Increasing Plant Age Research Articles

Morpho-Anatomical Variations in Sisymbrium irio L. Plants Raised from Seeds Treated with γ Radiation.

This study determines the effect of γ irradiation on seed germination, growth, and morpho-anatomical traits of the Sisymbrium irio L. (London rocket) plant. Seeds irradiated with 2.5, 5, 10, 15, and 20 kGy of γ radiation showed a reduced germination percentage (13.68-56.84%) with reference to the control, showing an inverse relationship with radiation dose. Observations recorded at preflowering, flowering, and postflowering stages of plant growth showed a significant (P < 0.05%) dose-dependent decline in many growth parameters, such as root length, shoot length, shoot dry weight, number of leaves, and pods per plant, due to the radiation effect. However, root dry weight, leaf length, leaf dry weight, number of branches, and number of flowers per plant increased at the lowest dose (2.5 kGy) and then declined steadily with the increasing level of radiation. Likewise, several anatomical features (length of fibers and vessel elements, diameter of vessel elements, proportion of cortex, and vasculature in the stem) showed a consistent decrease with increasing γ irradiation in treated plants compared with the control. However, the pith area and the number of vessels per microscopic field decreased significantly with the lowest radiation dose (2.5 kGy) and then increased gradually with higher doses at each ontogenetic stage. The vulnerability factor in the control as well as treated plants increased with increasing plant age. In treated plants, vulnerability was higher under the effect of low-level radiation than in the control, but it showed an inverse relationship with the increasing level of radiation, thus being the lowest at 20 kGy radiation dose. Mesomorphy also showed an almost similar variation pattern with reference to the radiation dose.

Artificial neural networks as a tool for seasonal forecast of attack intensity of Spodoptera spp. in Bt soybean.

Soybean (Glycine max) is the world's most cultivated legume; currently, most of its varieties are Bt. Spodoptera spp. (Lepidoptera: Noctuidae) are important pests of soybean. An artificial neural network (ANN) is an artificial intelligence tool that can be used in the study of spatiotemporal dynamics of pest populations. Thus, this work aims to determine ANN to identify population regulation factors of Spodoptera spp. and predict its density in Bt soybean. For two years, the density of Spodoptera spp. caterpillars, predators, and parasitoids, climate data, and plant age was evaluated in commercial soybean fields. The selected ANN was the one with the weather data from 25 days before the pest's density evaluation. ANN forecasting and pest densities in soybean fields presented a correlation of 0.863. It was found that higher densities of the pest occurred in dry seasons, with less wind, higher atmospheric pressure and with increasing plant age. Pest density increased with the increase in temperature until this curve reached its maximum value. ANN forecasting and pest densities in soybean fields in different years, seasons, and stages of plant development were similar. Therefore, this ANN is promising to be implemented into integrated pest management programs in soybean fields.

Morphological responses of root hairs to changes in soil and climate depend on plant life form

IntroductionRoot hairs increase the surface area of a plant’s root system that is in contact with the soil, thus facilitating plant water and nutrient uptake. However, little is known about the characteristics of the root hairs of herbaceous and woody plants and their specific response patterns to biotic and abiotic variables from the perspective of resource acquisition strategies in the context of global change.MethodsHere, we analyzed 74 published case studies with 1074 observations of root hair traits to identify patterns of root hair length, density and diameter in relation to soil (e.g., soil pH, nutrient levels), growing environments (e.g., greenhouse, field) and climatic factors (e.g., air temperature), as well as genome size and plant age.ResultsRoot hairs were longer, denser and thicker in woody plants compared with herbaceous plants, and the length and diameter of root hairs in herbaceous plants increased with genome size. With increasing plant age, woody plants had significantly longer and thicker root hairs, while root hair density and diameter declined significantly for herbaceous plants. Soil-cultured plants had longer root hairs than solution-cultured plants. The length and density of root hairs were greater in greenhouse-cultured plants than in field-grown plants, and the latter had thicker root hairs than the former. As soil pH increased, root hair length increased but diameter decreased in woody plants, while root hair density increased in herbaceous plants. Increased soil total nitrogen (N) and potassium (K) significantly increased root hair length, density and diameter in herbaceous plants, while soil total N significantly decreased root hair density in woody plants. Root hair length increased significantly, while root hair density decreased significantly, with higher mean annual temperature and greater precipitation seasonality, while the opposite pattern was true for a wider annual temperature range.DiscussionOur findings emphasize the life-form-specific responses of root hairs to soil and climatic variables. These findings will help deepen our understanding of resource acquisition strategies and their mechanisms in different plant forms under global climate change.

Identifying Plant Age to Determine Production Trend of Oil Palm Fresh Fruit Bunches

The productivity management of oil palm plantations is carried out by analyzing various influencing factors, but the growing conditions of oil palms are one of the causes of fluctuations in oil palm production. This paper aims to identify post-harvest increases in oil palm productivity. Productivity depends on the number of clusters and the weight of fresh fruit bunches (FFB) produced yearly. The methods of this study were conducted using a targeted sampling technique using available production data for plant time points from 4 to 13 years of age. The total plant sample was 636 ha in Central Kalimantan. As a result, plant growth factors can significantly impact oil palm productivity as measured by the components of oil palm plant production: fresh bunch production per hectare, average bunch weight, and the number of oil palm bunches. FFB tonnage and mean bunch weight increase each year from age 3 to age 13, according to a quadratic regression pattern, whereas the number of palm clusters, in contrast, decreases in number with increasing plant age. This study was intended to serve as a reference and source of information for making production decisions for oil palm plantations to achieve optimal results.

AMINO ACID COMPOSITION AND FORAGE VALUE OF GLYCYRRHIZA PALLIDIFLORA MAXIM. GRASS INTRODUCED IN KUZBASS

The purpose of the work is to study the pale-flowered licorice (Glycyrrhiza pallidiflora Maxim.) of the legume family (Fabaceae) herb amino acid composition and forage value, introduced in the Kuzbass. Eighteen proteinogenic amino acids were identified in the raw materials of the third and fourth years of introduction. Eight of them are irreplaceable and ten of them are replaceable. The amino acids total content differed significantly by years and amounted to 6.266±0.89% in the third year and 12.541±0.51% in the fourth year. The content of tryptophan, arginine, leucine+isoleucine, valine, histidine, aspartic acid, and serine varied more strongly from year to year. The content of proline, tyrosine, and methionine varied less. Amino acids with polar negatively charged radicals (acidic) prevail. Their part of the total amino acid content averages 36.20%. Amino acid’s part with non-polar radicals (neutral) is slightly less – 31.80%. The smallest specific weight had amino acids with polar positively charged radicals (basic) 11.85%. Aspartic and glutamic acids, leucine+isoleucine, arginine, serine, proline were characterized by a larger part of the total amino acids.&#x0D; The crude fat, protein, ash, Barnstein protein, nitrogen-free extractive substances and phosphorus content reached the highest values in the third and fourth years. The crude fiber and calcium amount decreased with increasing plant age. Metabolic energy and energy feed units for raw nutrients for cattle averaged 8.98 MJ/kg and 0.90, respectively. The highest values were reached in the third and fourth years of cultivation. Thus, pale-flowered licorice grass is a promising plant as a fodder crop and for the preparation of feed additives.

Changes in growth characteristics and secondary metabolites in Sinopodophyllum hexandrum with increasing age

Sinopodophyllum hexandrum is a perennial rhizomatous herb that produces the highly valued lignin podophyllotoxin (PPT). Although the effects of environmental factors on growth and secondary metabolites accumulation have been revealed, the changes with increasing plant age have not yet been conducted. Here, growth characteristics, contents of lignans and flavonoids, and expression levels of key genes in 2- to 9-year-old plants were systematically examined. The growth parameters significantly increased, and there were three distinctly morphological variants with single, two, and three leaves with increasing plant age. The accumulation of two lignans PPT and 4'-demethylepipodophyllotoxin (4'-DMEP), three target flavonoids, total flavonoids and phenolic, as well as in vitro antioxidant capacity maximized at 5–6 years. The expression levels of 8 key genes participating in lignan and flavonoid biosynthesis were up-regulated with increasing plant age. The findings provide the compelling evidence to guide sustainable cultivation and collection of S. hexandrum.

Effect of host-plant age on the performance of the root-feeding flea beetle Heikertingerella sp., a biological control agent for Tecoma stans in South Africa

ABSTRACT Age influences host-plant quality, which is a key determinant of the fitness of herbivorous insects and hence biological control agents of invasive plants. We assessed the effect of host-plant age on the performance of the root-feeding flea beetle Heikertingerella sp. (Coleoptera: Chrysomelidae: Galerucinae), which was recently approved for release against the invasive tree Tecoma stans (L.) Juss ex Kunth var. stans (Bignoniaceae) in South Africa. Using similar-sized plants that were aged from one to three years, our aim was to determine an optimal host-plant age to facilitate mass-rearing of the beetle for impending releases. While significantly more F 1 progeny were produced with increasing plant age, presumably due to larger root masses in progressively older plants, plant age did not influence the size of the F 1 adults. There was no significant effect of plant age on the survival and percentage of leaves damaged by the P 1 adults. Tecoma stans plants of all ages produced significantly fewer leaves when exposed to feeding by Heikertingerella sp. adults and their larval progeny, relative to the unexposed control plants. Irrespective of plant age, adults displayed higher feeding intensity on the younger leaves at the top sections of the plants than on the older leaves on the middle and bottom sections. Although plants of all three ages were suitable for adult feeding and survival in quarantine cultures, progressively older plants are best suited for F 1 progeny production and therefore for the mass-rearing of Heikertingerella sp. for releases.

Densidade populacional da lagarta-do-cartucho do outono, Spodoptera frugiperda (Smith e Lepidoptera: Noctuidae), e a sua resposta a alguns fenômenos ecológicos na cultura do milho

The fall armyworm [FAW; Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae)], is considered a serious invasive pest that poses a serious threat to world food security. It can completely devastate a whole country's cereal crops. Therefore, the present work is the 1st field trial in Egypt to elucidate some ecological aspects of S. frugiperda on maize plants (Single-Hybrid 168 Yellow Corn cultivar) at Esna district, Luxor Governorate, Egypt, throughout two sequential growing seasons of maize (2021-2022). Three insect parameters were used, i.e., egg masses, number of larvae, and percentage of damaged corn plants. Effects of certain climatic conditions and corn plant ages on S. frugiperda seasonal activity and damaged plants percentage were also estimated. S. frugiperda population initiated to attack maize plants from the 3rd week of June until the harvest in every season. S. frugiperda had two seasonal activity peaks in terms of egg masses numbers and three peaks regarding the larval population density/season. Its damage percentage increased with increasing plant age weekly. The mean of S. frugiperda egg masses were 2.83 ± 0.40 and 2.96 ± 0.45 mass /10 corn plants in 2021 and 2022, respectively. While, the overall mean larval populations were 13.41 ± 0.52 and 13.03 ± 0.46 larvae/10 plants, during the two growing seasons, respectively. Corn plant damage percentages reached 68.54 ± 2.71 and 60.42 ± 2.92% in 2021 and 2022, respectively. The combined effects of both the weather conditions and maize plant ages were highly significant on egg masses, larvae population density, and damage percentage, and varied from one season to another. The mean daily maximum temperature was the most effective variable on egg masses and the larval population. Maize plant age had a clear effect on the damage percentage caused by the larvae in the field during the two years of the study. The dramatic spread of FAW and the consequent damage (that appeared in different countries of America, Africa, and Asia) mean that different management approaches must be sought for the small and large-scale producers by using available technologies for smallholder farmers will eliminate pest damage without access to reach to an economic Injury level. This information may assist the decision maker when planning the S. frugiperda IPM program for maize plants and its surveillance.

Enhanced mutualism: A promotional effect driven by bacteria during the early invasion of Phytolacca americana.

The enhanced mutualism hypothesis postulates that invasive plants promote self-growth by enriching beneficial microbes to establish a positive soil feedback. However, the roles of soil microorganisms may vary with increasing time for plant growth. Research on changes in soil microbial communities over time has important implications for understanding the mechanisms underlying plant invasion. Due to the difficulty in evaluating the duration of plant growth, few studies have quantified the changes in soil microorganisms with increasing plant age. This study focuses on the invasive weed Phytolacca americana L., which has growth rings in the main root. We conducted a two-stage experiment in the field and greenhouse to explore the soil feedback changes with duration of plant growth. We determined the effects of P. americana at different ages on the soil microbial community and soil properties and performed a soil inoculation experiment to quantify the influence of soil microbes on seed germination and seedling performance. We found that the content of some soil nutrients, namely total nitrogen, total phosphorus, nitrate-N, and available phosphorus, significantly decreased with increasing growth age of P. americana, whereas the available potassium showed an opposite increasing trend. The P. americana growth age also significantly influenced the soil bacterial community structure. However, this phenomenon did not occur in the fungal community. In the bacterial community, the relative abundance of plant growth-promoting bacteria showed an increasing trend. The soil inoculation experiment had high seed germination rates and biomass accumulation when the plants were grown in conditioned soil from P. americana growth within 5years, suggesting a positive plant-soil feedback. However, the promoting effect disappeared in conditioned soil from 10years of age. Our findings demonstrate that plant growth-promoting bacteria significantly accumulated in the soil during the early stages of P. americana invasion, and that the strength of enhanced positive feedback may play a crucial role in facilitating P. americana invasion. This study highlights the changing nature of plant-microbe interactions during biological invasion and illustrates how bacteria could contribute to the initial success of P. americana, providing new insights into the underlying mechanisms of plant invasion.

Evidence that mitochondrial alternative oxidase respiration supports carbon balance in source leaves of Nicotiana tabacum

Alternative oxidase (AOX) represents a non-energy conserving pathway within the mitochondrial electron transport chain. One potential physiological role of AOX could be to manage leaf carbohydrate amounts by supporting respiratory carbon oxidation reactions. In this study, several approaches tested the hypothesis that AOX1a gene expression in Nicotiana tabacum leaf is enhanced in conditions expected to promote an increased leaf carbohydrate status. These approaches included supplying leaves with exogenous carbohydrates, comparing plants grown at different atmospheric CO2 concentrations, comparing sink leaves with source leaves, comparing plants with different ratios of source to sink activity, and examining gene expression over the diel cycle. In each case, the pattern of AOX1a gene expression was compared with that of other genes known to respond to carbohydrates and/or other factors related to source:sink activity. These included GPT1 and GPT3 (that encode chloroplast glucose 6-phosphate/phosphate translocators), SPS (that encodes sucrose phosphate synthase), SUT1 (that encodes a sucrose/H+ symporter involved in phloem loading) and UCP1 (that encodes a mitochondrial uncoupling protein). The AOX1a transcript amount was higher following the leaf sink-to-source transition, and in plants with higher source relative to sink activity due to increasing plant age. Further, these effects were amplified in plants grown at elevated CO2 to stimulate source activity, particularly at end-of-day time periods. The AOX1a transcript amount was also higher following treatment of leaves with carbohydrate, in particular sucrose. Overall, the results provide evidence that, while source leaf sucrose accumulation may signal for a down-regulation of sucrose synthesis and transport, it also signals for means to manage the excess cytosolic carbohydrate pools. This includes increased AOX respiration to support carbon oxidation pathways even if energy charge is high, in combination perhaps with some return flux of carbohydrate from cytosol to stroma through the GPT3 translocator. As discussed, these activities could contribute to maintaining plant source:sink balance, as well as photosynthetic and phloem loading capacity.

Short Communication: Analysis of the ultimate wood composition of a forest plantation species, Eucalyptus pellita, to estimate its bioelectricity potency

Abstract. Haqiqi MT, Hudaya D, Septiana HA, Ramadhan R, Yuliansyah, Suwinarti W, Amirta R. 2022. Short Communicarion: Analysis of the ultimate wood composition of a forest plantation species, Eucalyptus pellita, to estimate its bioelectricity potency. Biodiversitas 23: 2389-2394. Eucalyptus pellita F. Muell is one of the short rotation wood crop species widely planted in tropical countries, including Indonesia. Woody biomass obtained from this species is commonly utilized to produce fiber in the pulp and paper industry. Due to the growing interest in expanding E. pellita plantations, the potential application of E. pellita woody biomass to provide sustainable energy feedstock has been studied. Therefore, this study aimed to investigate the ultimate composition of E. pellita wood (carbon (C), hydrogen (H), and oxygen (O)) to estimate its higher heating value (HHV) and bioelectricity potency. The wood samples were harvested at different plant ages, from the first to the fifth year. The percentage of biomass composition, including cellulose, hemicellulose, lignin, and extractives, was also calculated. The results demonstrated that lignin in the E. pellita wood increased to align with the increased plant age. Thus, this pattern was followed by significantly increased C content in the wood since lignin contained a primary source of C. Hence, this condition might enhance the HHV and electricity potency. The ratio of H/C and O/C was found to be one of the most promising factors in improving HHV compared to the extractive/lignin ratio. In the fifth year, the electricity potency of E. pellita showed the highest value (1.71 MWh ton-1). Therefore, this study suggests that E. pellita possesses the potential to be one of the promising crops for green electricity production.

The growth of Paraserianthes falcataria at three different plant ages and soil thickness classes on reclamation sites of post-coal mining areas in East Kalimantan, Indonesia

Abstract. Mulyadi, Ruhiyat D, Aipassa MI, Hardwinanto S. 2022. The growth of Paraserianthes falcataria at three different plant ages and soil thickness classes on reclamation sites of post-coal mining areas in East Kalimantan, Indonesia. Biodiversitas 23: 1930-1937. Sengon (Paraserianthes falcataria (L.) Nielsen syn. Falcataria moluccana (Miq.) Barneby &amp; J.W. Grimes) is a fast-growing species commonly used for reclamation of post-coal mining areas in East Kalimantan. The study aimed to determine the impact of different thicknesses of topsoil applied at some reclamation sites after coal mining activities on the growth of P. falcataria. Three coal mining companies were chosen as study areas, i.e., PT Bukit Baiduri Energi (BBE), PT. Mahakam Sumber Jaya (MSJ), and PT. Kaltim Prima Coal (KPC). The regolith soil layer at the reclamation site had three thickness classes (0-10 cm, 0-30 cm, 0-100 cm), and the P. falcataria growing on reclamation had three ages, i.e.,&lt; 2 yrs old (initial growth phase), 2-5 yrs old (tending phase), and &gt; 5 yrs old (independent growth phase). The number of surviving plants, plant height, and plant stem’s diameter were recorded, and the data were analyzed using ANOVA and the least significant difference at 5% level. The results showed that no significant difference in the number of trees among different ages of P. falcataria plantation was found at MSJ. In contrast, at BBE and KPC the number of surviving trees decreased significantly with the increasing plant age. The growth of the plant (height, diameter) increased significantly along with plant age in all sites. The interaction between the top soiling thickness factor and plant age factor produced no different result in plant growth except for plant height at BBE. The P. falcataria plants had not been able to lower the surface soil density in the land reclamation area.

Interactive Effects of Cd and Pb on the Photosynthesis Efficiency and Antioxidant Defense System of Capsicum annuum L.

In this study, the interactive effect of Cd and Pb on the growth of Capsicum annuum L. was studied through pot experiments, and the indicators of photosynthesis efficiency (PE) and antioxidant defense system (ADS) were measured at different plant ages. Single Pb stress on PE and ADS was stronger than single Cd stress at the first month. Both the PE and ADS response showed a significant decrease under the combined stress of Cd and Pb, which was primarily dependent on the Pb concentration. With increasing plant age, the PE and response of non-enzymatic ADS exhibited dramatic decreases under Cd and/or Pb stress, and the activities of enzymatic ADS showed increases to some extent. The factorial analysis showed that Cd and Pb had an interactive effect to reduce PE, while slightly enhanced the activities of enzymatic ADS. Those results are useful to explore the interaction between Cd and Pb in the combined stress and understand their accumulation in the plants.

Mineral nitrogen accumulation and its spatial distribution in soils in dense planting dwarf rootstock apple orchard on the Weibei dry plateau, Northwest China

With the rapid development of dense apple tree plantings with the dwarf rootstock cultivation method, determining accumulation and distribution characteristics of soil mineral nitrogen in densely planted orchards with dwarf rootstock is important to enable scientific fertilization of apple orchards. We investigated densely planted apple orchards with dwarf rootstocks and different plant ages (6 a, 9 a, and 12 a). We collected soil samples under trees, between trees, between rows, and at the midpoints between the trees and rows, and examined the accumulation and distribution characteristics of nitrate, ammonium, and mineral nitrogen. The cumulative amount of nitrate in the 0-300 cm soil layer increased with plant age. The difference between orchards with different plant ages was significant and showed the trend 6 a<9 a<12 a. The cumulative amount of nitrate increased from 1729 kg·hm-2 to 3771 kg·hm-2 with increasing plant age. The ammonium content was low for orchards of all plant ages and had little effect on the accumulation and spatial distribution of mineral nitrogen. There were two accumulation peaks of nitrate nitrogen in the vertical direction. The depth of soil layer where the second accumulation peak was located decreased from 180 cm to 220 cm with increasing plant age. In the horizontal direction, soil nitrate nitrogen content between rows increased from 27 mg·kg-1 to 138 mg·kg-1 with increasing plant age, representing a more than 400% increase. The difference between orchards with different plant ages was significant. In summary, excessive usage of nitrogen fertilizer and serious leaching of nitrate were problematic in all orchards with different ages. Less nitrogen fertilizer should be applied, and anti-seepage measures should be used at the fertilization location to prevent the leaching of nitrate to deep layers.

Sugar content variation in elephant grass germplasm

ABSTRACT: The objective of this study was to estimate sugar content variation (°Brix) in 95 accessions from the elephant grass germplasm active bank of Embrapa Dairy Cattle research center, located in Coronel Pacheco, MG, Brazil. The accessions with the highest sugar content were identified, and the effect of plant age on sugar concentration was evaluated. The experiment was conducted in randomized blocks design with two replications. Sugar content analysis occurred twice during the growth-cycle (at 70 and 100 days) along two points of the stem, one 30 cm from the base and the other at the midpoint. The analysis of variance considered the split plot model, with accessions as main plots and plant age as subplots. The means were compared using the Scott Knott test. While there was sugar content variation between accessions, increased plant age had no significant effect on the sugar content. However, some accessions did have a significant increase or decrease in sugar content as they aged. The highest and lowest mean sugar content was 6.96% (in the accession BAG80) and 4.03% (in the accession BAG13) °Brix, respectively.

Jute leaves: A potential sources of lycopene

ABSTRACT Jute (Corchorus sp.) leaves may contain lycopene, a strong antioxidant, but amounts in jute leaves are not known. The study was undertaken to estimate the lycopene content in fresh, processed, and preserved jute leaves of the cultivated jute species C. olitorius L. and C. capsularis L. The highest lycopene content was in 45-day-old fresh leaves which gradually decreased with increasing plant age. Among processing methods, leaves soaked in vinegar had the highest lycopene for C. olitorius but in C. capsularis the highest lycopene was in leaves boiled with water and salt for 15 min. All the processing methods led to increased availability of lycopene compared to fresh leaves. Preserved jute leaves retained lycopene following drying and preservation at −20°C. The highest lycopene was from cold dried preserved leaves at 4°C and then air dried leaves at 33–35°C; the lowest lycopene content was from leaves dried in an oven at 100°C. Lycopene content in leaves differed due to plant ages. Lycopene in 45-day-old plant jute leaves was more than doubled compared to fresh red tomatoes. Further evaluation is needed to determine if consumption and digestion affect the available lycopene content in jute leaves available to humans.

L-3,4-dihydroxyphenylalanine Accumulation in Faba Bean (Vicia faba L.) Tissues during Different Growth Stages

L-3,4-dihydroxyphenylalanine (L-dopa)-rich faba (Vicia faba L.) tissues are a potentially useful source for its pharmaceutical purpose, although the species contains health curious vicine and convicine in the seeds. We determined the contents of L-dopa, vicine, and convicine in different tissues of faba plants throughout the entire growth period. The three compounds accumulated in germinating sprouts and showed high contents at 8 days of germination, especially in the epicotyl containing 132.33 mg∙g−1 DW of L-dopa, 19.81 mg∙g−1 DW of vicine, and 10.38 mg∙g−1 DW of convicine, respectively. We compared the contents of the three compounds among leaves of different ages in plants at different growth stages. The samples could be ranked, from highest to lowest content, ranging from 11.11 to 81.82 mg∙g−1 DW, as follows: new leaves &gt; young leaves &gt; old leaves; and vegetative &gt; flowering &gt; ripening. Vicine and convicine were not detected in leaves or flowers. The L-dopa content was high in flowers, especially young flower buds, ranging from 36.51 to 100.70 mg∙g−1 DW. In older flowers, the L-dopa content tended to decrease as the calyx and petal parts developed. In addition, the three compounds showed decreasing contents in pods, stems, and roots with increasing plant age. The results of this study provide information on the timing and extent of L-dopa, vicine, and convicine accumulation in different faba tissues, and indicate that various by-products, especially new/young leaves and flowers, are potential sources of natural L-dopa.

Leaf Pigment, Phenolic Content, and Production of Green Shallot of Five Different Shallot Varieties

Five shallot varieties namely ‘Bauji’, ‘Bantaeng’, ‘Tuk Tuk’, ‘Rubaru’, and ‘Palasa’ were examined for their leaf pigment, total phenolic content, leaf tissue nutrient analysis, and green shallot production. The experiment was conducted in in Cikabayan greenhouse, IPB University, Dermaga, Bogor, arranged in a randomized complete block design with single factor (variety) and three replications. The observations were carried out three times in the maximum vegetative period, consisting of 20, 30, and 40 days after planting. The result showed that ‘Palasa’ had the highest leaf pigment content, such as chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid, while the anthocyanin content fluctuated between the varieties and observation times. ‘Palasa’ also had the highest sulfur content in the leaf tissues. On the contrary, ‘Palasa’ had the lowest production compared to other the varieties. Meanwhile, ‘Bantaeng’ had the highest green shallot production, total nitrogen, and total phosphorus content in the leaf tissues. Total phenolic content fluctuated in the five varieties and observation times. The highest total phenolic content was in ‘Tuk Tuk’, observed 20 days after planting. The principal component analysis (PCA) showed that the five shallot varieties formed three clusters. The first was ‘Palasa’, the second cluster was ‘Bauji’, ‘Tuk Tuk’, and ‘Rubaru’, while the third cluster was ‘Bantaeng’. ‘Palasa’ had the highest content of leaf pigment, while Bantaeng had the highest leaf production. Leaf pigment and total phenolic content changed along with the increasing plant age in all varieties.

Pengendalian trips, Megalurothrips usitatus (Bagnall) pada tanaman kacang hijau (Vigna radiata): Pengaruh waktu tanam dan periode pengendalian

Megalurothrips usitatus (Bagnall) merupakan hama utama tanaman kacang hijau yang dapat menyebabkan gagal panen, oleh sebab itu dilakukan penelitian yang bertujuan untuk mengetahui waktu tanam kacang hijau dan waktu pengendalian hama trips yang tepat, serta resiko kehilangan hasil yang minimal. Penelitian ini dilakukan di kebun percobaan Muneng, Probolinggo, Jawa Timur pada musim kemarau 2015. Rancangan percobaan yang digunakan adalah rancangan petak terbagi (split plot) dalam acak lengkap dengan waktu tanam sebagai whole plot (petak utama) dan perlakuan waktu pengendalian kimia sebagai sub plot (anak petak) dengan 2 ulangan. Enam waktu tanam sebagai petak utama terdiri atas waktu tanam I 20 Mei 2015, tanam II 30 Mei 2015; tanam III 9 Juni 2015; tanam IV 19 Juni 2015; tanam V 29 Juni 2015, dan tanam VI 9 Juli 2015. Sementara, waktu pengendalian kimia menggunakan insektisida fipronil sebagai anak petak terdiri atas 4 perlakuan, yaitu (1) tanpa pengendalian kimia selama fase vegetatif dan generatif (kontrol); (2) pengendalian kimia selama fase generatif; (3) pengendalian kimia selama fase vegetatif; dan (4) pengendalian kimia selama fase vegetatif dan generatif. Hasil penelitian menunjukkan bahwa gejala serangan trips mulai tampak pada 21 hari setelah tanam (HST), ditandai dengan daun trifoliat pertama mengeriting. Populasi trips per tanaman meningkat seiring dengan meningkatnya umur tanaman. Populasi trips tertinggi terdapat pada kombinasi perlakuan waktu tanam II (akhir Mei) dengan perlakuan tanpa pengendalian, yaitu mencapai 17,8 individu pada tanaman umur 18 HST. Kehilangan hasil tertinggi 90,2% terdapat pada perlakuan waktu tanam I (pertengahan Mei) dan waktu tanam II (akhir Mei) sebesar 85,6%, apabila tanaman tidak dikendalikan selama fase vegetatif dan generatif. Bulan Mei merupakan periode kritis tanaman kacang hijau terhadap serangan trips. Dari penelitian ini dapat disimpulkan bahwa untuk mengurangi resiko kehilangan hasil akibat serangan trips, yaitu dengan menghidari bertanam kacang hijau pada bulan Mei. Di daerah endemik serangan trips, pengendalian hama pada awal pertumbuhan tanaman dan selama fase vegetatif merupakan faktor penentu perolehan hasil biji kering kacang hijau. Musim bediding dapat dijadikan pertanda bagi petani agar waspada terhadap serangan hama trips, dan segera melakukan tindakan pengendalian hama agar tidak terlambat.

Effects of rodent-induced disturbance on eco-physiological traits of Haloxylon ammodendron in the Gurbantunggut Desert, Xinjiang, China

Disturbance by rodents alters the morphologies and nutrients of plants as well as the physical-chemical properties of the soils. Changes in plants are considered to be mechanisms of defense against the disturbance by rodents. Rodents gnaw on the assimilating branches of Haloxylon ammodendron (CA Mey.) Bunge and burrow under the bushes in the desert ecosystems of Xinjiang, China. However, eco-physiological responses of different age groups of H. ammodendron to the disturbance by rodents are not well understood. In this study, soil physical-chemical properties under the shrubs and the above-ground morphological, physiological and biochemical features of assimilating branches of H. ammodendron of different age groups (i.e., young, 30–100 cm; middle-aged, 100–200 cm; and mature, >200 cm) in burrowed and non-burrowed (control) areas were studied in 2018. We found that disturbance by rodents significantly increased the crown width and total branching rates of young and middle-aged H. ammodendron. Photosynthetic pigment contents of assimilating branches of H. ammodendron were significantly reduced under the disturbance by rodents. In term of plant nutrients, the main differences among different age groups of H. ammodendron under the disturbance by rodents occurred in the total soluble sugar and reducing sugar contents that decreased in young plants, increased in middle-aged plants, and did not affect in mature plants. Crude protein and phosphorus contents significantly increased, while crude fiber and calcium contents significantly decreased in young plants. Crude fat and calcium contents significantly decreased in middle-aged plants. Soil organic matter (SOM), total nitrogen (TN), available nitrogen (AN) and available potassium (AK) contents in the topsoil (0–20 cm), which are conducive to forming “fertile islands”, also increased under the disturbance by rodents. In particular, soil AN and AK were the major factors affecting the above-ground morphological characteristics of H. ammodendron in burrowed areas. Overall, the response and defense strategies of H. ammodendron to the disturbance by rodents differed among different age groups, and the effect of the disturbance by rodents on H. ammodendron gradually weakened with the increasing plant age.