Growth Of Young Plants Research Articles

Мониторингфауны мангровых посадок залива Дам Бай (О. Че, залив Ня-Чанг)

Monitoring of fauna in mangrove plantations is extremely important for understanding developmental patterns of mangrove ecosystems, which contributes to conservation, rehabilitation and sustinable management issues of this economically and ecologically valuable system. In Dam Bay on a mud flat fringed by narrow belt of Rhizophora apiculata, seedlings of the same species were planted in 2005 and 2009. Dynamics of species richness, species composition and density of macro invertebrate fauna were recorded in newly planted mangrove association during ten years. Comparison between the fauna of mangrove plantings at Dam Bay and natural association in Nha Phu Bay was conducted. For those purposes quantitative and qualitative samples were collected from year 2005 to 2015 for Dam Bay, and years 2012 and 2014 for Nha Phu. The most diverse groups of invertebrates were gastropods, bivalves and crabs in both natural and planted mangroves. Faunal richness and quantitative characteristics altered significantly during monitoring period in newly planted mangrove association. We recorded the growth of species richness and density of eurybiotic and opportunistic species, due to the enrichment of the sediments by organic matter and appearance of new hard substrata. At the beginning of 2008, we observed progressive colonization of the plantation by specialized mangrove species, the main reasons were the growth of young plants and as a result gradual complication of vegetation structure. Nevertheless even after 10 years the plantation has lower species richness of specialized fauna than the natural association in Nha Phu. The structure of fauna i.e. proportion of specialized versus eurybiotic species and their abundance may be used as indicators of condition of mangrove associations.

扎龙湿地不同生境芦苇种群根茎数量特征及动态

PDF HTML阅读 XML下载 导出引用 引用提醒 扎龙湿地不同生境芦苇种群根茎数量特征及动态 DOI: 10.5846/stxb201703200469 作者: 作者单位: 齐齐哈尔大学 生命科学与农林学院,齐齐哈尔大学 生命科学与农林学院,齐齐哈尔大学 生命科学与农林学院,齐齐哈尔大学 生命科学与农林学院,东北师范大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31472134，31672471）；黑龙江省教育厅科学技术研究项目（12541887） Quantitative characteristics and dynamics of the rhizome of Phragmites australis populations in heterogeneous habitats in the Zhalong Wetland Author: Affiliation: College of Life Science and Agriculture,Forestry ,Qiqihar University,College of Life Science and Agriculture,Forestry ,Qiqihar University,College of Life Science and Agriculture,Forestry ,Qiqihar University,College of Life Science and Agriculture,Forestry ,Qiqihar University,Northeast Normal University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:采用单位土体取样，计测长度和生物量的调查与统计方法，对扎龙湿地保护区4个生境芦苇种群根茎数量特征进行比较分析。结果表明，芦苇5月10日左右返青后进入营养生长期，根茎长度6-8月份缓慢增加，8-10月份显著增加，后期是前期的3.5-10.3倍，生长季中后期是种群新根茎补充和生长的主要时期，不仅实现了种群空间扩展，并为营养繁殖储备更多繁殖芽；根茎生物量和干物质贮量6-8月份逐渐减少，8-10月份又逐渐增加，均以生长季末期的10月份最大，并均显著地（P < 0.05）高于其他月份，种群根茎养分的消耗主要供给根茎芽的萌发和幼株生长，根茎养分的储藏又为翌年种群的更新及扩展提供物质保障，种群对地下根茎存在明显的养分"超补偿性"贮藏现象。种群根茎长度和生物量均以湿生生境最大，依次为旱生生境、水生生境，盐碱生境最小，根茎干物质贮量以旱生生境最大，依次为湿生生境、水生生境，盐碱生境最小。种群根茎长度与返青后实际生长时间之间均较好地符合直线函数关系，种群根茎生物量和干物质贮量与生长时间之间较好地符合二次曲线函数关系，R2在0.804-0.997之间，拟合方程均达到了显著或极显著（P < 0.01）水平。4个生境芦苇种群在根茎长度、生物量、干物质贮量等数量特征均表现出由遗传因素控制的比较稳定的季节动态规律，在生境间的差异及其差异序位又均基本稳定，均表现出明显的土壤因子环境效应，其中土壤含水量、有机质、速效氮为正向驱动，pH、速效磷为负向驱动，土壤含水量、pH对根茎数量特征的驱动作用更突出。 Abstract:A comparative study of the quantitative characteristics of the rhizome of Phragmites australis populations in four habitats in the Zhalong Wetland was performed by sampling a unit volume of soil and measuring biomass and rhizome length. The results showed that P. australis returned green around May 10 and began to enter the vegetative growth period. There was a slow increasing trend in rhizome length from June to August, but a significantly increasing trend was observed from August to October. Moreover, rhizome length in the late period was 3.5-10.3 times higher than that in the early period. The middle and late growth seasons were the main periods of new rhizome supplement and growth of the population, during which time the spatial expansion of the population was achieved and more breeding buds were reserved for nutritional reproduction. Rhizome biomass and dry matter storage decreased gradually from June to August, but increased gradually from August to October, with the largest biomass observed in October, the end of the growth season, and was significantly higher than in other months(P < 0.05). The consumption of rhizome nutrients in the population mainly contributed to the germination of rhizome buds and the growth of young plants. The storage of rhizome nutrients also provided material support for the renewal and expansion of the population in the next year. The phenomenon of "super compensatory" storage in the rhizomes of the population was obvious. The length and biomass of rhizomes were the largest in the wet habitat, followed by the xeric, and aquatic habitats, however, they were the lowest in the saline-alkali habitat. The dry matter storage of rhizomes was the largest in the xeric habitat, followed by the wet and aquatic habitats, it was the lowest in the saline-alkali habitat. There was a significant, linear correlation between rhizome length of P. australis and the actual growth time after returning green. However, there was a significant, logarithmic correlation between rhizome biomass, dry matter storage, and the actual growth time after returning green, the goodness of fit of equation was 0.804-0.997, and the fitting equation reached a significant level of P < 0.01. The length, biomass, and dry matter storage of P. australis rhizomes in the four habitats showed relatively stable seasonal dynamics controlled by genetic factors during the growing period. The differences between the habitats and their differential orders were basically stable, showing significant environmental effects of soil factors, among which, the soil water content, organic matter, and available nitrogen were the positive drivers, while pH and available phosphorus were the negative drivers. The driving effects of soil water content and pH were the most prominent. 参考文献 相似文献 引证文献

Nitrogen fertilization in the growth phase of 'Chardonnay' and 'Pinot Noir' vines and nitrogen forms in sandy soil of the Pampa Biome

ABSTRACT Information on nitrogen fertilization in growing vines is still a very limited subject, especially for crops on sandy soils in the Pampa Biome in Rio Grande do Sul, where viticulture has expanded considerably in the last decade. This study aimed to assess the impact of N doses on growth of young plants of Chardonnay and Pinot Noir vines and N forms present in sandy soil in the Pampa Biome. The experiment was conducted from October 2011 to December 2012 in a vineyard in Santana do Livramento, in Southern Rio Grande do Sul State, in soil with 82 g kg-1 clay in the 0-20 cm layer. Vines of Chardonnay and Pinot Noir varieties were subjected to applications of 0, 10, 20, 40, 60, and 80 kg N ha-1 year-1. Total N in leaves, SPAD readings, stem diameter, plant height, and dry matter of the pruned material were evaluated in two growth cycles and three times. Soil samples were collected at 0-10 and 10-20 cm depths at four crop growth stages, in which N-NH4 +, N-NO3 -, and total N were analyzed and the mineral N was calculated. The N levels applied to young vines, although they did not provide relevant changes in the N-NH4 +, N-NO3 -, and mineral N contents in the soil, were able to increase the N content in the leaves, increasing plant vigor. because the reason is that there was an increase in stem diameter, plant height, and dry matter of pruned material in most evaluation periods. These parameters suggest better growth patterns and uniformity of young grapevines with possible positive effects in anticipation of production, demonstrating the importance of nitrogen fertilization strategies to the growing vines in the sandy soil conditions of the Pampa Biome.

Increased growth of Araucaria angustifolia under warm conditions is unaccompanied by increased photosynthetic performance

Although A. angustifolia occurs in regions with subtropical climate, warm conditions do not seem to impair the growth of young plants. The effects of increasing temperature are worth studying even in tree species from subtropical climates. Araucaria angustifolia occurs in the south and southeast of Brazil and in Argentina and its growth and success may be associated with low temperatures. We measured growth, photosynthetic parameters and the nutritional status of this plant growing under artificial warm and cool conditions. We expected growth and photosynthetic performance to increase under cool rather than warm conditions. Under high daily temperature, plants showed increased leaf area per plant, more leaves, containing more nitrogen. However, CO2 assimilation rates at light saturation were similar in plants grown under both conditions, and photosynthetic nitrogen use efficiency was 25% higher in plants under cool conditions. This may be the first report of temperature effects on the growth of this species. Despite enhancing growth in A. angustifolia, warm conditions do not directly influence photosynthetic activities, but enhance leaf area per plant allowing increased CO2 uptake.

The Effect of &amp;lt;i&amp;gt;Aphthona whitfieldi&amp;lt;/i&amp;gt; (Coleoptera: Chrysomelidae) Populations’ Density on the Growth of &amp;lt;i&amp;gt;Jatropha curcas&amp;lt;/i&amp;gt; in Burkina Faso

Aphthona whitfieldi Bryant (Coleoptera: Chrysomelidae) is a major insect pest of Jatropha curcas L. in Burkina Faso. This study aimed at evaluating the effect of the insect pest populations’ density on the growth of the plant. To achieve this purpose, 90-day aged single plants were caged in a randomized complete block design experiment with 5 treatments and 5 replicates. The treatments consisted of increasing numbers of adults of A. whitfieldi used to infest the caged plants: T0 (0 adult = check), T1 (100 adults), T2 (200 adults), T3 (300 adults), T4 (400 adults). All caged plants were infested 21 days after transplantation and the evaluation started 14 days later one on every 2-week basis from September 18, 2014 to February 19, 2015. The growth parameters of the plant were assessed. The results showed that the intensity of damage caused by A. whitfieldi on the growth of young plants of J. curcas varied according to the treatment (i.e., according to the number of adult individuals infesting the plant at the beginning). The higher the number, the heavier the level of damage caused by the pest. So, the growth of the J. curcas plant was inversely proportional to the number of A. whitfieldi infesting individuals. There was also a positive linear correlation between the defoliation rate and the height of the seedlings. The status of this insect pest was confirmed by the results of this study.

PERTUMBUHAN SAGU (Metroxylon sp) DI HUTAN ALAM PAPUA

Sago plants (Metroxylon sp) is a type of palm tree that grows around swamps and waterlogged land in the tropics. Sago palms grow on muddy land, with the quantity of water varies greatly, ranging from dry land to land remained logged. The longer the land flooded, the growth of young plants (shoots / seedling) very rapidly, but the growth of the trees are very slow. This study aims to determine the relationship of the growth of sago (Metroxylon sp) with climatic factors (humidity, temperature, light) and biotic (plants or other vegetation). The results showed that the relationship of growth of sago with environmental factors, edaphic (water), climatic (humidity, light) and biotic factors (vegetation) are generally water has an influence on the growth of sago while the humidity factor for all types of places to grow, that is, the area stagnant water, temporary areas and dry areas do not affect the growth of sago.

Eutrophication and warming-driven green tides (Ulva rigida) are predicted to increase under future climate change scenarios

The incidence and severity of extraordinary macroalgae blooms (green tides) are increasing. Here, climate change (ocean warming and acidification) impacts on life history and biochemical responses of a causative green tide species, Ulva rigida, were investigated under combinations of pH (7.95, 7.55, corresponding to lower and higher pCO2), temperature (14, 18°C) and nitrate availability (6 and 150μmolL−1). The higher temperature accelerated the onset and magnitude of gamete settlement. Any two factor combination promoted germination and accelerated growth in young plants. The higher temperature increased reproduction, which increased further in combination with elevated pCO2 or nitrate. Reproductive success was highest (64.4±5.1%) when the upper limits of all three variables were combined. Biochemically, more protein and lipid but less carbohydrate were synthesized under higher temperature and nitrate conditions. These results suggest that climate change may cause more severe green tides, particularly when eutrophication cannot be effectively controlled.

The yield of eggplant depending on climate conditions and mulching

Abstract The field production of eggplant in moderate climates is difficult as it depends heavily on thermal conditions. Eggplant is a species that is sensitive to low temperatures, and temperatures below 16°C constrain the growth of young plants. Other disadvantageous factors include: temperatures that are too high, water shortage and excessive soil humidity. The growth conditions for eggplant can be improved by using mulches. The purpose of the experiment was the assessment of eggplant cropping while using synthetic mulches of polyethylene foil and polypropylene textile. The research took five years (2008-2012) and on the basis of the obtained results it was possible to determine the influence of weather conditions on the yielding of this species. It was proven that eggplant cropping significantly depended on the air temperature and the amount of rainfall during the vegetation period. The highest yield was observed when the average air temperature was high and at the same time rainfall was evenly distributed throughout the vegetation season. It also turned out that the agro-technical procedure which significantly increased eggplant fruit cropping was mulching the soil with polyethylene black foil, or transparent foil, previously having applied a herbicide.

Pengaruh Pemupukan dan Mikoriza terhadap Pertumbuhan Tanaman Karet Muda Pada Model Peremajaan Bertahap

&lt;p&gt;Model peremajaan bertahap merupakan salah satu cara untuk meningkatkan produktivitas karet rakyat yang sudah tua dan rusak. Kelemahan dari model ini adalah tingginya keragaman pertumbuhan tanaman muda di lapangan. Penelitian bertujuan mengetahui pengaruh pemupukan ekstra dan pemberian mikoriza terhadap pertumbuhan tanaman karet muda dalam model peremajaan secara bertahap. Lokasi penelitian di Desa Ramsay, Kecamatan Way Tuba, jenis tanah podsolik merah kuning dengan klasifikasi iklim termasuk B2 menurut Oldemand, mulai tahun 2012 sampai tahun 2014. Penelitian dilakukan dengan rancangan petak terpisah. Sebagai petak utama adalah umur tanaman: P&lt;sub&gt;1&lt;/sub&gt; (umur 3 tahun), P&lt;sub&gt;2&lt;/sub&gt; (2 tahun), dan P&lt;sub&gt;3&lt;/sub&gt; (1 tahun). Sebagai anak petak adalah dosis pupuk: D&lt;sub&gt;1&lt;/sub&gt; (dosis 100% rekomendasi), D&lt;sub&gt;2&lt;/sub&gt; (dosis 100% rekomendasi + mikoriza), D&lt;sub&gt;3&lt;/sub&gt; (dosis 125% rekomendasi), dan D&lt;sub&gt;4&lt;/sub&gt; (dosis 125% rekomendasi + mikoriza). Pemberian pupuk dilakukan dua kali setahun, sedangkan mikoriza diberikan satu kali setahun pada akhir musim hujan. Bahan tanaman yang digunakan adalah klon karet PB 260, dengan teknik budidaya standar seperti penyiangan, bobokor, dan penyiraman pada saat musim kemarau. Peubah yang diamati adalah tinggi tanaman dan lilit batang. Hasil penelitian menunjukkan pemberian pupuk ekstra 25% dari rekomendasi yang ditambah dengan mikoriza mampu meningkatkan pertumbuhan tanaman karet yang tertinggal pertumbuhannya karena umur yang lebih muda. Dosis pupuk 125% dari rekomendasi + mikoriza dapat menghasilkan pertumbuhan tanaman umur 2 tahun sama dengan pertumbuhan tanaman umur 3 tahun yang dipupuk dengan dosis rekomendasi. Mikoriza bekerja secara sinergis dengan pupuk anorganik, dan mampu meningkatkan efektivitas dan efisiensi pemupukan ekstra pada model peremajaan karet secara bertahap.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Kata kunci: &lt;/strong&gt;Karet, pupuk, mikoriza, peremajaan&lt;/p&gt;&lt;p&gt;&lt;em&gt;Gradual rejuvenation model is an option to increase the productivity of smallholder rubber plantation due to old and damaged plants. The limitation of this model is the high variation of the growth of young plant in the field. This study aimed to determine the effect of extra fertilization and mycorrhiza on the growth of young rubber plants in the gradual rejuvenation model. The research was located at Ramsay Village, Way Tuba District, with red-yellow podzolic soil types and climate type of B2 according to Oldemand, from 2012 to 2014, and arranged in split plot design. The plant age, P1 (3 years old); P2 (2 years old); and P3 (1 year old) was denoted as the main plot, whereas the subplot is fertilizer dosage, D1 (100% of recommended dosage); D2 (100% of recommended dosage + mycorrhiza; D3 (125% of recommended dosage); D4 (125% of recommended dosage + mycorrhiza). Fertilizer application was done twice a year, while mycorrhiza were given once a year toward the end of the rainy season. The plant material used was PB 260 clone, with a standard agricultural practices such as weeding and watering during the dry season. Variables measured were plant height and girth. The results showed that application of 25% extra from the recommended dosage + mycorrhiza was able to accelerate the growth of young rubber plants. Fertilizer dose of 125% from the recommendation + mycorrhiza applied on 2-year-old plants exhibited the same growth with 3-year-old plant that treated with recommended dosage. This result indicates that mycorrhiza works synergistically with inorganic fertilizer, which enhances the effectivity and efficiency of extra fertilization in gradually rejuvenation models.&lt;/em&gt;&lt;/p&gt;

Growth Variation of Ebony (Diospyros Pilosanthera Blanco.) for 2 Years Old in Arboretum of Manado Forestry Research Institute

One commercial tropical species in North Sulawesiis ebony (Diospyrospilosanthera Blanco). This species is called Boniok by local people in Bolaang Mongondow. This species has wide distribution in Southeast Asiain cluding Indo-China, Burma, Thailand, PeninsularMalaysia, Sumatra, Java, Borneo(Sarawak, Brunei, Sabah, West, Central and East Kalimantan), Philippines, Celebes, the Moluccas and New Guinea. This species isone of commercial timber that has been exploited since long timeago and not equal to their natural regeneration, thus, causing their population decrease and are rarely found in the forest in North Sulawesi Province and Gorontalo Province. Nowadays, information about the number of their population in North Sulawesi Province and Gorontalo Province are not available. One of efforts to save this species is by doing exitu conservation. This studyaims to determine the growth of exitu conservation plant of ebony(D. pilosanthera) at 2 years old in Arboretum of Manado Forestry Research Institute. This study was done by randomized block design using 5 replications. Each replication consisted of 10 individuals and the number of samples used were 50 individuals. Spacing used is 3mx 3m. Treatment applied was dosage of fertilizes using Nitrogen, Phosphate and Kalium (NPK). Replication of treatments consists of 5 group i.e group 1(A0) was using 100gr/plant, group 2(A1) 200 gr/plant, group 3(A2) 300gr/plant, group 4 (A3) 400gr/plant and groups 5(A4) 500gr/plant. The results showed that their life percentage rate in 2years were 98.00%. The life percentage of ebony(D. pilosanthera) was high and indicates that these plants canada ptand grow wellout of their naturalhabit at. The results showed that statistical analysis at 95% interval confidence indicates that there is no significant difference between the treat mentsused in this research and the growth of its height and diameter. Otherwise, there is no significant difference betwen treatments, but they have difference growth permormance, while the best growth of height was shown by treatment A1 (200 gr/plant) with the average of 3.350 m and the lowest was shown by treatment A0(100gr/plant) with average height of 2.913m.The best diameter growth was shown by treatment A4(500gr/plant) with average 3.840 cm and the lowest was shown by treatment A0(100gr/plant) with average 2.933cm. These results indicate that increasing fertilizer dosage had no effect on height growth of young plants of ebony(D. pilosanthera) at 2 years old in Arboretum of Manado Forestry Research Institute, but had effects ondiameter growth, although not significant between group of treatments.

Propagation of Some Local Fig (Ficus carica L.) Cultivars by Hardwood Cuttings under the Field Conditions in Tunisia.

This research was carried out in Southeast of Tunisia in 2009 and 2010, in order to study the propagation of six (Ficus carica L.) cultivars by using hardwood cuttings under the field conditions. The effect of the cultivars and the type of buds, shoots age, shoots length, and shoots diameter were recorded. Ten cuttings per cultivar and/or cutting types with three replications were planted in rooting unit. Percentage of root emergence and six morphological parameters of young fig plants were measured. Results showed that the responses of cuttings as fig nursery plants presented a high variability among the five cultivars. The most widely varied characters were % root emergence (RE) and cumulative growth of young plant (CG). The first one ranged from 10% to 90%, the second varied within 32 and 112 cm. Concerning the ‘‘BITHER” cultivar, 6 cutting types with different age, length, and diameter were evaluated. Results showed a great variation in % of root emergence (0–90%), length of nursery plant (3–77 cm), and number of roots/nursery plant (0–29 roots). The present research showed that the hardwood cutting of local fig cultivars can be propagated under field conditions in Southeast of Tunisia.

The remodeling of seedling development in response to long-term magnesium toxicity and regulation by ABA-DELLA signaling in Arabidopsis.

Little information is available about signaling response to magnesium toxicity (MgT) in plants. This study presents the first evidence that abscisic acid (ABA) and DELLA proteins participate in signaling response to long-term MgT in Arabidopsis thaliana (Landsberg erecta). Morphological, physiological, and molecular characteristics of a wild-type and two Arabidopsis mutants, ABA-insensitive mutant abi1-1 and constitutive elevated GA response mutant quadruple-DELLA (DELLA-Q: gai-t6 rga-t2 rgl1-1 rgl2-1) were monitored under MgT and normal magnesium conditions. Two weeks of MgT treatment strongly influenced the growth of young plants, but growth inhibition of the DELLA-Q and abi1-1 mutants was less than that of the wild-type plants. Exogenous ABA further inhibited the growth of the DELLA-Q mutants, similar to that of the wild-type. Both ABA and MgT also promoted DELLA protein RGA accumulation in the nuclei. Transcriptional analysis supported these results and revealed that a complex signaling network has responded to MgT in Arabidopsis. DELLA enhancement, which depends on ABI1, contributed to the remodeling growth and development of young seedlings.

Influence of magnetic field on germination, growth and production of tomato

In the study with tomatoes, there was ivestigated the impact of extremely low frequency electromagnetic fields on seed germination of tomato (Solanum lycopersicum L.) after treatment before sowing, as well as the growth of young plants that were exposed to low frequency electromagnetic field before planting in the field when growing transplants under cover. In the experiments conducted in two consecutive years (2012 and 2013), we followed the length of seed germination period of tomato variety „Pavlína", growth of young plants expressed in plant height and root length, and the fruit size. Magnetization of seeds and young plants was carried out in laboratory conditions, plant growth was evaluated under cover prior to planting, and fruit traits were followed in field conditions where plants were grown on experimental plots (80.0 m2). The plants were grown in accordance with the standards of an agricultural practice for tomato. At the generative phase, the fruits were collected at regular intervals, and their number and weight were evaluated. Low frequency electromagnetic fields acting at the three inductance levels (20, 40 and 60 mT) and exposure of 20 minutes a day with frequency of 50 Hz, significantly positively influenced the germination, plant growth and fruit size of the studied tomato variety.

Contrasting physiological responses to high salinity between two varieties of corn ‘Lluteño’ (salt tolerant) and ‘Jubilee’ (salt sensitive)

'Lluteno' is the only one corn capable to prosper in the Valley of Lluta under saline conditions (EC = 9.1 dS m-1). This cultivar has been little studied and there is no current information about its growth and about the possible mechanisms involved in its tolerance to salts. The aim of this research was to compare the growth of young plants of corn ( Zea mays L.) 'Lluteno' to that of the bred 'Jubilee', both grown under different salt concentrations, to characterize the absorption and distribution of Na+ and other nutrients in the plant and to evaluate the effect of the saline conditions in the osmotic adjustment in both cultivars. The plants of 21 d old were subjected for 15 d to two saline treatments: 50 and 100 mM NaCl. The accumulation of DM was reduced from 5.12 to 1.80 g plant-1 in 'Jubilee' and 5.53 to 4.12 g plant-1 in 'Lluteno' (P ≤ 0.05). 'Lluteno' showed to be more tolerant to salt stress that 'Jubilee' by greatest accumulation of biomass under saline conditions, it was associated with a lower accumulation of Na+, steadiness of K+ and Ca2+ content and accumulation of osmolytes in leaves. The latter affecting positively the maintenance of relative water content and the osmotic adjustment of this cultivar in the leaves.

Effect of lead contamination of maize seed on its biological properties

Effect of treatment of seed with various lead concentrations (0, 10-5, 10-4, 10-3, and 10-2 mol/dm3) on accumulation and distribution of lead (Pb) in seedling, seed germination, seedling growth, and mobilization of mineral matter during seed germination was investigated. Content of Pb in the root and the shoot indicates that seeds imbibed in solutions of various Pb concentrations took up Pb intensively. Content of Pb in the root and the shoot increased with increase of Pb concentration and it was much larger in the root than in the shoot. Contrary to this, the accumulation coefficient was greater in the shoot than in the root. Treatment of seed with Pb did not significantly affect its biological properties. Increase of Pb concentration decreased germination ability, germination energy, and percentage of typical seedlings, while increasing the number of atypical seedlings and non-germinated seeds. Contamination of seed by Pb did not affect the dry matter mass and the growth of young plants shoots, while the length of the primary root, the mesocotyl root as well as the root mass at the highest Pb concentration, significantly decreased. Translocation of mobilized mineral matter from the seed during germination and growth of young plants into the root and shoot was specific, depending on elements. Only the implementation of the highest implemented Pb concentration affected mobilization and translocation of some elements. Based on the obtained results, it can be concluded that maize is characterized by significant tolerance to Pb contamination during seed germination and growth of seedlings.

Summer Dormancy in Phalaris aquatica L., the Influence of Season of Sowing and Summer Moisture Regime on Two Contrasting Cultivars

AbstractA series of trials to increase understanding of the summer dormancy trait in Phalaris aquatica was conducted. Autumn‐sown and younger, spring‐sown plants of two cultivars (cvv), known to contrast in expression of summer dormancy, were established and then tested over the following summer under three moisture regimes: long drought; drought + mid‐summer storm; or full irrigation. The autumn‐sown plants of cv. Atlas PG expressed substantial but incomplete summer dormancy under all moisture regimes and exhibited the characteristic responses including significant growth reduction and herbage senescence. The summer‐dormant cv. Atlas PG used 31 mm less soil water over the summer and also began to rehydrate its leaf bases from conserved soil water before the drought broke. The non‐dormant cv. Australian grew whenever moisture was applied and also responded to the mid‐summer storm with a decline in dehydrin expression in leaf bases, whereas no decline occurred in Atlas PG, presumably because it remained dormant. The irrigated, younger, spring‐sown swards of cv. Atlas PG had restrained growth and produced only about 37 % of the herbage of cv. Australian. Drought reduced activity and growth of young plants of both cultivars but while Australian regrew in response to the storm, cv. Atlas PG, grew much less (59 % of Australian) indicating that dormancy, although only partially expressed after spring sowing, was reinforced by summer drought. Australian used more soil water over summer than Atlas PG, and it is suggested that this is why cv Australian is limited to the higher rainfall zones of south‐eastern Australia, particularly where soil water holding capacity is limited.

The response of different almond genotypes to moderate and severe water stress in order to screen for drought tolerance

In order to screen almond genotypes for drought tolerance, three different irrigation levels including moderate and severe stress ( Ψs = −1.2 and −1.8 MPa respectively) and a control treatment ( Ψs = −0.33 MPa) were applied for five weeks to six different cultivated almond seedlings. A factorial experiment was conducted with a RCBD which included 3 irrigations factors, 6 genotype factors and 3 replications. Seeds were prepared from controlled pollination of the bagged trees (after emasculation and flower isolation using isolator packets in the previous year). Genotypes included: homozygote sweet (Butte), heterozygote sweet (SH12, SH18, SH21 and White) and homozygote Bitter (Bitter Genotype). Leaf and root morphological and physiological traits including; midday relative water content, midday leaf (xylem) water potential, shoot dry weight and growth, total leaf area, leaf size, total leaf dry weight, specific leaf area, leaf greenness (SPAD), stomatal size and density, root and leaf nitrogen content and chlorophyll fluorescence were measured throughout the study. Results showed the six genotypes had different reactions to water stress but all genotypes showed an ability to tolerate the moderate and severe stresses and they showed different degrees of response time to drought stress. Almond seedling leaves could tolerate Ψ w between −3 and −4 MPa in short periods. Water availability did not significantly affect stomatal density and size of young almond plants. The analysis of leaf anatomical traits and water relations showed the different strategies for almond genotypes under water stress conditions. Although almond seedlings even in severe stress kept their leaves, they showed a reduction in size to compensate for the stress effects. All genotypes managed to recover from moderate stress so Ψ w = −1.2 could be tolerated well by almond seedlings but Ψ w = −1.8 limited young plant growth. Leaf greenness, leaf size, shoot growth, shoot DW, TLDW and stomatal density were not good markers for drought resistance in almond seedlings. Root DW/LA, lower stomatal size and lower SLA might be related to drought resistance in cultivated almonds. Butte had the least resistance and White showed better performance during water stress while other genotypes were intermediate. Bitter seedlings showed no superiority in comparison with other genotypes under water stress conditions except for better germination and greater root DW which might make them suitable as rootstocks under irrigation conditions.

Nitrogen nutrition of young triticale plants grown under aluminium stress

stress Ana Maria Domingues1, 2 1Tropical Research Institute, Department of Natural Sciences / Instituto de Investigacao Cientifica Tropical, Departamento de Ciencias Naturais Tapada da Ajuda – PAIAT, 3 rd floor/ 3o piso Apartado 3014, 1301-901 Lisboa Codex PORTUGAL 2Centro de Estudos da Macaronesia / Center for Macaronesian Studies, University of Madeira, Campus Penteada, 9000-390 Funchal - PORTUGAL E-mail: dam.portugal@hotmail.com ABSTRACT Triticale has proven to be a tolerant crop in many places around the globe, under extreme climatic and edaphic conditions, particularly in Al-toxic soils. To suffice the growing food demand of the world population, one of the most important goal is the sustainable increase of cereal production avoiding the anthropogenic pollution, often air and groundwater contamination by volatilization and leaching of N compounds. The effects of enhanced ammonia proportion in relation to nitrate nutrition in hydroponics, with or without Al, were investigated on the short-term growth of triticale plants. Three days old plants of the Al-tolerant genotype TTE 9203 were submitted to 0 or 370 mM Al and received different NO3-/ NH4+ ratios with the four proportions 15:1, 8:1, 3:1 and 1:1 (with fixed total N concentration at 3.2 mM in all treatments). In relation to the corresponding control solutions, 370 mM Al induced important decreases in root length, ranging from 75.3 % to 47.3 %, reductions in fresh weight from 80 % to 60 % in roots, and from 89 % to 71 % in shoots, depending on the NO3-/ NH4+ ratio. A decrease in NO3- net uptake was shown by plants in the presence of Al. The most detrimental Al effect for young plant growth in nutrient solutions was observed with the 15:1 NO3-/ NH4+ ratio, which induced the highest reductions of length of the main root (52.7 % reduction relative to control) and of root biomass fresh weight (40.6 %) in four days of treatment. By the contrary, the plants grown in the 8:1 ratio solution with Al suffered the smallest reductions of root length (24.7 % in 370 mM Al treatment relative to control) and of root biomass fresh weight (20.3 %). Taken together the results indicate that NH4+ can alleviate Al toxicity in triticale and point out the ideal NO3-/ NH4+ proportion of 8:1 as the best for these young plants growth and N use efficiency, under acidic and Al toxic condition. Some economical and ecological advantages of NH4+- N sources use in plant fertilization are discussed.

Comparative physiological, ultrastructural and proteomic analyses reveal sexual differences in the responses of Populus cathayana under drought stress

Drought is a major abiotic stress, limiting the survival and growth of young plants. However, little is known about sex-dependent responses to drought at the proteome level. In this study, we carried out investigations on comparative proteomics, combined with physiological and organelle structure analyses, in males and females of Populus cathayana Rehd. Three-month-old poplar cuttings were treated at 30% of field capacity and at 100% field capacity as a control in a greenhouse for 40 days. Drought greatly inhibited plant growth, damaged the photosynthetic system and destructed the structures of chloroplasts, mitochondria and cellular membranes. However, males suffered less from the adverse effects of drought than did females. Using 2-DE, 563 spots were detected, of which 64 spots displayed significant drought effect and 44 spots displayed a significant sex by drought interaction effect. The results suggest that the different responses to drought stress detected between the sexes have a close relationship to the changes in the expression of sex-dependent proteins, including, e.g. photosynthesis-related proteins, homeostasis-related proteins and stress response proteins. These proteins could contribute to a physiological advantage under drought, giving potential clues for understanding sexual differences in the performance of plants in different environments.

Resistência parcial à brusone de genótipos de trigo comum e sintético nos estádios de planta jovem e de planta adulta

A brusone do trigo, causada pelo fungo Pyricularia grisea foi relatada pela primeira vez no Brasil, no estado do Paraná, em 1985. Desde então, busca-se, dentre o germoplasma disponível no País, cultivares resistentes à doença. O objetivo deste trabalho foi determinar o grau de resistência parcial de genótipos de trigo comum e de trigo sintético nos estádios de planta jovem e de planta adulta. Para a avaliação na fase de planta jovem foram escolhidos 70 genótipos de trigo, os quais foram submetidos à inoculação com 18 isolados de P. grisea. Dos 70 genótipos, 12 foram selecionados para a avaliação em planta adulta. Entre os genótipos resistentes em planta jovem destacaram-se BRS 229, BRS 179, CNT 8, BRS 120 e BRS Buriti. No estádio de planta adulta, os genótipos CNT 8, NE 20156-B, PF 844001, PF 964009 e PF 804002 foram aqueles que apresentaram menor severidade da doença.