Gerbera leaf nutritional status as a cut flower cultivated with different doses of nitrogen and calcium

Vegetative tissue analyses might help to diagnose nutritional status of a crop. Foliage diagnosis is an effective method to set up balanced fertilization procedures. The current work aims to evaluate nutrient contents of two gerbera leaf sampling periods as a cut flower cultivated in pots with different doses of nitrogen (N) and calcium (Ca) under greenhouse conditions. The experiment was carried out in a protected environment, shelter type, in a container containing substrate in a 3x3+1 factorial scheme. Three doses of N (0.07, 0.15 or 0.2 g L-1) or three doses of Ca (0.02, 0.03 or 0.04 g L-1) were applied every 15 days. Control plants did receive neither N nor Ca. The substrate was analyzed before and after cultivation, and at the end of production years, as well as completely expanded leaves were collected for nutrient analyses. There was not significant interaction between N and Ca doses. Regarding the sampling period or doses of N and Ca, the determined macronutrient concentrations were in the following order of N>K>Ca>P>S>Mg. The micronutrient concentrations were in the following order of Fe>Mn>B>Zn>Cu. Except for K, all the other nutrient concentrations were in the recommended range for gerberas production.

Tannin Concentration of Gyrinops Tea Taken Form Different Agarwood Plantation and Different Processing Method

Tannin is one of the essential components that determine the quality of herbal tea products. This research aims to conduct a quantitative tannin assay of Gyrinops tea with different leaf sampling locations and processing methods. Factorial Completely Randomized Design was used as an experimental design with two treatment factors. The first factor is sampling location (Kekait, Lingsar, and Pejaring). The second factor is the processing method (Fresh leaves and Dried leaves). A titrimetric method with KMnO4 and Indigo carmine reagent was used for quantitative tannin measurement. ANOVA and DMRT at a 5% significant level were used for tannin concentration analysis. The result indicated that the first, second, and interaction factors significantly affected tannin concentration. Drying the G. versteegii leaves could increase the tannin concentration of the Gyrinops tea product. G. versteegii leaves taken from Kekait have shown highest tannin concentration among other regions. It could be concluded that dried G. versteegii leaves Kekait could produce Gyrinops tea with high quality based on tannin concentration measurement.

The pathway of starch synthesis in Arabidopsis thaliana leaves

Many plants accumulate transitory starch reserves in their leaves during the day to buffer their carbohydrate supply against fluctuating light conditions, and to provide carbon and energy for survival at night. It is universally accepted that transitory starch is synthesized from ADP-glucose (ADPG) in the chloroplasts. However, the consensus that ADPG is made in the chloroplasts by ADPG pyrophosphorylase has been challenged by a controversial proposal that ADPG is made primarily in the cytosol, probably by sucrose synthase (SUS), and then imported into the chloroplasts. To resolve this long-standing controversy, we critically re-examined the experimental evidence that appears to conflict with the consensus pathway. We show that when precautions are taken to avoid artefactual changes during leaf sampling, Arabidopsis thaliana mutants that lack SUS activity in mesophyll cells (quadruple sus1234) or have no SUS activity (sextuple sus123456) have wild-type levels of ADPG and starch, while ADPG is 20 times lower in the pgm and adg1 mutants that are blocked in the classical pathway of starch synthesis. We conclude that the ADPG needed for starch synthesis in leaves is synthesized primarily by ADPG pyrophosphorylase in the chloroplasts.Significance statementMutant analysis shows that sucrose synthase makes no significant contribution to transitory starch synthesis in Arabidopsis leaves, resolving a 20-year old controversy about one of the most important pathways of photosynthetic metabolism.

Leaf nutrient status of some grafted-pear rootstocks influenced by different soil types

Aim of study: Determining leaf nutrient status of some grafted-pear rootstocks grown under different calcareous soil types.Area of study: The Horticultural Research Station of Kamalabad, Karaj, Iran.Material and methods: Leaf mineral element concentrations were determined in 2015, 2016, 2017, and 2018. Leaf sampling was carried out about 90 days after full bloom. The N-content was estimated by the Kjeldahl method. Total concentration of calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn), and boron (B) were also determined by the atomic absorption spectrophotometry, and phosphorus (P) and potassium (K) were analyzed using the flame photometry. The deviation from optimum percentage (DOP) and its correlation with the ΣDOP of macro- and micro-nutrients were used to determine the nutritional status of the studied plants.Main results: In clay loamy soil pyrodwarf rootstock, which was grafted with 'William Duchess' scion, presented a more suitable balanced nutritional index than other rootstocks/scion combinations. The OHF69 rootstock grafted with 'Daregazi' offered better balanced nutritional values in fairy lime silt-loamy soil, whereas the pyrodwarf rootstock grafted with 'Louise Bonne' scion in less lime silt-loamy soil was found to have higher values than other studied rootstocks/scion combinations in terms of nutrient concentration.Research highlights: The study determined effective solutions to the field problems of calcium carbonate equivalent which distinctly affect the soil properties related to plant growth. It also revealed the most suitable pear rootstock/scion combinations in different calcareous soil types for orchard establishment in arid and semi-arid regions.

Evaluation of Two-Leaf Sampling Units to Estimate Sugarcane Aphid (Hemiptera: Aphididae) Economic Thresholds in Commercial Grain Sorghum

Sugarcane aphid Melanaphis sacchari Zehntner is a significant economic pest of grain sorghum in the United States. Effective monitoring and early detection are cornerstones for managing invasive pests. The recently developed binomial sequential sampling plan estimates sugarcane aphid economic thresholds (ETs) based on classification whether a 2-leaf sample unit has ≤ or ≥ 50 M. sacchari. In this study, we evaluated eight 2-leaf sampling units for potential use in the sequential sampling plan. From 2016 through 2017, whole plant counts of M. sacchari were recorded non-destructively in situ on sorghum plants from 140 fields located in five states. Plant canopies were stratified into three categories. Two leaves from each stratum were used to compare linear relationships between M. sacchari numbers per two-leaf sample unit and total M. sacchari density per plant. Analysis revealed that two randomly selected leaves from the middle stratum accounted more variation for estimating M. sacchari density when compared to two leaves from the other strata. Comparison of eight two-leaf sampling units within plant growth stages were variable in quantifying variation of M. sacchari densities. When growth stages were combined, the standard uppermost + lowermost leaf sample unit and a unit consisting of two randomly selected leaves from the middle stratum revealed little difference in their enumeration of variation in M. sacchari density. Because other sample units were either less predictive and/or more variable in estimating M. sacchari density, we suggest that the (L1+U1) sample unit remain the preferred method for appraising M. sacchari ETs.

DETEKSI Liberibacter spp. PADA JERUK SIAM BERGEJALA KLOROSIS DISERTAI BERCAK HITAM DENGAN Polymerase Chain Reaction

Liberibacter bacteria are one of the pathogenic bacteria in citrus plants. Siam Citrus Plant in Setapok Village, Singkawang City, suspected to be infected with Liberibacter spp. bacteria by showing patterns of symptoms of chlorosis accompanied by patches. This study aims to detect Liberibacter spp. on Siam Citrus leaves with symptomatic chlorosis with patches. Leaf sampling uses the roaming method in one of the citrus plantations in Setapok Village, Singkawang City. Detection of Liberibacter spp. done by PCR (Polymerase Chain Reaction) technique. Detection of bacterial DNA through several stages namely, isolation of bacterial plasmid DNA, 16S rDNA gene amplification with a thermocycler machine, and visualization using a set of electrophoresis devices. Electrophoresis results show the presence of DNA band lines, with a size of around 1100 bp for OI1 and OI2c primers, and DNA bands of 703 bp for A2 and J5 specifics. The results showed that there were Liberibacter spp. in the symptomatic chlorosis of Siam Citrus leaves accompanied by patches.

Temporal Variation of Phenolic and Mineral Composition in Olive Leaves Is Cultivar Dependent

In order to investigate the potential of various olive cultivars and leaf sampling times for phytochemical farming practice in Croatia, phenolic and mineral composition was determined in olive leaves of four Croatian cultivars and Italian cultivar Leccino collected at three occasions, in October 2017, January 2018, and March 2018. Istarska bjelica turned out to have the largest phytochemical potential among the investigated cultivars due to steady high oleuropein concentrations found in its leaves. The concentration of main phenolic components in Istarska bjelica leaves changed only slightly during the sampling period, suggesting the possibility of its higher capability for low air temperatures stress resistance and different metabolic response compared to the other studied cultivars. Low air temperatures increased the oleuropein level and antioxidant activity in leaves of Leccino, Oblica, Levantinka, and Drobnica cultivars, which may be of crucial phytochemical farming interest. Each of the investigated olive cultivars was characterized by a specific leaf mineral nutrient composition, which could have had a specific role in their interplay with phenols.

Citrus Leaf Sampling Procedures for Nutrient Analysis

To maintain balanced nutrients for optimal tree growth, citrus growers need to assess trees’ nutritional requirements. These assessments help prevent any nutrient deficiency or toxicity from compromising tree health and yield or reducing revenue. This new illustrated two-page instructional sheet gives a basic procedure for the citrus leaf sampling process, as well as additional suggestions for HLB-affected trees. Written by Tripti Vashisth, Jamie D. Burrow, Davie Kadyampakeni, and Rhuanito S. Ferrarezi, and published by the UF/IFAS Horticultural Sciences Department.https://edis.ifas.ufl.edu/hs1355

Predicting N Status in Maize with Clip Sensors: Choosing Sensor, Leaf Sampling Point, and Timing

Nitrogen (N) losses from agricultural systems increase air and water pollution, and these losses are highly correlated with the excessive fertilization. An adjusted N fertilization is then a key factor in increasing the N fertilizer efficiency, and leaf clip sensors can help to improve it. This study (combining five different field experiments in Central Spain) tried to identify the ability of the clip sensors in maize N status identification and yield prediction, comparing two different devices (SPAD-502® and Dualex®) and identifying the best protocol for maize leaf sampling. As a result, the study demonstrated that different leaf clip chlorophyll sensors presented similar results, although some differences appeared at larger N concentrations. Complementary polyphenol information (as flavonol) can improve the maize N deficiency prediction. Moreover, valuable information for a proper sampling protocol was obtained with this study. It proved that the sampling position (in the leaf and in the plant) and sampling time were crucial for a better estimation of the maize N status. Proper fertilization recommendations could be achieved based on clip chlorophyll sensor measurements.