、2细胞期、4细胞期、8细胞期、16细胞期和20细胞期6个阶段,由1个单独的原表皮细胞发育而成,发育过程中细胞均进行垂周分裂;另外,同一时期的叶片存在盐腺发育不同步的现象.根据观察结果推测烟台补血草主要通过泌盐孔L向外泌盐.     

盐胁迫下盐地碱蓬体内无机离子含量分布特点的研究

用不同浓度NaCl溶液处理盐地碱蓬（Suaeda salsa)植株后,测定并比较老叶、幼叶及根部的无机离子含量和对K的选择性,叶片及根部的Na^ 、Cl^-含量随盐度的增加而升高,且累积趋势相似,盐胁迫下根部Na^ 、Cl^-及总离子含量（K^ 、Na^ 、Ca^2 ,NO3^-,Cl^-)明显低于叶片,说明盐地碱蓬地盐胁迫下,以叶片优先积累大量离子（如Na^ ,Cl^-) 为其适应特征。NaCl处理下,叶片的K^ ,Ca^2 含量低于对照,但随盐度的增加保持相对稳定,而根部K^ 含量,K/Na比、对K的选择性则高于叶片,这对盐胁迫下地上部的K^ 亏缺有一定补偿作用。低盐度处理（100mmol/LNaCl)促进NO3^-的吸收,另外随盐度的增加,叶片渗透势下降,渗透调节能力增强,幼叶渗透势低于老叶,但渗透调节能力相同。     

不同生态环境野生大豆的结构比较研究

对生长在不同生态环境的蝶形花科Ｆａｂａｃｅａｅ 大豆属Ｇｌｙｃｉｎｅ 的两个野生大豆Ｇ．ｓｏｊａ 品系进行了扫描电镜观察及比较研究．结果表明,生长在盐渍生态环境的野生大豆茎和叶体表都具有盐腺,盐腺圆球型,基部有一个小柄,着生在盐生野生大豆茎、叶表皮外切向壁的胞间层处．幼嫩的盐腺靠泌盐孔泌盐,成熟的盐腺靠整体破碎释盐．而生长在黑土地生态环境的野生大豆的茎和叶外切向壁未发现有泌盐的盐腺,其茎叶的表皮都呈现出平滑状态．因此两种不同生态环境的同科同属植物在微观结构上显示出明显差异．     

运城盐湖4种藜科盐生植物叶的比较解剖研究

应用扫描电镜和光学显微镜对山西运城盐湖周围盐渍环境中4种藜科（Chenopodiaceae）盐生植物叶的结构进行了比较解剖研究。结果表明,碱蓬（Suaeda glauca Bunge）和盐地碱蓬（Suaedasalsa（Linn．）Pall．）属真盐生植物,结构特征相似：叶线形、肉质化,表皮上气孔器密集,叶肉具有发达的储水组织细胞和栅栏组织。灰绿藜（Chenopodium glaucum Linn．）和西伯利亚滨藜（Atriplex sibirica Linn．）为泌盐盐生植物,其中,灰绿藜具有双细胞构成的盐腺,西伯利亚滨藜则具有盐囊泡,此外,两种泌盐盐生植物中存在的异细胞和含晶细胞,对适应盐生环境有积极意义。从表皮细胞来看,4种植物的叶都有相同的适盐特征。总之,4种藜科盐生植物的叶片结构具有适盐的共同性和个体的多样性特征。     

运城盐湖4种藜科盐生植物叶的比较解剖研究

应用扫描电镜和光学显微镜对山西运城盐湖周围盐渍环境中4种藜科(Chenopodiaceae)盐生植物叶的结构进行了比较解剖研究.结果表明,碱蓬(Suaeda glauca Bunge)和盐地碱蓬(Suaeda salsa (Linn.) Pall.)属真盐生植物,结构特征相似:叶线形、肉质化,表皮上气孔器密集,叶肉具有发达的储水组织细胞和栅栏组织.灰绿藜(Chenopodium glaucum Linn.)和西伯利亚滨藜(Atriplex sibirica Linn.)为泌盐盐生植物,其中,灰绿藜具有双细胞构成的盐腺,西伯利亚滨藜则具有盐囊泡,此外,两种泌盐盐生植物中存在的异细胞和含晶细胞,对适应盐生环境有积极意义.从表皮细胞来看,4种植物的叶都有相同的适盐特征.总之,4种藜科盐生植物的叶片结构具有适盐的共同性和个体的多样性特征.     

红树植物白骨壤叶片的解剖结构及其生态适应性

运用石蜡切片的方法对红树植物白骨壤的叶片进行解剖学的观察和研究。结果表明:白骨壤的叶为异面叶;上表皮为复表皮,有厚的角质膜及下皮层;下表皮上有大量的泌盐腺毛;栅栏组织多层,约占叶肉组织的2/3,海绵组织退化;机械组织和输导组织均很发达。反映了白骨壤叶片的结构与其生活的海生环境高度相适应。     

碱蒿营养器官的扫描电镜观察研究

用扫描电子显微镜对碱蒿（Artemisia anethifolia）营养器官的解剖学特征进行了观察与研究。结果表明：碱蒿属于典型的泌盐盐生植物。叶肉质化,表皮上气孔为无规则型气孔,密集下陷,有较多的盐囊泡和分杈腺毛分布,表皮细胞外壁加厚,外壁的外层角质化,为等面叶,栅栏组织细胞排列疏松,叶中央为发达的储水组织,木质部有多束维管束;茎表皮上有少许气孔,并分布有腺毛和众多盐囊泡,表皮细胞外壁加厚形成角质层,皮层宽度较小,皮层薄壁组织细胞内可见淀粉粒,中柱后生木质部为口径大的导管,原生木质部为口径小的导管,管内充满盐晶体,中间有发达的贮水薄壁细胞;根的表皮细胞排列疏松,外皮层细胞排列紧密而整齐,中部皮层薄壁细胞层数较多,细胞中贮藏有许多淀粉粒,内皮层细胞排列紧密,初生木质部导管发达,内部周围存在大量盐晶体,根的次生木质部有通气组织。这些解剖结构均表现出碱蒿具有适应盐碱、干旱生境的结构特征。     

NaCl胁迫下野生和栽培大豆幼苗体内离子的再转运

采用NaCl根际处理和叶面饲喂^22Na方法,研究了野生大豆(Glycine soja)——耐盐的BB52、盐敏感的N23232和栽培大豆(Glycine max)——较耐盐的Lee68幼苗在盐胁迫及解除过程中对Na^ 、Cl^-的吸收和再转运。结果表明,在NaCl根际处理12h过程中,BB52和Lee68幼苗根对Na^ 、Cl^-吸收和向茎、叶的运输逐渐增加,10h时趋于稳定,Na^ 、Cl^-含量高低顺序是根＞茎＞叶。但N23232的Na^ 、Cl^-含量则是茎＞根＞叶。在用NaCl对根处理10h后再解除NaCl处理的0～36h内,BB52吸收的Na^ 、Cl^-较多地留于根部或转运至根茎过渡区,叶中较少。N23232吸收的Na^ 较多地转运至茎部,而Cl^-含量在幼苗各部分无差异。叶片饲喂^22Na 10h后,BB52吸收^22Na较N23232多,并较多地向根部运输。从离子再转运角度讨论了BB52的耐盐性。     

江苏野生大豆的耐盐性和离子在体内的分布及选择性运输

以相对发芽率和出苗率为指标比较了3个野生大豆(Glycine soja)种群的耐盐性,测定了NaCl胁迫下2个耐盐性不同的野生大豆种群(江苏野生大豆,JWS,耐盐;N23232,盐敏感)植株根、茎和叶片中Na^+、K^+和Cl^-含量的变化。结果表明,JWS的耐盐性最强,盐胁迫抑制野生大豆幼苗生长,使其干物质积累量减少,根冠比上升,对耐盐性弱的N23232抑制作用大于耐盐性强的JWS,不同器官离子含量测定结果表明,盐胁迫下野生大豆茎部Na^+含量最高,耐盐的JWS根系具有积累Na^+和Cl^-的能力,叶片Na^+、Cl含量较低,而盐敏感种群N23232根系中：Na^+、Cl^-含量低于耐盐种群JWS,叶片中Na^+、Cl^-含量则高于JWS,JWS根系对K^+、Na^+吸收的选择性(selectivity ratio,SK,Na)和N23232没有明显差异;但叶片和茎运输的SK,Na明显高于N23232,使地上部K^+／Na^+较高,因此认为野生大豆根系对Na^+、Cl^-的积累及K^+向地上部运输的选择性高是其耐盐性强的主要原因。     

Differential sensitivity to chloride and sodium ions in seedlings of Glycine max and G. soja under NaCl stress

High Na+ and Cl- concentrations in soil cause hyperionic and hyperosmotic stress effects, the consequence of which can be plant demise. Ion-specific stress effects of Na+ and Cl- on seedlings of cultivated (Glycine max (L.) Merr) and wild soybean (Glycine soja Sieb. Et Zucc.) were evaluated and compared in isoosmotic solutions of Cl-, Na+ and NaCl. Results showed that under NaCl stress, Cl- was more toxic than Na+ to seedlings of G. max. Injury of six G. max cultivars, including 'Jackson' (salt sensitive) and 'Lee 68' (salt tolerant), was positively correlated with the content of Cl- in the leaves, and negatively with that in the roots. In subsequent research, seedlings of two G. max cultivars (salt-tolerant Nannong 1138-2, and salt-sensitive Zhongzihuangdou-yi) and two G. soja populations (BB52 and N23232) were subjected to isoosmotic solutions of 150mM Na+, Cl- and NaCl, respectively. G. max cv. Nannong 1138-2 and Zhongzihuangdou-yi were damaged much more heavily in the solution of Cl- than in that of Na+. Their Leaves were found to be more sensitive to Cl- than to Na+, and salt tolerance of these two G. max cultivars was mainly due to successful withholding of Cl- in the roots and stems to decrease its content in the leaves. The reverse response to isoosmotic stress of 150 mM Na+ and Cl- was shown in G. soja populations of BB52 and N23232; their leaves were not as susceptible to toxicity of Cl- as that of Na+. Salt tolerance of BB52 and N23232 was mainly due to successful withholding of Na+ in the roots and stems to decrease its content in the leaves. These results indicate that G. soja have advantages over G. max in those traits associated with the mechanism of Cl-tolerance, such as its withholding in roots and vacuoles of leaves. It is possible to use G. soja to improve the salt tolerance of G. max.     

Effects of salinity and benzyl adenine on development and function of microhairs of Zea mays L

Bicellular microhairs are present on the surfaces of leaves of grasses with the exception of the Pooideae. In some halophytic grasses, these glandular hairs secrete salt, suggesting the intriguing question ‘can the microhairs of grasses that do not normally encounter salinity also secrete salt?’ Microhairs were counted in replicas of the adaxial and abaxial surfaces of leaves of various ages of maize plants growing either in the absence of salt or in the presence of 40, 80 or 120 mM NaCl. The number of microhairs per unit area of adaxial leaf surface of the youngest leaf almost doubled as the salinity increased from zero to 120 mM NaCl; on the abaxial surface, the number of microhairs increased by 50%. Spraying this leaf with benzyl adenine (BA) caused, when averaged across salinities and surfaces, a 32% increase in the number of microhairs. Salinity reduced leaf area but in all the salinity treatments, spraying with BA increased the total number of microhairs per leaf. Washing leaves of plants provided estimates of the loss of salt from those leaves. There were large differences between the Na:K molar ratios in the washing solution and the leaf tissue, indicating a high selectivity for sodium over potassium for loss from the leaf. BA did not influence the efficiency of salt loss, expressed per microhair, at any salinity level, but did increase loss per leaf. Thus, BA increased salt loss from plants due to its influence on the number of microhairs and leaf area, but not due to its effect on the efficiency of the secretion process per se.     

Development and Structure of Internal Glands and External Glandular Trichomes in Pogostemon cablin

Pogostemon cablin possesses two morphologically and ontogenetically different types of glandular trichomes, one type of bristle hair on the surfaces of leaves and stems and one type of internal gland inside the leaves and stems. The internal gland originates from elementary meristem and is associated with the biosynthesis of oils present inside the leaves and stems. However, there is little information on mechanism for the oil biosynthesis and secretion inside the leaves and stems. In this study, we identified three kinds of glandular trichome types and two kinds of internal gland in the Pogostemon cablin. The oil secretions from internal glands of stems and leaves contained lipids, flavones and terpenes. Our results indicated that endoplasmic reticulum and plastids and vacuoles are likely involved in the biosynthesis of oils in the internal glands and the synthesized oils are transported from endoplasmic reticulum to the cell wall via connecting endoplasmic reticulum membranes to the plasma membrane. And the comparative analysis of the development, distribution, histochemistry and ultrastructures of the internal and external glands in Pogostemon cablin leads us to propose that the internal gland may be a novel secretory structure which is different from external glands.     

Effects of salinity on seed set in rice

Salinity reduces fertility in rice (Oryza sativa L.), but little is known of the underlying cause(s). In order to determine the relative importance of pollen viability and stigmatic receptivity for seed setting, plants of the rice cultivar IR36 were treated with ‘artificial’ sea water (0,10, 25 or 5Omol^?3 with respect to NaCl) from 1 month after germination until the main tiller flowered. An increase in the salinity in the medium resulted in a decrease in the number of fertile florets and in the viability of pollen as determined both by pollen germination and by pollen staining with the tetrazolium salt 3-(4,5-dimethyl-ithyazolyl)-2,5-diphenyl monotetrazolium bromide. In order to assess the effects of salt on stigmas, seed production was measured for salt-grown and non-salt-grown female plants pollinated with viable pollen (from plants grown in the absence of salt). The percentage of seed set was reduced by 38% when the female plants were grown in 1Omol m^?3 Na and by 72% at 25mol m^?3 Na: no seed setting was recorded for plants grown in 50mol m^?3 Na. Comparisons between crosses involving male and female parents grown at different salinities indicated that effects on the female plants dominated those on pollinator plants. Mineral analysis of leaves of different ages showed that there was a gradient of K concentration from leaf to leaf which was opposite to that of Na and Cl at all levels of applied salinity: K was maximal in the flag leaf, where Na and Cl were minimal. Analysis also revealed that there was an increase in the concentrations of Na and Cl and a decrease in the concentration of K in the pollen grains and stigmas of plants subjected to saline conditions. Correlations between the concentration of Na and Cl in pollen and pollen staining and pollen germination in vitro suggest that Na and Cl perse were responsible for the poor viability. The change in ionic concentrations in pollen and stigmas was much larger than that in the younger leaves, and in particular very much larger than that in the lemmas and paleas.     

X-Ray Micro-Analysis of Cells and Cell Compartments of A triplex spongiosa: I. LEAVES

Atriplex spongiosa was grown in hydroponic culture with additionsof 0, 200, 400 and 600 mM NaCl. Frozen, hydrated cells and cellcompartments of young and mature leaf tissue were analysed byX-ray micro-analysis. Evidence for low K + Na and Cl content,and high K selectivity in the bundle sheath cytoplasm was obtainedfrom data on X-ray count ratios and on total X-ray counts. Vacuolesof the major cell types of the mature leaf had either high Kor high Na and Cl contents when grown in the absence or presenceof NaCl. Comparison of K, Na and Cl content of different cell types inthe mature leaf showed gradients in selectivity for K. relativeto Na between the bundle sheath cells and the bladder cells.In the young expanding leaves salt was sequestered in the numeroussalt bladders on the leaf surface, while the cytoplasm and developingvacuoles of undifferentiated cells contained largely K and littleNa or Cl. The results support general views on the compartmentation ofsalt in plants cells in relation to osmotic or saline stress. Key words: Atriplex spongiosa, X-ray analysis, Salinity, Compartmentation, Leaf