INFLUENCE OF FOLIAR FERTILIZATION AND GROWTH REGULATOR ON MILK THISTLE SEED YIELD AND QUALITY

The effects of foliar fertilization and a growth regulator 5-tert-butyl-N-m-tolylpyrazine-2-carboxamide (MD148/II) on the growth, seed yield, and silymarin content of milk thistle (Silybum marianum Gaertn.) plants were evaluated. The study was conducted over two years at an experimental field on a slightly acid-leached cinnamonic meadow soil. The MD148/II was applied in the beginning of milk thistle flowering stage. Foliar fertilizer was applied at different plant developmental stages with different proportions of nitrogen (N), phosphorus (P), and potassium (K). Treatments with foliar fertilizer and MD148/II resulted in improvement of plant biomass, number of plant lateral shoots, flowering rate, and seed yield and the content of some active substances in milk thistle seeds. A reduction of high molecular fatty acids was observed. The increase of seed yield was a result of the flower head setting enhancement. Therefore the combined treatment of foliar fertilizer and MD148/II was efficient in elicitation milk thistle production under field conditions.     

Grain Yield and Active Substances of Milk Thistle as Affected by Soil Salinity

The ripe seeds of milk thistle (Silybum marianum L. Gaertn) contain active substances of flavonoides that are important in the pharmaceutical industry. Evidence showed that stress conditions such as salinity can affect growth and development of plants, including active substances of some medicinal plants. Silymarin and silybin are important active materials of milk thistle whose concentrations correspond to some degree of plant stress. To test for this relationship, a pot experiment was conducted using a completely randomized design with seven level of salinities (0.35, 1, 3, 6, 9, 12, and 15 dS/m) for two genotypes, Ahwaz wild type and cultivated German origin (Royston). At the harvest, the results have showed that both genotypes grow satisfactorily and had a normal size in soils up to salinity of 9 dS/m, compared to the control plants. However, growth parameters such as plant height, number of leaves per plant, number of capitula per plant, main shoot capitulum's diameter, and seed yield and yield components per plant was reduced with salinity greater than 9 dS/m in both genotypes. However, concentrations of active substances (silymarin and silybin) in seeds significantly increased compared to the control plants. Results from the high‐performance liquid chromatography (HPLC) analysis indicated that the amount of silybin was approximately four times greater in plants cultivated under a salinity of 15 dS/m than in the plants grown under nonsaline conditions. Our results suggested that both types of milk thistle survive under salinity as high as 15 dS/m levels and produced seeds with rich in active substances.     

Biochar Application and Drought Stress Effects on Physiological Characteristics of Silybum marianum

Soil amending with biochar has been viewed as a sustainable way to improve soil moisture holding capacity. The potential of biochar application to improve water status of crops under drought stress has not been extensively evaluated. In this study, we evaluated the impact of biochar application (0%, 1%, and 2% w/w soil) on some important physiological traits of milk thistle (Silybum marianum L. Gaertn) under moderate and severe drought stress conditions in a controlled environment. Although, the application of biochar at the higher rate slightly improved soil moisture holding capacity, the magnitude of its effect was not sufficient to influence plant performance under drought stress. To get the positive effects of biochar application on milk thistle performance under drought stress, application with higher rates is probably necessary.     

Diversity in cowpea (<Emphasis Type="Italic">Vigna unguiculata</Emphasis> (L.) Walp.) local populations from Greece

Cowpea cultivation in many countries around the Mediterranean Basin depends on a number of locally adapted populations conserved on-farm at a small scale, rather than on the use of modern varieties. Documentation, characterization and exploitation of traditional local populations could contribute to their conservation and utilization as sources of desirable characteristics. Therefore, a study was conducted to (a) characterize, (b) assess diversity and (c) classify 23 on-farm conserved local cowpea populations based on 32 agro-morphological traits. Investigations on diversity of characteristics related to seed yield, mineral and seed crude protein content as well as on correlations among them were carried out. A relatively high phenotypic diversity was observed. In particular, a high level of within population diversity was found (\( \bar{H}s \) = 0.34) exceeding that among populations’ diversity (Gst = 0.27). Principal component analysis classified the majority of local populations into two groups (mainly according to populations’ seed coat color and eye color), further divided into six subgroups regardless of the populations’ geographical origin. Significant differences were also observed among the populations studied for potassium and calcium, as well as for their seed crude protein content which ranged from 22.14 to 28.37 %. The results show appreciable levels of intra- and inter-phenotypic diversity in on-farm conserved cowpea populations, which indicates the existence of a valuable gene pool for future exploitation in breeding programs.     

Horticultural practices and varietal diversity of chili pepper (<Emphasis Type="Italic">Capsicum annuum</Emphasis> L.) in Central and Northern Benin

Chili peppers play a significant role in the world diet and can contribute to the improvement of horticultural producers’ incomes. In Benin, chili pepper production is hampered by many challenges that need to be characterized, prioritized and addressed. Moreover, the existing diversity, as well as the agronomic potential, of the varieties being cultivated in Benin is still not well understood. In order to define the scientific basis for the improvement of chili pepper production and the preservation of its diversity, one hundred villages were randomly selected and surveyed in Northern and Central Benin by using participatory research appraisal tools and techniques. Twelve production constraints were identified, of which low productivity (19 %), soil infertility (18.5 %), drought (18.3 %), pests and disease susceptibility (17.9 %), early fall of plant organs (15 %) appear as the most important. In terms of diversity, 77 chili pepper varieties (40 from the frutescens group, 24 from the annuum group and 13 from the chinense group) including 72 local and five introduced varieties (Tataché, Yèyèkouka, Yèyèkouokourè, Côte d’ivoire and MC) were found. The number of varieties varies from three to seven (four on average) per village and from one to five by household. The proportion of loss of diversity per village varies from 0 to 75 % with an average of 26.61 %. Susceptibility to pests and diseases (37.1 % of responses), early fall of plant organs (11.6 % of responses) and susceptibility to drought (8.5 %), were the most important reasons given in attempts to explain the loss of diversity. Farmers’ varietal preference criteria are essentially agronomic (90.4 % of responses). The participative agronomic evaluation revealed that the varieties of frutescens group are significantly higher with respect to the evaluated variables, but they are less appreciated by the consumers.     

Salinity and Temperature Effects on Seed Germination of Milk Thistle

Abstract

Milk thistle [Silybum marianum (L.) Gaertn] is an annual plant belonging to the Asteraceae family whose ripe seeds contain flavonoid substances, which are important in the modern pharmaceutical industry. Seed germination is a major factor limiting the establishment of plants under saline conditions. The effect of salinity and temperatures on germination and seedling establishment was studied in two genotypes of milk thistle, an Iranian wild type and German (Royston) type in the laboratory and in the field. Experiments were done with seven salt concentrations [0.1 (control), 1, 3, 6, 9, 12, and 15 dS/m] and three temperatures (15, 25, and 35°C). There were three replications for each treatment, and the experiment was run three times. The results showed that the percentage of germination and the number of normal seedlings at different salt treatment at 15°C were higher than at 25 or 35°C. The mean time to 50% germination was least at this temperature for both genotypes. Results suggested all germination indices and seedling emergence (50%) were achieved at levels up to 9 dS/m salinity at 15°C. Also, seeds at a salinity of 9–15 dS/m will germinate and up to 25% of the control nonstress treatment could emerge at the low temperature of 15°C.     

Morphological and genetic diversity of shea tree (<Emphasis Type="Italic">Vitellaria paradoxa</Emphasis>) in the savannah regions of Ghana

Vitellaria paradoxa C. F. Gaertn., commonly known as shea tree or Vitellaria, is ranked the most important tree species of the savannah regions in the most African countries due to its ecological and economic importance for livelihoods and national economies. However, the savannah regions are the most vulnerable areas to the global climate change. Moreover, the Vitellaria populations on farmlands are threatened by the dominance of old trees with low or lack of regeneration. In this study both morphological and genetic diversity were assessed using several phenotypic traits and 10 microsatellite markers, respectively, to assess the impact of land use and agro-ecozone types on Vitellaria in Ghana. The land use types were forests and farmlands, and the agro-ecozone types included the Transitional, Guinea, and Sudan savannah zones. The mean values of morphological traits, such as diameter at breast height (DBH) and canopy diameter (CD), were statistically different between forest (DBH = 22.20, CD = 5.37) and farmland (DBH = 39.85 CD = 7.49) populations (P < 0.00001). The Sudan savannah zone with mean petiole length of 4.96 cm showed significant difference from the other zones, likely as a result of adaptation to drier climate conditions. Genetic data analysis was based on 10 microsatellite markers and revealed high genetic diversity of Vitellaria in Ghana: mean expected heterozygosity, H _e was 0.667, and allelic richness, measured as number of effective alleles A _e , was 4.066. Both farmlands and forests were very diverse indicating lack of negative influence of farmer’s selection on genetic diversity. Fixation index was positive for all populations (mean F _IS = 0.136) with farmlands recording relatively higher values than forests in all ecological zone types studied, probably indicating less gene flow in the farmlands. Moderate differentiation (F′ _ST = 0.113) was comparable to other similar tree species. Both land use and ecological zone types influenced genetic differentiation of Vitellaria at varying levels. The species was spatially structured across three ecozones and following climatic gradient. The forest reserves are used in situ conservation for Vitellaria in Ghana. High diversity observed in the most arid zones provides opportunity to find and use appropriate plant materials for breeding climate change resilient trees.     

<Emphasis Type="Italic">Trichoderma</Emphasis> improves the growth of <Emphasis Type="Italic">Leymus chinensis</Emphasis>

Bio-fertilizer application has been proposed as a strategy for enhancing soil fertility, regulating soil microflora composition, and improving crop yields, and it has been widely applied in the agricultural yields. However, the application of bio-fertilizer in grassland has been poorly studied. We conducted in situ and pot experiments to investigate the practical effects of different fertilization regimes on Leymus chinensis growth, with a focus on the potential microecological mechanisms underlying the responses of soil microbial composition. L. chinensis biomass was significantly (P?<?0.05) increased by treatment with 6000 kg ha^?1 of Trichoderma bio-fertilizer compared with other treatments. We found a positive (R² =?0.6274, P <?0.001) correlation between bacterial alpha diversity and L. chinensis biomass. Hierarchical cluster analysis and nonmetric multidimensional scaling (NMDS) revealed that soil bacterial and fungal community compositions were all separated according to the fertilization regime used. The relative abundance of the most beneficial genera in bio-fertilizer (BOF) (6000 kg ha^?1Trichoderma bio-fertilizer) was significantly higher than in organic fertilizer (OF) (6000 kg ha^?1 organic fertilizer) or in CK (non-amend fertilizer), there the potential pathogenic genera were reduced. There were significant negative (P?<?0.05) correlations between L. chinensis biomass and the relative abundance of several potential pathogenic genera. However, the relative abundance of most beneficial genera were significantly (P?<?0.05) positively correlated with L. chinensis biomass. Soil properties had different effects on these beneficial and on these pathogenic genera, further influencing L. chinensis biomass.     

Genetic diversity of dihydrochalcone content in <Emphasis Type="Italic">Malus</Emphasis> germplasm

Dihydrochalcones, beneficial phenolic compounds, are abundant in Malus Mill. species, particularly in vegetative tissues and seeds. Phloridzin (phloretin 2′-O-glucoside) is the primary dihydrochalcone in most Malus species including cultivated apple, Malus?×?domestica Borkh. A few species contain sieboldin (3-hydroxyphloretin 4′-O-glucoside) or trilobatin (phloretin 4′-O-glucoside) in place of phloridzin, and interspecific hybrids may contain combinations of phloridzin, sieboldin, and trilobatin. Proposed health benefits of phloridzin include anti-cancer, antioxidant, and anti-diabetic properties, suggesting the potential to breed apples for nutritional improvement. Sieboldin and trilobatin are being investigated for nutritional value and unique chemical properties. Although some of the biosynthetic steps of dihydrochalcones are known, little is known about the extent of variation within Malus germplasm. This research explores the genetic diversity of leaf dihydrochalcone content and composition in Malus germplasm. Dihydrochalcone content was measured using high performance liquid chromatography (HPLC) from leaf samples of 377 accessions, representing 50 species and interspecific hybrids from the USDA-Agricultural Research Service (ARS) National Plant Germplasm System Malus collection. Within the accessions sampled, 284 accessions contained phloridzin as the primary dihydrochalcone, one had only trilobatin, two had phloridzin and trilobatin, 36 had sieboldin and trilobatin, and 54 had all three. Leaf phloridzin content ranged from 17.3 to 113.7 mg/g with a heritability of 0.76 across all accessions. Beyond the potential of dihydrochalcones for breeding purposes, dihydrochalcone composition may be indicative of hybridization or species misclassification.     

Distribution Characters of Absorption Nitrogen in Oilseed Rape (Brassica Napus L.) at Different Growth Stages

Two winter oilseed rape varieties grown in sand culture were labeled with ¹⁵Nitrogen (¹⁵N) at different growth stages to show the route of nitrogen (N) absorption, distribution, and transfer in oilseed rape (Brassica napus L.). Averaged over the two varieties, 84% of the N absorbed at the seedling stage, and 67% of the N absorbed at the stem elongation stage were distributed into the leaves. Of the N absorbed at flowering stage, 43% was distributed into the leaves and 36% into stems. However, 42.4% of the N absorbed at siliquing stage was directly found into the silique. The proportion of the N redistributed from vegetative organs into reproductive organs was 34%, 44%, 41%, and 32%, at seedling, stem elongation, flowering, and siliquing stages, respectively. The amounts of N transferred were 203, 326, 218, and 82 mg per plant, respectively. This corresponded to 65% of the total in the grain. The proportions of N lost after absorption were 24%, 11%, 12%, and 7% at the four growth stages, respectively. The amounts lost were 142, 79, 43, and 16 mg per plant, respectively. N absorbed at early growth stages in oilseed rape was mainly distributed to the leaves first, and then redistributed to the reproductive organs later. This route provided most of the N for the reproductive organs.     

Carbon sequestration potential of hydrothermal carbonization char (hydrochar) in two contrasting soils; results of a 1-year field study

Soil amendment with hydrochar produced by hydrothermal carbonization of biomass is suggested as a simple, cheap, and effective method for increasing soil C. We traced C derived from corn silage hydrochar (δ¹³C of ?13?‰) added to “coarse” and “fine” textured soils (δ¹³C of ?27?‰ for native soil C (SOC)) over two cropping seasons. Respiration rates increased in both soils (p?<?0.001) following hydrochar addition, and most of this extra respiration was derived from hydrochar C. Dissolved losses accounted for ~5 % of added hydrochar C (p?<?0.001). After 1 year, 33?±?8 % of the added hydrochar C was lost from both soils. Decomposition rates for the roughly two thirds of hydrochar that remained were very low, with half-life for less estimated at 19 years. In addition, hydrochar-amended soils preserved 15?±?4 % more native SOC compared to controls (negative priming). Hydrochar negatively affected plant height (p?<?0.01) and biomass (p?<?0.05) in the first but not the second crop grown on both soils. Our results confirm previous laboratory studies showing that initially, hydrochar decomposes rapidly and limits plant growth. However, the negative priming effect and persistence of added hydrochar C after 1 year highlight its soil C sequestration potential, at least on decadal timescales.     

A Comparative Study on Removal Efficiency of Cr(VI) in Aqueous Solution by <Emphasis Type="Italic">Fusarium</Emphasis> sp. and <Emphasis Type="Italic">Myrothecium</Emphasis> sp.

Environmental pollution with chromium is due to residues of several industrial processes. Bioremediation is an alternative actually considered to remove Cr (VI) from the environment, using adapted organisms that grow in contaminated places. Have been conducted studies with fungi mechanisms of interaction with chromium, most of which have focused on processes biosorption, characterized it by passive binding of metal components of the cell surface, and bioaccumulation, wherein the metal entry to cells occurs with energy expenditure. The paper presents the results of studies carried out on sorption of chromium (VI) ions from aqueous solutions by Fusarium sp. and Myrothecium sp. Both biomasses have the ability to take up hexavalent chromium during the stationary phase of growth and as well inactive conditions. Fusarium sp. showed 26% of biosorption with active biomass and 64% in inactive biomass; meanwhile, Myrothecium sp. obtained 97 and 82%, respectively. Both fungi showed adjust to pseudo-second-order model in active (Fusarium sp. R ² = 0.99; Myrothecium sp. R ² = 0.96) and inactive biomass assay (Fusarium sp. R ² = 0.99; Myrothecium sp. R ² = 0.99). The data of the active biomass test also confirmed to the intraparticle diffusion model (Fusarium sp. R ² = 0.98; Myrothecium sp. R ² = 0.93). The results obtained through this investigation indicate the possibility of treating waste effluents containing hexavalent chromium using Fusarium sp. and Myrothecium sp.     

Assessment of artificial selection in maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) and Asian rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) using QTL data

Maize (Zea mays L.) and Asian rice (Oryza sativa L.), two most important cereals for human nutrition, have undergone strong artificial selection during a long period of time. Currently, a number of genes with stronger signals of selection have been identified through combining genomic and population genetic approach, but research on artificial selection of maize and Asian rice is scarcely done from the perspective of phenotypic difference of a number of agronomic traits. In this study, such an investigation was carried out on the basis of 179 published studies about phenotypic quantitative trait locus (QTL) mapping of Zea and Oryza species via QTL sign test. At the overall level, the proportions of antagonistic QTLs of Zea and Oryza species were 0.2446 and 0.2382 respectively, deviating significantly from neutrality. It indicated that these two genera have undergone similar selection strength during their evolutionary process. A previous study showed that 4 traits undergoing the directional selection during domestication were identified in Asian rice via QTL sign test, and 16 individual traits in Asian rice and 38 ones in maize that newly detected in this study deviated significantly from neutrality as well, demonstrating the dominant influence of artificial selection on them. Moreover, analysis of different categories of cross type including O. sativa × Oryza rufipogon (perennial and annual forms) crosses, maize × teosinte (Zea mays subsp. parviglumis) crosses, O. sativa × O. sativa crosses, and maize × maize crosses showed that their proportions of antagonistic QTLs were 0.1869, 0.1467, 0.2649, and 0.2618 respectively. These results revealed that selection strength of domestication is significantly stronger than that of modern genetic improvement. However, interestingly, the proportion of antagonistic QTLs (0.1591) in maize × maize with long-term selection was very similar to that (0.1467) in the maize × teosinte (Zea mays subsp. parviglumis) crosses. It suggested that some favorable traits could be cultivated within a few decades if we carry out strong selection. In addition, the proportions of antagonistic QTLs of the widely cultivated hybrids of rice (Minghui 63 × Zhenshan 97) and maize (Zheng 58 × Chang 7-2) in China were 0.309 and 0.3472 respectively. It suggested that selection during modern genetic improvement has significantly acted on them.     

Altered precipitation seasonality impacts the dominant fungal but rare bacterial taxa in subtropical forest soils

How soil microbial communities respond to precipitation seasonality change remains poorly understood, particularly for warm-humid forest ecosystems experiencing clear dry-wet cycles. We conducted a field precipitation manipulation experiment in a subtropical forest to explore the impacts of reducing dry-season rainfall but increasing wet-season rainfall on soil microbial community composition and enzyme activities. A 67% reduction of throughfall during the dry season decreased soil water content (SWC) by 17–24% (P < 0.05), while the addition of water during the wet season had limited impacts on SWC. The seasonal precipitation redistribution had no significant effect on the microbial biomass and enzyme activities, as well as on the community composition measured with phospholipid fatty acids (PLFAs). However, the amplicon sequencing revealed differentiated impacts on bacterial and fungal communities. The dry-season throughfall reduction increased the relative abundance of rare bacterial phyla (Gemmatimonadetes, Armatimonadetes, and Baoacteriodetes) that together accounted for only 1.5% of the total bacterial abundance by 15.8, 40, and 24% (P < 0.05), respectively. This treatment also altered the relative abundance of the two dominant fungal phyla (Basidiomycota and Ascomycota) that together accounted for 72.4% of the total fungal abundance. It increased the relative abundance of Basidiomycota by 27.4% while reduced that of Ascomycota by 32.6% (P < 0.05). Our results indicate that changes in precipitation seasonality can affect soil microbial community composition at lower taxon levels. The lack of community-level responses may be ascribed to the compositional adjustment among taxonomic groups and the confounding effects of other soil physicochemical variables such as temperature and substrate availability.     

The impact of modern plant breeding on dominant Chinese wheat cultivars (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) revealed by SSR and functional markers

The modern plant breeding is generally considered to be a practice that leads to a narrowing in genetic diversity of crops. The objective of the present study was to assess whether this practice has led to the reduction of genetic diversity in modern Chinese wheat cultivars. A set of 80 dominant Chinese wheat cultivars released from 1942 to 2011 was used to describe the genetic diversity based on 137 simple sequence repeat (SSR) and 52 functional markers. Several important properties about the genetic diversity were revealed. First, relative low genetic diversity level was detected on a genome-wide scale. A total of 752 alleles were detected with a range from 1 to 15, and the mean polymorphic information content value was 0.53 with a range from 0.00 to 0.87. Second, the genetic diversity significantly decreased from 2001 to 2011 at the genome-wide level. More importantly, significant differences of genetic diversity among the three different genomes were observed by the analysis of variance (ANOVA). The three genomes had clearly different changing trends over time: the A genome displayed a decreasing trend (regression coefficient (b) = ?0.01); in contrast, the other two genomes, B and D, showed the increasing trends (b = 0.01 for the B genome, P = 0.05; b = 0.01 for the D genome, P = 0.05). Third, the analysis of qualitative variations in allelic composition over time indicated that, the more recent the cultivars were, the more similar they were to each other. Finally, the frequencies of favorable alleles related to important agronomic traits had been increasing over time or maintained high frequencies in all seven temporal groups. These findings indicate that modern wheat breeding results in not only a qualitative, but also a quantitative change in genetic diversity in the dominant Chinese wheat cultivars. A special attention should be paid to broaden the genetic base in the A genome.     

Exogenously Applied Citric Acid Enhances Antioxidant Defense and Phytoextraction of Cadmium by Willows (<Emphasis Type="Italic">Salix</Emphasis> Spp.)

The effect of exogenously applied citric acid (CA) on phytoextraction and antioxidant defense was analyzed using willow species (Salix viminalis, S. alba, and S. matsudana) grown in soil contaminated with cadmium (Cd). Citric acid has been used as a chelating agent for the purpose of accelerating the solubility of Cd in soil and enhancing the phytoextraction of selected plants. Willows were exposed to 6 mg/kg of Cd, following the same with citric acid (20 mM/kg soil). Results revealed a positive effect of citric acid in mobilization of accumulated Cd from roots to shoots and leaves. The addition of citric acid alleviated Cd toxicity by helping plants to overcome oxidative stress, through CA’s chelating properties and the increased activity of antioxidant enzymes. Different protection strategies were evident through modification of activities of antioxidant enzymes such as catalase (CAT), ascorbate-peroxidase (APx), and guaiacol peroxidase (GPx) in young versus mature leaves in plants exposed to Cd. Furthermore, results revealed that addition of citric acid may be beneficial in the reduction of the negative effect of Cd stress on photosynthesis. The efficiency of coupling phytoextraction with the chelating agents represents a good strategy for decreasing damages caused by cadmium and has good potential in decontamination of a polluted environment.     

Effects of red mud addition on cadmium accumulation in cole (<Emphasis Type="Italic">Brassica campestris</Emphasis> L.) under high fertilization conditions

Purpose

Applications of mineral and organic fertilizer increased soil cadmium (Cd) and could enhance Cd concentrations in edible crops, respectively. Although red mud (RMD) effectively decreased metal bioavailability in soil, the influence of RMD addition on vegetable growth and metal accumulation under high fertilization conditions has rarely been addressed. The aim of this study was to investigate the effects of raw RMD addition on cole growth, quality, and nutrition and Cd accumulation under high fertilization conditions.

Materials and methods

Pot experiments with cole (Brassica campestris L.) were carried out in a greenhouse. Three treatments, CK (with no mineral fertilizer and RMD addition), CT (more than 2.5 times conventional level of mineral fertilizer applied without any RMD), and RM (more than 2.5 times conventional level of mineral fertilizer applied with RMD added at 0.4 % w/w), were established. After 40 days, the cole plants and soils of every replicate of all treatments were sampled. The Cd, biomass, vitamin C (VC), and total nitrogen and phosphorus of the cole plant samples and the Cd, pH, nitrate, and phosphorus of the soil samples were determined.

Results and discussion

In contrast to the CT treatment, RM treatment did not significantly influence the biomass and nitrate concentration of the aboveground cole. However, it significantly reduced the Cd content in cole shoots and its bioaccumulation factors by 30.0 and 28.5 %, respectively. The reduction of bioavailable Cd in soil by RMD sorption and the competition with calcium released from RMD led to low Cd assimilation by root. Finally, less Cd was transported to aboveground plant parts in the RM treatment compared with the CT treatment. RMD addition markedly enhanced the total nitrogen in cole shoots by >16.0 %, and the VC by 20.9 %. The promotion of bacterial abundance and soil enzyme activity by RMD addition and calcium release from RMD generated substantial plant available nitrogen.

Conclusions

With large rate of mineral fertilizer application to the soil, RMD (0.4 %, w/w) addition did not significantly influence the biomass, nitrate, and VC of aboveground cole; however, it significantly reduced the Cd and markedly enhanced the total nitrogen in cole shoots. This study provides valuable information for the safe application of RMD in vegetable production.

     

Maguey (<Emphasis Type="Italic">Agave salmiana</Emphasis>) infructescence morphology and its relationship to yield components

Agaves are long-lived semelparous plants that produce a high number of seeds, in dehiscent capsules, on the apical section of a stalk, up to 5 m long, after 8–25 years. These and other characteristics such as yield and yield components are scarcely evaluated in the plants of the Agave genus. The objective of this study was to quantify the capsules and seeds yield of A. salmiana Otto ex Salm-Dyck plants simultaneously maturing and growing in the same region. Infructescences of three plants simultaneously growing at San Luis Potosí, Mexico, were harvested. On them we evaluated the number of umbels, capsules and seeds (normal and sterile) and their mass per plant. The study was developed on a completely randomized design with each infructescence as an experimental unit. Also, the type distribution of the number and mass of these yield components along the stalk was evaluated with the Chi square test for goodness of fit, the Shapiro–Wilks for normality tests, asymmetry and kurtosis. Data were analyzed with the ANOVA and multiple comparisons by the Tukey test (p?≤?0.05). The number of umbels per plant (17–25), capsule per umbel (2–179) and per plant (554–1990), normal seed per capsule (0–297), normal seeds per plant (30,610–186,209) and sterile seeds per plant (211,059–619,251) widely and significantly varied among infructescences. Biomass of capsules per plant umbel (3–795 g), biomass of sterile and normal seeds per capsule (0.071–1.449 and 0–3.320 g), per umbel (0.34–97.76 and 0.21–185.26 g) and per plant (182–1052 and 334–2069 g) also varied widely. Seed yield was statistically different between plants simultaneously growing and maturing at the same site.     

Nuclear and cytoplasmic contributions from <Emphasis Type="Italic">Erianthus arundinaceus</Emphasis> (Retz.) Jeswiet in a sugarcane hybrid clone confirmed through genomic in situ hybridization and cytoplasmic DNA polymorphism

A hybrid between Erianthus arundinaceus (Retz.) Jeswiet and Saccharum spontaneum L. which are wild related species of sugarcane (Saccharum L., Family Poaceae), was repeatedly crossed as female parent with sugarcane commercial varieties to develop near commercial sugarcane clones. The cytoplasm type of the hybrid derivatives were confirmed to be of E. arundinaceus through the mitochondrial and chloroplast DNA polymorphism of nad 4/3-4 intron segment and psbC–trnS segment, respectively. The E. arundinaceus × S. spontaneum hybrid with somatic chromosome number 2n = 62 was confirmed to have 30 chromosomes from E. arundinaceus through genomic in situ hybridization (GISH). The (E. arundinaceus × S. spontaneum) × sugarcane hybrid (2n = 118) had 24 chromosomes from E. arundinaceus whereas its next generation hybrid with sugarcane (2n = 108) had only 12 Erianthus chromosomes. The commercial sugarcane hybrid Co 15015, which is the third generation hybrid with 2n = 106 was confirmed to have two E. arundinaceus chromosomes through GISH. It is the first report of sugarcane with both alien cytoplasm and chromosome contributions from E. arundinaceus.