腐植酸对植物生理活动的影响

本文介绍了腐植酸的形成、提取、分类以及活性基团等方面的特征。腐植酸能影响植物的多种生理活动,包括植物的生长、营养元素的吸收、蛋白质和核酸的合长、光合作用、呼吸作用以及有些酶的活性等。腐植酸对植物的这些作用受自身不同成分、浓度、植物种类、外界营养条件等多方面的影响。本文也从细胞或分子水平讨论了腐植酸促进植物生长、影响营养元素吸收促进呼吸作用的机理。     

植物对水分胁迫的反应和适应性——Ⅱ植物对干旱的反应和适应性

干旱对植物的影响是非常广泛而深刻的。它的影响可以表现在生长发育的各个阶段,如萌发、营养生长和生殖生长,直到具体的生理代谢过程,如光合作用、呼吸作用、水和营养元素的吸收和运输、一些酶的活力     

植物在湿地养分循环中的作用

植物是湿地生态系统的重要组成部分之一,在养分循环过程中起着重要的作用。植物通过自身的生长代谢吸收湿地中的营养元素,但植物对营养物质的吸收能力随植物种类、群落组成及季节不同而存在差异;不同植物以及植物的不同器官对营养元素的累积特征存在显著差异,并随生长节律表现出明显的季节动态;植物本身的化学组成和特征制约着枯落物的分解和矿化过程,从而影响植物的养分归还。本文从植物对湿地营养元素吸收、累积以及养分归还方面总结了植物在湿地养分循环中的作用,指出目前研究中存在的不足,并对今后的研究提出一些建议。     

植物硅营养的研究进展

阐述了植物吸收硅的机理、硅与其它营养元素的关系及其对非胁迫和胁迫条件下植物生长发育的有益作用 .植物吸收硅的机制目前尚不是很清楚 ,不同植物吸收硅的方式不同 .硅可影响植物中其它营养元素的含量 .在非胁迫条件下 ,硅可促进植物的生长 ;硅也参与了植物抗病、抗虫等生物胁迫 ,以及抗金属毒害、盐害、温度胁迫、干旱、抗倒伏等非生物胁迫的反应 .目前 ,应从多种植物上深入研究硅的吸收方式与机理 ;同时 ,应该改变硅在细胞壁的沉积仅仅起增强组织机械强度作用的观点 ,而应从生理代谢调控的角度进行硅作用机制的研究 ,为生产实践中硅肥的应用奠定理论基础     

植物硅营养的研究进展

阐述了植物吸收硅的机理、硅与其它营养元素的关系及其对非胁迫和胁迫条件下植物生长发育的有益作用。植物吸收硅的机制目前尚不是很清楚,不同植物吸收硅的方式不同。硅可影响植物中其它营养元素的含量。在非胁迫条件下,硅可促进植物的生长;硅也参与了植物抗病、抗虫等生物胁迫,以及抗金属毒害、盐害、温度胁迫、干旱、抗倒伏等非生物胁迫的反应。目前,应从多种植物上深入研究硅的吸收方式与机理;同时,应该改变硅在细胞壁的沉积仅仅起增强组织机械强度作用的观点．而应从生理代谢调控的角度进行硅作用机制的研究,为生产实践中硅肥的应用奠定理论基础。     

微生物肥料作用机理的研究新进展

综述了近几年国内外有关微生物肥料研究与应用的文献,系统阐述了微生物肥料的作用及其研究进展.涉及微生物肥料的作用主要有产生和协助植物对营养元素的吸收、产生多种生理活性物质刺激调节植物生长、产生抑病作用间接促进植物生长、提高植物抗逆能力、改善农作物产品的品质等以综合作用来降低化肥用量的效应等.指出微生物肥料的功效和发展趋势,为进一步开发和应用微生物肥料提供依据.     

九连小檗悬浮培养细胞生理生化特性的研究 Ⅴ．细胞生长与呼吸作用及对主要营养元素吸收、消耗的关系

叙述了九连小檗细胞悬浮培养中细胞生长与呼吸作用及对主要营养元素吸收消耗的关系。细胞接种于新鲜培养液中,呼吸作用强度和对主要营养元素的吸收、消耗便迅速增加。接种后第６天,培养液中ＰＯ４３－几乎被耗尽,Ｋ＋和ＮＯ３－的浓度也减少一半,细胞生长由延迟期进入起始生长期。至第８天呼吸强度达到高峰,细胞生长加速,但细胞生长高峰延迟于呼吸高峰。随后,营养物质的消耗减少,呼吸降低,生长减慢。至静止期细胞生长停止,呼吸作用微弱。这些结果为优化培养条件,改进培养基组成,调控细胞生长和代谢提供了参考。     

九连小檗悬浮培养细胞生理生化特性的研究 Ⅴ．细胞生长与呼吸作用及对主要营养元素吸收、消耗的关系

叙述了九连小檗细胞悬浮培养细胞生长与呼吸作用及对主要营养元素吸收消耗的关系。细胞接种于新鲜培养液中,呼吸作用强度和对主要营养元素的吸收,消耗便迅速增加。接种后第６天,培养液中ＰＯ４＾３＾－几乎被耗尽,Ｋ＾＋和ＮＯ３的浓度也减少一半,细胞生长由延迟期进入起始生长期。至第８天呼吸强度达到高,细胞生长加,但细胞生长高峰延迟于呼吸高峰。随后,营养物质的消耗减少,呼吸降低,生长减慢,至静止期细胞生长停止,呼     

外源输入氮的有效性及形态对植物生长与生理影响的研究进展

氮(N)是控制植物结构和功能以及维持生态系统稳定的重要营养元素之一,外源输入氮素的有效性及形态的差异对植物的生长发育和生理特征产生显著的影响。由于全球气候变化和人类活动的干扰,大气氮沉降量日益增加,氮形态也发生改变,严重破坏植物的正常生长和生态系统的平衡稳定,已成为研究学者关注的热点问题。本文综述了不同氮输入水平和形态对植物的生长、光合作用、养分吸收以及代谢酶活性等方面的影响,归纳出：(1)适量氮输入能促进植物生长、光合作用和养分吸收能力,但当超出植物承受的阈值后,则对其产生抑制作用;(2)由于植物对氮素形态吸收偏好的差异,铵态氮(NH₄⁺-N)和硝态氮(NO₃^--N)对植物的生长、光合作用、养分吸收以及代谢酶活性的影响效果不同,且适宜铵硝配比相较于单一某种氮素添加对大多数植物的促进作用更显著。提出未来的研究方向应着重考虑4个方面：(1)开展大尺度的长期监测控制实验;(2)利用分子生物学技术深入探究氮形态对植物影响的微观机理;(3)重点关注土壤根际环境对植物根系氮素吸收的影响;(4)综合分析氮输入与...     

与高等植物吸收NO^—3／NH^＋4,PO^3—4和K^＋有关的膜转运蛋白编码？…

高等植物对土壤中营养元素的吸收是其一切生命活动过程的基础，尤其在营养元素缺乏的状态下，更与其抗营养饥饰物等特性息息相关。兼于土壤中Ｎ、Ｐ、Ｋ元素缺元的严重性与普遍性，以及Ｎ、Ｐ、Ｋ对高等植物生长和发育的重要性，有关高等植物吸收营养元素的膜转运蛋白编码基因的分子生物学研究已引起有关学者的高度重视。     

植物的硅素营养研究综述

本文阐述了硅在植物中的形态、分布、吸收、积累、生理作用及其与其它元素的关系。研究表明：1．硅主要以二氧化硅胶(SiO2.nH2O)的无机物形态存在于植物表皮细胞和细胞壁。植物体内硅的含量在不同物种间差异很大。根据硅的含量,可将一般栽培植物分为三种类群;同时根据植物硅钙摩尔比值可将植物分为喜硅植物和非喜硅植物。硅在植物各部分分布不均匀,并且随着植株的生长发育,植株中的硅含量不断变化。植物中硅的积累受环境中多种因素的影响。2．植物主要以单硅酸形态吸收硅,不同植物吸收硅的能力不同。水稻具有主动吸硅能力,其吸收过程受体内代谢活动影响<请合法使用软件>其它大多数植物主要以被动方式吸收硅,但不排除具有选择性吸收硅的可能性。3．硅对植物的生长发育产生影响。硅是一些植物(如禾本科植物、甜菜、木贼属植物及某些硅藻)的必需元素。硅对其它很多植物具有有益作用。硅对植物的作用主要表现在对形态结构、生理过程和抗逆能力三方面的影响 上。在去硅条件下,多种植物表现出缺硅症状。4．硅对植物吸收利用对其它营养元素产生影响。硅对不同元素的影响方式和程度不同,同时随着植物的生长发育,对某种元素的作用常发生变化。     

Effects of Stress Modifier Biostimulants on Vegetative Growth,Nutrients, and Antioxidants Contents of Garden Thyme (Thymus vulgaris L.) Under Water Deficit Conditions

The aim of this study is to investigate the effect of stress modulators on vegetative growth, antioxidants, and nutrient content of Thymus vulgaris L. under water deficit stress conditions. A factorial experiment was performed in the form of a randomized complete block design with 10 treatments and 3 replications in the 2019–2020 growing season. The factors were stress modulators at 5 levels (ZN: zinc nano-fertilizer, AA: amino acid, SW: seaweed, HA: humic acid and C: control) and irrigation regime at 2 levels [FIrr: full irrigation (100% field capacity) and DIrr: deficit irrigation (50% field capacity)]. The highest plant height, number of branches, and total dry weight of the garden thyme plant were observed in the foliar application of HA and SW under full irrigation conditions. Relative water content, chlorophyll a and b, and uptake of nutrients (N, P, and K) were reduced under water deficit stress, but the foliar application of stress modulators increased relative water content, chlorophyll content, and nutrient uptake of the garden thyme plant significantly compared with control. The water deficit increased proline content, total flavonoid, and phenol content in the garden thyme plant. So, the highest total flavonoid and phenol content was obtained from plants treated with HA, whereas proline content was higher in the control plants. Soluble sugars and essential oil increased significantly under water deficit stress conditions. The foliar application of HA compared to the control plant increased soluble sugars and essential oil in garden thymes. The activities of catalase, superoxide dismutase, and ascorbate peroxidase enzymes were improved in stress modulator treatments such as HA and SW compared to control plants under water deficit stress conditions. The plants of garden thymes showed a good response to stress modulator treatments under water stress conditions, and HA and SW treatments were found to be more effective.

     

A theoretical explanation of the Piper-Steenbjerg effect

The relation between plant yield and plant nutrient concentration is sometimes found to be negative, a phenomenon called the Piper-Steenbjerg (PS) effect. A model was used to examine the underlying causes of the PS effect, and the conditions under which it is most likely to occur. The model uses the nutrient productivity concept for plant growth and a nutrient uptake equation in which root growth rate and external nutrient concentration determine the uptake rate. The study suggests that the PS effect occurs when the fast growth of plants grown in an initially higher nutrient medium eventually leads to a more rapid depletion of external nutrients than the slow growth of plants grown in an initially lower nutrient medium. The fast growth of plants combined with a rapid decrease of nutrient uptake leads to a fall in plant nutrient concentration. When these large plants with very low nutrient concentrations are compared with the smaller, slow-growing plants, a PS effect may be found depending on the time at which the plants are harvested, and on the range of initial values of the external nutrient content. When it occurs, the effect is greatest when the depletion volume per unit new root (V_d) is lowest, and when the mobility of nutrients in the medium is highest (α=1). The results are sufficiently general to apply to a variety of nutrients, plant species and growth media.     

Energy metabolism of Plantago lanceolata as dependent on the supply of mineral nutrients

Plantago lanceolata L., a grassland species from a relatively nutrient-poor habitat, was grown in nutrient-rich and in nutrient-poor culture solutions. Half of the plants were trensferred from high to low or from low to high nutrient conditions. Shoot growth was immediately reduced upon transfer to low nutrient conditions, whilst it reacted more slowly upon transfer of plants to high nutrient conditions. Root growth was less dependent on the supply of nutrients, but it was slightly reduced upon transfer of plants to high nutrient conditions.
Photosynthesis was largely independent of the nutrient supply, apart from an initial increase upon transfer of plants to low nutrient conditions. Photosynthesis decreased with age in all treatments, and this decrease was not due to mutual shading. The decrease of photosynthetic rate was not accompanied by a decreased relative growth rate: it was compensated by a more efficient root respiration, since the activity of the alternative nonphosphorylating pathway continuously decreased in plants grown in a high nutrient environment.
It is concluded that the alternative pathway was of significance in removal of carbohydrates, which could not be utilized for growth, energy production, etc. , due to a temporary or structural imbalance between assimilate production and requirement. The alternative pathway also appeared to allow P. lanceolata plants to adapt to a changed environment as regards mineral nutrition.
The experimental value for root growth respiration of P. lanceolata grown under high nutrient conditions was compared with a theoretical value, calculated from the biochemical composition of plant dry matter and the known energy costings for biosynthetic and transport processes. A good correlation between the experimental and theoretical value of root growth respiration was found if it was assumed that ion uptake required c . 1.0 molecule of ATP per ion per membrane passage.     

植物低氧胁迫伤害与适应机理的研究进展

不良的通气条件导致了正常生长发育的植物生理性缺氧,低氧胁迫是高等植物主要的非生物胁迫因素之一。本文综述了低氧胁迫对植物生长、植株形态的影响,低氧胁迫对植物内部水分、养分吸收的变化,呼吸代谢途径的变化、激素代谢的变化,氧化系统的变化的影响,以及低氧胁迫过程中植物体内信号的传导、基因的表达、蛋白质的合成等,在不同层面分析了低氧胁迫对植物的伤害及植物对低氧逆境适应机理的最新研究成果。     

Potassium and phosphate uptake of cucumber plants at different ammonia supply

Summary Experiments on cucumber plants grown in nutrient solution were conducted in order to study long and short time effects of ammonia on growth, nutrient element uptake and respiration of roots.Shoot yield and potassium concentration in tissue of plants treated 18 days with varied ammonia concentration were decreased. However, it was not assumed that K deficiency caused the yield reduction. The ammonia effect on K content was more pronounced in roots than in shoots.The decreased K concentration of plant tissue was linked to a diminished ability of plant roots to absorb potassium. The maximum rate of potassium uptake was lowered by ammonia during both, long- and short-time treatment. The results indicated that the NH₃ influence on potassium uptake was due to effects on metabolism and permeability of roots because changes of K uptake rate occurred immediately after starting the NH₃ treatment. Furthermore, it is shown that ammonia inhibited respiration of roots.During the short-time treatment net potassium efflux of roots was observed at higher NH₃ concentrations. The extent of K efflux depended on K concentration of both, root tissue and nutrient solution.Pretreating the plants for 12 hours with ammonia also resulted a decline in K uptake rate. However, plant roots subjected to ammonia concentrations up to 0.09 mM completely recovered during 24 hours after removing the NH₃ treatment whereas at higher NH₃ concentrations only a partial recovery occurred.Furthermore, it was shown that ammonia also influenced P uptake by plant roots.     

Gas exchange and nutrition patterns during the life cycle of an artificial wheat crop

The growth, mineral and shoot and root CO₂ exchange of wheat plants ( Triticum aestivum L. cv. Courtot) cultivated in growth chambers have been studied during the complete life cycle. The life cycle could be divided into 4 periods according to the patterns of CO₂ exchange: exponential increase, linear increase, stabilization and decline of photosynthesis. These patterns are analysed in relation to light interception, tillering, competition between plants and ageing of the leaves, all of which constitute successive limiting factors. Root metabolism seemed to be subordinated to the demand of the shoot for minerals. Ion uptake from the nutrient solution was particularly pronounced in young plants, which were higher in minerals and nitrogen than older ones. The ratios of K and P uptake varied with plant age, and the charge balance in ion exchange was equlibrated by H uptake. Rhythmic patterns appeared in all exchanges and varied with plant age. The highest amplitude of rhythm was found in root respiration. After taking the losses due to respiration and photorespiration into account, the maximum rate of photosynthesis approached the theoretical value calculated from the light energy absorbed.     

The effect of mineral nutrition on the growth and maintenance components of respiration during heterotrophic growth of barley seedlings

Spring barley seedling were grown in the dark for 21 d and respiration rates of the whole plant (including the seed), of the shoots, and of the roots were determined. A function describing the growth and maintenance components of respiration was interpolated through the experimental points and its parameters in plants under different mineral nutrition were compared. The plants grown in a complete nutrient solution showed the highest growth rate in the initial phase of development and thus reached the maximum respiration rate earlier than plants in the other variants. The highest proportion of substrate was respired in the shoot. Plants grown under deficiency of phosphorus and magnesium had a slower respiration rate than plants grown in the complete nutrient solution (NP), whereas the amount of respired substrate in plant parts was similar to that recorded in the NP plants. Plants grown in distilled water showed the lowest growth efficiency and respirated the highest proportion of substrate in the root.     

稀土元素对植物的生物效应及其作用机理

综述了稀土元素对植物根系发育、生物量、品质和抗逆性的影响.适量稀土浓度可促进植物生长,提高种子萌发能力和根系发育,提高植物生物量,并改善植物果实的品质.施用适量稀土元素还可以增强植物的抗逆性并且对一些植物病害有一定防治作用.介绍了植物对稀土元素的吸收特性和稀土元素在植物体内的含量、分布、存在形式及细胞定位.重点探讨了稀土元素对植物光合作用、叶绿素形成、植物吸收营养元素、稀土元素与钙相关性和稀土元素对细胞膜及酶的作用机理,内容包括稀土元素可提高植物叶绿素含量,增强光合效率,从而增加植物生物量.适量的稀土元素能够促进植物对营养元素的吸收、转化和利用.稀土元素有类似钙的功能,可置换出酶中的钙离子而参与酶的反应.稀土离子可以维持细胞膜的透性和稳定性,提高膜的保护功能,增强植物对不良环境的抵御能力.最后,对稀土元素的研究前景进行了展望.