低锌和缺锌对玉米生长发育的影响

以玉米沈单10号为材料,用溶液培养的方法研究了缺锌、低锌和正常供锌对玉米生长发育的影响,进一步明确了一定量低锌比缺锌对玉米的伤害更大,并对其POD、SOD、CAT同工酶谱及蛋白质表达进行了分析、结果表明：一定浓度的低锌培养使玉米生长受抑及受害最重,且地上部分比地下部分更敏感。低锌和缺锌处理时3种同工酶的酶谱和蛋白表达与正常供锌时均有明显的差异,尤其在一定量低锌浓度时,有些同工酶的表达增强或被特异性诱导,而另一些酶的合成受阻;低锌和缺锌处理都诱导出了新的蛋白组分,也缺失了部分蛋白组分,且低锌比缺锌时缺失的蛋白组分更多。这些变化可能与玉米生长发育及受害密切相关。     

玉米花药发育的细胞生物学与分子遗传学的研究方法

雄性不育技术在玉米杂种优势利用和杂交种生产中发挥着重要作用,玉米花药发育和雄性不育的细胞生物学与分子遗传学研究是雄性不育技术利用的前提和基础。玉米花药发育是一个复杂的生物学过程,需要孢子体基因与配子体基因的协同表达调控。从玉米花药的形态结构、花药发育时期的划分、花药败育类型、花药发育的细胞学研究方法、花药发育的组学研究方法、花药发育分子遗传学研究方法等方面进行综述,以期为玉米核不育机制研究与雄性不育技术产业化应用提供方法学指导。     

玉米花药培养和单倍体育种的研究新进展

利用花药培养获得单倍体,从而加速育种进程,是一顶新兴的生物技术,目前在玉米育种中广泛应用,本文综合近几年来国内外玉米的花药培养、单位体育种以及基因工程等方面的研究进展,重点对影响玉米花药培养效率的诸多因素进行了详细论述,并讨论了利用单7保体植株进行基因转导的潜力。     

玉米花药培养和单倍体育种的研究新进展

利用花药培养获得单倍体,从而加速育种进程,是一项新兴的生物技术,目前在玉米育种中广泛应用。本文综合近几年来国内外玉米的花药培养、单倍体育种以及基因工程等方面的研究进展,重点对影响玉米花药培养效率的诸多因素进行了详细论述,并讨论了利用单倍体植株进行基因转导的潜力。     

Tolerance to Zinc Deficiency in Rice Correlates with Zinc Uptake and Translocation

To study variation in zinc efficiency (ZE) among current Chinese rice genotypes, a pot experiment was conducted with 15 aerobic and 8 lowland rice genotypes. Aerobic rice is currently bred by crossing lowland with upland rice genotypes, for growth in an aerobic cultivation system, which is saving water and producing high yields. A Zn deficient clay soil was used in our screening. Zn deficiency resulted in a marked decrease in shoot dry matter production of most genotypes after 28 days of growth. Genotypes were ranked according to their tolerance to Zn deficiency based on ZE, expressed as the ratio of shoot dry weight at Zn deficiency over that at adequate Zn supply. Substantial genotypic variation in ZE (50–98%) was found among both lowland and aerobic genotypes. ZE correlated significantly (P < 0.05) with Zn uptake (R ² = 0.34), Zn translocation from root to shoot (R ² = 0.19) and shoot Zn concentration (R ² = 0.27). The correlation with seed Zn content was insignificant. In stepwise multiple regression analyses, variation in Zn uptake and Zn translocation explained 53% of variation in ZE. Variation in Zn uptake could be explained only for 32% by root surface area. These results indicate that Zn uptake may be an important determinant of ZE and that mechanisms other than root surface area are of major importance in determining Zn uptake by rice.     

Effects of Boron Deficiency on Anther Development and Floret Fertility in Wheat (Triticum aestivum L. 'Wilgoyne')

Boron (B) deficiency limits reproductive growth more than vegetativegrowth in cereals such as wheat. The purpose of the presentstudy was to identify the critical stages of anther developmentof wheat (‘Wilgoyne’) during which B deficiencycauses a significant and irreversible decrease of floret fertilityin order to formulate timely measures for correcting or preventingthis problem. Withdrawing B from the rooting medium for 3 dbetween premeiotic interphase through meiosis to late tetrad,limited anther elongation and resulted in the loss of pollenviability. The negative effects of B withdrawal on anther lengthsuggest that the role of B in reproductive cell walls is similarto that in vegetative ones. The results indicated that as moreflorets reached meiosis within the period of B withdrawal, thelower was floret fertility and the number of grains set in awhole ear. For the whole ear, the critical period during whichB deficiency causes maximal and irreversible damage to floretfertility was about 7 d, extending from the early emergenceof the flag leaf to 2–3 d after its full emergence. Theresults suggest that there are two phases of pollen developmentsensitive to boron deficiency: the period from premeiotic interphasethrough meiosis to late tetrad was the most sensitive stageof microsporogenesis in wheat while the period from mitosis-Ito II during which starch accumulation occurred in pollen grainswas less sensitive. Copyright 2000 Annals of Botany Company Anther, boron (B) deficiency, floret fertility, Grain Set Index (GSI), pollen, wheat (‘Wilgoyne’)     

Characterization of the Arrest in Anther Development Associated with Gibberellin Deficiency of the gib-1 Mutant of Tomato

The role of gibberellins in flower bud development was investigated by studying the gib-1 mutant of tomato, Lycopersicon esculentum. This gibberellin-deficient mutant initiates flower buds, but floral development is not completed unless the mutant is treated with gibberellin. Treatment with other plant growth regulators does not induce normal flower development. Development of gib-1 flower buds, as measured by progress toward anthesis, ceases at a bud length of 2.5 millimeters; however, increase in size of the bud continues. Buds between 2.5 and 3.7 millimeters are developmentally arrested but still are capable of developing normally after treatment with gibberellic acid. Anthers of these developmentally arrested buds contain pollen mother cells that are in the G1 phase of premeiotic interphase. Following treatment of developmentally arrested buds with gibberellic acid, premeiotic DNA synthesis and callose accumulation in pollen mother cells are evident by 48 hours posttreatment, and within 66 hours, prophase I of meiosis- and meiosis-related changes in tapetum development are observable.     

Zinc Deficiency Promotes Testicular Cell Apoptosis in Mice

Biological Trace Element Research - Zinc (Zn) plays an important role in spermatogenesis, and carbon tetrachloride (CCl4) induces testicular oxidative damage and cell death. The objective of the...     

Zinc Deficiency Is Common in Several Psychiatric Disorders

Background

Mounting evidence suggests a link between low zinc levels and depression. There is, however, little knowledge about zinc levels in older persons with other psychiatric diagnoses. Therefore, we explore the zinc status of elderly patients suffering from a wide range of psychiatric disorders.

Methods

Clinical data and blood samples for zinc analyzes were collected from 100 psychogeriatric patients over 64 of age. Psychiatric and cognitive symptoms were assessed using the Montgomery and Aasberg Depression Rating Scale, the Cornell Scale for Depression in Dementia, the Mini-Mental State Examination, the Clockdrawing Test, clinical interviews and a review of medical records. In addition, a diagnostic interview was conducted using the Mini International Neuropsychiatric Interview instrument. The prevalence of zinc deficiency in patients with depression was compared with the prevalence in patients without depression, and the prevalence in a control group of 882 older persons sampled from a population study.

Results

There was a significant difference in zinc deficiency prevalence between the control group (14.4%) and the patient group (41.0%) (χ² = 44.81, df = 1, p<0.001). In a logistic model with relevant predictors, zinc deficiency was positively associated with gender and with serum albumin level. The prevalence of zinc deficiency in the patient group was significantly higher in patients without depression (i.e. with other diagnoses) than in patients with depression as a main diagnosis or comorbid depression (χ² = 4.36, df = 1, p = 0.037).

Conclusions

Zinc deficiency is quite common among psychogeriatric patients and appears to be even more prominent in patients suffering from other psychiatric disorders than depression.

Limitations

This study does not provide a clear answer as to whether the observed differences represent a causal relationship between zinc deficiency and psychiatric symptoms. The blood sample collection time points varied in both the control group and the patient group. No data regarding zinc supplementation were collected.     

Reference Values for Serum Zinc Concentration and Prevalence of Zinc Deficiency in Adult Iranian Subjects

Zinc, as an essential trace element for health, plays various biological roles in human body functions. Serum zinc reference values are essential for assessing zinc-associated abnormalities and the prevalence of zinc deficiency. This study aims at determining age- and sex-specific reference values for serum zinc concentrations in adult Iranian subjects. Serum zinc concentration was measured by flame atomic absorption spectrometry in 4,698 adult subjects, aged 20?C94?years, randomly selected from the population of the Tehran, Lipid, and Glucose Study. After application of exclusion criteria, reference values for serum zinc were determined in 2,632 apparently healthy subjects according to guidelines of the International Federation of Clinical Chemistry (nonparametric method). Dietary zinc was assessed in 2,906 individuals, of which 1,685 were healthy subjects, using a validated semiquantitative food frequency questionnaire. Reference values for serum zinc concentrations ranged between 9.6 and 31.6, 8.9 and 29.9, and 9.3 and 30.8???mol/L in men, women, and the total population, respectively. Prevalence of serum zinc deficiency was 3.0 and 2.4?% in men and women, respectively (p?=?0.267); in men, but not in women, the prevalence increased significantly with age (p for trend <0.001). Of the total participants, 10.3?% (6.5 men and 3.8?% women, p?<?0.01) had lower zinc intake compared to dietary reference intakes. The zinc density of the population was 6.3?mg/1,000?kcal. In conclusion, this study presents reference values for serum zinc concentration in adult Iranian subjects for both sexes and different age groups. Prevalence of serum zinc deficiency and dietary zinc inadequacy seems to be lower in Iranians, compared to some other populations.     

菠萝蜜花药发育及花粉萌发研究

研究花药发育过程和花粉萌发条件是菠萝蜜稳产优质的基础。采用石蜡切片和离体培养的方法,对菠萝蜜花药的发育和花粉萌发进行了研究,结果表明：菠萝蜜的花药有4个花粉囊;减数分裂的胞质分裂有连续型和同时型两种形式,形成了等双面体排列和四面体排列的四分体;成熟花药的表皮细胞积累有大量的单宁。160 g·L^-1的蔗糖和0.25 g·L^-1的硼酸混合溶液对菠萝蜜花粉萌发具有明显的促进作用,CaCl₂对菠萝蜜花粉萌发作用不明显。     

The Effect of Severe Zinc Deficiency and Zinc Supplement on Spatial Learning and Memory

Zinc deficiency during pregnancy and during lactation has been shown to impair cognitive function and motor activity in offspring rats. In the present study, the effect of zinc deficiency and zinc supplement on spatial learning and memory in Morris Water Maze (MWM) and motor activity in open field were investigated. Pregnant rats after mating were divided to three groups. Control group fed a standard diet and a zinc deficient (ZnD) group fed a diet deficient in zinc (0.5–1.5 ppm) and a zinc supplement (ZnS) group fed a standard diet and enhanced zinc in the drinking water (10 ppm). All the diets were exposed during the last trisemester of pregnancy and during lactation. Rat’s offspring in these groups were tested for spatial learning and memory in MWM at post natal day (PND) 56 and were tested for motor activity in open field at PND 66.The Escape Latency (EL) and Traveled Distance (TD) in the ZnD group were increased but Percentage of Time Spent in the target quadrant (PTS) was decreased compared to the control group. In addition, these were no significant differences in EL and TD, but PTS had significant increase in ZnS compared to the control group. In the open field, Total Distance Moved (TDM) and Time of Motor Activity (TMA) for the ZnD were decreased compared to the control group, but there were no significant differences in TDM and TMA between control and ZnS groups. These findings suggest that zinc deficiency during the last trimester of pregnancy and during lactation impaired spatial learning and memory in their offsprings and has also negative effect on motor activity. In addition, ZnS has a significant effect on spatial learning and memory but no effect on motor activity in their offsprings.     

珍稀濒危植物十齿花属的花药发育和雄配子体发生及其系统学意义

十齿花属（Dipentodon）为东亚特有单型属,是国家二级保护植物,其系统位置长期有争议。本研究连续三年的野外观察结果表明十齿花（Dipentodon sinicus）的结籽率较低（4.31%）。同时利用常规石蜡制片技术,观察了十齿花的花药发育和雄配子体发育过程。十齿花的花药四室,花药壁发育类型为基本型。成熟花药壁有6层,由表皮,药室内壁,2层中层和2层绒毡层组成,绒毡层为腺质绒毡层。花药成熟时,纤维状加厚发生于药室内壁,便于花药开裂散粉。小孢子母细胞减数分裂的孢质分裂方式为同时型,小孢子四分体多为四面体型,稀左右对称型。成熟花粉粒为二细胞型,具3孔沟。在小孢子发育的减数分裂、小孢子四分体和二细胞型花粉时期,观察到发育不正常的现象,分别占40%、48%和36%。通过与其他亲缘类群的胚胎学特征比较,支持最新分子系统学把它独立成科,放在十齿花目的观点。雄配子体发育过程中,十齿花存在着花粉败育现象,这可能是导致其结实率低的原因之一。     

The Mechanics of the Grass Flower: Anther Dehiscence and Pollen Shedding in Maize

In this paper on the flower mechanics of the grasses, the openingmechanism of the maize anther is studied. Both the septum betweeneach two locules and the stomium of these porate-dehiscing anthersappear to be opened due to lysis of the middle lamellae of theircells. Additional mechanical force of the expanding pollen mightbe necessary to completely dissociate the parenchyma cells ofthe septum. A number of hours before anthesis the anther isstructurally able to dehisce. At anthesis the dehydrating endotheciumcells bend the locule walls bordering the pore in outward direction.Presumably evaporation is not the only cause for this dehydration. Poaceae; Zea mays ; flower; anther; dehiscence; endothecium; pollen     

Ecotypes of Holcus lanatus Tolerant to Zinc Toxicity also Tolerate Zinc Deficiency

Genotypes tolerant to zinc (Zn) toxicity, if they accumulateZn in their roots, may grow better than Zn-sensitive genotypes,even in Zn-deficient soil. In the present study, Holcus lanatusL. ecotypes differing in tolerance to Zn toxicity were grownin Zn-deficient Laffer soil which was amended with Zn to createa range of conditions from Zn deficiency to Zn toxicity. IncreasingZn additions to the soil, up to the sufficiency level, improvedgrowth of all ecotypes. At toxic levels of added Zn, the Zn-sensitiveecotype suffered a greater decrease in growth than the Zn-tolerantecotypes. All ecotypes accumulated more Zn in roots than inshoots, with root concentrations exceeding 8 g Zn kg^-1dry weightin extreme cases. When grown in Zn-deficient or Zn-sufficientsoil (up to 0.5 mg Zn kg^-1soil added), ecotypes tolerant toZn toxicity took up more Zn, grew better and had greater rootand shoot Zn concentration than the control (Zn-sensitive ecotype).Zn-tolerant ecotypes transported more Zn, copper (Cu) and iron(Fe) from roots to shoots in comparison with the Zn-sensitiveecotype. The average Zn uptake rate from Zn-deficient soil (noZn added) was greater in the Zn-tolerant ecotypes than in theZn-sensitive ecotype. In conclusion, ecotypes of H. lanatusthat are tolerant to Zn toxicity also tolerate Zn deficiencybetter than the Zn-sensitive ecotype because of their greatercapacity for taking up Zn from Zn-deficient soil. This is thefirst report of the coexistence of traits for tolerance to Zntoxicity and Zn deficiency in a single plant genotype. Copyright2000 Annals of Botany Company Copper, heavy metal, Holcus lanatus, iron, zinc deficiency, zinc toxicity