EFFECTS OF RELATIVE HUMIDITY IN THE CULTURE VESSEL ON THE TRANSPIRATION AND NET PHOTOSYNTHETIC RATES OF POTATO PLANTLETS IN VITRO

The use of an in vitro mist culture systems for the growth of virus free shoots of several potato cultivars has been demonstrated using the “Mystifier®”, several different media and growth regulator concentrations have been used to monitor the efficiency of shoot multiplication and growth. Nodal cuttings of sterile in vitro virus free cultures were used as inocula and the mist was applied at various rates in order to assess optimum sucrose concentrations and mineral concentrations. Murashige and Skoog medium was used and diluted to half and quarter strength. Hardening off the resulting shoots was achieved by passing HEPA filtered air at various rates over the plantlets still in the culture vessel. Conditions for high efficiency hardening off of cultured material has been defined such that plantlets can be transferred directly to greenhouse conditions. The implications and opportunities that are indicated by this work are discussed.

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Simulation of the Time Courses of CO2 Concentration in the Culture Vessel and Net Photosynthetic Rates of Potato Plantlets Cultured Photoautotrophically and Photomixotrophically in Vitro under Different Lighting Cycles

HortScience ◽

10.21273/hortsci.32.3.515f ◽

1997 ◽

Vol 32 (3) ◽

pp. 515F-515

Author(s):

Genhua Niu ◽

Makio Hayashi ◽

Toyoki Kozai

Keyword(s):

Net Photosynthetic Rate ◽

Photosynthetic Rate ◽

Quantitative Relationship ◽

Dry Weight ◽

Co2 Concentration ◽

Ventilation Rate ◽

Culture Vessel ◽

Time Courses ◽

Potato Plantlets

Potato (Solanum tuberosum L. cv. Benimaru) plantlets were cultured under four lighting cycles (photoperiod/dark period: 16 h/8 h, 4 h/2 h, 1 h/0.5 h, and 0.25 h/0.125 h) photoautotrophically (without sugar in the medium), and photomixotrophically (with sugar in the medium) in vitro for 28 days. Simulations of time courses of CO2 concentration in the vessel (Ci) and dry weight accumulation of the plantlets cultured photoautotrophically were conducted using a previously developed model (Niu and Kozai, 1997). While underestimation and overestimation of time courses of Ci in some treatments were observed, the simulated results of Ci and dry weight accumulation of the plantlets generally agreed with the measured ones. The difference of net photosynthetic rate response to Ci throughout the culture period was examined between the plantlets cultured photoautotrophically and photomixotrophically. Quantitative relationship between daily net photosynthetic rate (daily net production) and vessel ventilation rate per plantlet was simulated under various CO2 levels outside the vessel for given sizes of potato plantlets cultured photoautotrophically in vitro to aid appropriate CO2 enrichment and vessel design in commercial micropropagation.

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(304) Effects of Supporting Material and Nutrient Supply Cycle on the Growth of Potato Plantlets in a Nutrient-circulated Micropropagation System

HortScience ◽

10.21273/hortsci.40.4.1011a ◽

2005 ◽

Vol 40 (4) ◽

pp. 1011A-1011

Author(s):

Jung Eek Son ◽

Yil Jang ◽

Jung Hyuk Seo

Keyword(s):

Dry Weight ◽

Nutrient Supply ◽

Culture Vessel ◽

Growth And Survival ◽

In Vitro Plantlets ◽

Retention Characteristics ◽

Supporting Material ◽

Supporting Materials ◽

Potato Plantlets

Supporting materials for rooting have a considerable influence on the growth and quality of in vitro plantlets. Various supporting materials (rockwool, perlite, vermiculite, and polyurethane) and nutrient supply cycles (12, 24, 36, and 48 hours) were examined to find the optimum conditions for photoautotrophic micropropagation of potato plantlets in the nutrient-circulated micropropagation (NCM) system. In the NCM system, nutrient solution was circulated between the culture vessel and the nutrient reservoir. A plug cell tray with 70 plantlets was placed inside. The number of air exchanges was 10 hours under forced ventilation. Nodal leafy cuttings of plantlets were cultured at CO2 concentrations (mol·mol-1)/PPF s (mol·m-2·s-1) of 350/80, 700/120, and 1500/250 on day 5-11, 12-18, and 19-28, respectively, for all treatments. All growth factors of in vitro plantlets grown for 28 days using rockwool, perlite and vermiculite were greater than those grown using polyurethane. Dry weight of plantlets grown using rockwool was eight times greater than those grown using polyurethane. The same results were obtained in the growth and survival percentages 14 days after transplanting to ex vitro conditions. Optimum nutrient supply cycles were 12, 24, and 48 hours when perlite, rockwool, and vermiculite were used as supporting materials, respectively. It was considered that the range of optimum nutrient supply cycle was affected by water retention characteristics of supporting materials. This study proved that the supporting material and the nutrient supply cycle were very important environmental factors in photoautotrophic mass propagation.

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Shoot tip necrosis of in vitro plant cultures: a reappraisal of possible causes and solutions

Planta ◽

10.1007/s00425-020-03449-4 ◽

2020 ◽

Vol 252 (3) ◽

Cited By ~ 1

Author(s):

Jaime A. Teixeira da Silva ◽

Esmaeil Nezami-Alanagh ◽

María E. Barreal ◽

Mafatlal M. Kher ◽

Adhityo Wicaksono ◽

...

Keyword(s):

Relative Humidity ◽

Ethylene Production ◽

Physiological Condition ◽

Shoot Tip ◽

High Relative Humidity ◽

Culture Vessel ◽

In Vitro Shoots ◽

In Vitro Plant ◽

Shoot Tip Necrosis

Abstract Main conclusion Shoot tip necrosis is a physiological condition that negatively impacts the growth and development of in vitro plant shoot cultures across a wide range of species. Abstract Shoot tip necrosis is a physiological condition and disorder that can arise in plantlets or shoots in vitro that results in death of the shoot tip. This condition, which can spread basipetally and affect the emergence of axillary shoots from buds lower down the stem, is due to the cessation of apical dominance. STN can occur at both shoot multiplication and rooting stages. One of the most common factors that cause STN is nutrient deficiency or imbalance. Moreover, the presence or absence of plant growth regulators (auxins or cytokinins) at specific developmental stages may impact STN. The cytokinin to auxin ratio within an in vitro plant can be modified by varying the concentration of cytokinins used in the culture medium. The supply of nutrients to in vitro shoots or plantlets might also affect their hormonal balance, thus modifying the occurrence of STN. High relative humidity within culture vessels and hyperhydricity are associated with STN. An adequate supply of calcium as the divalent cation (Ca2+) can hinder STN by inhibiting the accumulation of phenolic compounds and thus programmed cell death. Moreover, the level of Ca2+ affects auxin transport and ethylene production, and higher ethylene production, which can occur as a result of high relative humidity in or poor ventilation of the in vitro culture vessel, induces STN. High relative humidity can decrease the mobility of Ca2+ within a plant, resulting in Ca2+ deficiency and STN. STN of in vitro shoots or plantlets can be halted or reversed by altering the basal medium, mainly the concentration of Ca2+, adjusting the levels of auxins or cytokinins, or modifying culture conditions. This review examines the literature related to STN, seeks to discover the associated factors and relations between them, proposes practical solutions, and attempts to better understand the mechanism(s) underlying this condition in vitro.

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The Potential Migrated Mechanism of Water-Soluble Components in Pellets Prepared by Wet Extrusion/Spheronization: Effect of Drying Rate

Current Drug Delivery ◽

10.2174/1567201817666201124113741 ◽

2020 ◽

Vol 17 ◽

Author(s):

Bingwei Wang ◽

Jianping Liu ◽

Zhenghua Li ◽

Yulong Xia ◽

Shuangshuang Zhang ◽

...

Keyword(s):

Relative Humidity ◽

Water Soluble ◽

In Vitro Dissolution ◽

Drying Rate ◽

Scanning Calorimetry ◽

Drying Temperature ◽

Wet Extrusion ◽

Extrusion Spheronization ◽

Soluble Components

Background: At present, there were numerous researches on the migration of components in tablets and granules, the investigation in the pharmaceutical literatrue concerning the effect of drying rate on the migration of water-soluble components of pellets was limited. Temperature and relative humidity (RH) were crucial parameters during the drying process which was an essential step in the preparation of pellets via wet extrusion/spheronization. To quantify these variables, the water loss percentage of pellets per minute was defined as drying rate. Objective: The study aimed to investigate the influence of drying rate on the migration of water-soluble components in wet pellets and the potential migrated mechanism. Methods: The pellets containing tartrazine as a water-soluble model drug and microcrystalline cellulose as a matrix former were prepared by extrusion/spheronization and dried at four different drying temperature and relative humidity. Afterward, the extent of migrated tartrazine was assessed regarding appearance, in-vitro dissolution test, Differential Scanning Calorimetry, X-Ray Powder Diffraction, Attenuated total reflectance Fourier transform infrared spectroscopy and Confocal Raman Mapping. Results: Results demonstrated that red spots of tartrazine appeared on the surface of pellets and more than 40% tartrazine were burst released within 5 minutes when pellets dried at 60℃/RH 10%. While pellets dried at 40℃/RH 80%, none of these aforementioned phenomena was observed. Conclusion: In conclusion, the faster drying rate was, the more tartrazine migrated to the exterior of pellets. Adjusting drying temperature and relative humidity appropriately could inhibit the migration of water-soluble components within wet extrusion/spheronization pellets.

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Effect of the Presence/Absence of Sugar in the Medium and Natural/Forced Ventilation on the Net Photosynthetic Rates of Potato Expants in vitro.

Plant tissue culture letters ◽

10.5511/plantbiotechnology1984.8.105 ◽

1991 ◽

Vol 8 (2) ◽

pp. 105-109 ◽

Cited By ~ 27

Author(s):

M. NAKAYAMA ◽

T. KOZAI ◽

K. WATANABE

Keyword(s):

Forced Ventilation ◽

Photosynthetic Rates

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Synthesis of 70K stress protein by human leukocytes: effect of exercise in the heat

Journal of Applied Physiology ◽

10.1152/jappl.1991.70.1.466 ◽

1991 ◽

Vol 70 (1) ◽

pp. 466-471 ◽

Cited By ~ 59

Author(s):

A. J. Ryan ◽

C. V. Gisolfi ◽

P. L. Moseley

Keyword(s):

Protein Synthesis ◽

Relative Humidity ◽

Treadmill Exercise ◽

Stress Protein ◽

Exercise Bout ◽

Time Dependent ◽

Dependent Manner ◽

Human Leukocytes ◽

Before And After

To determine whether reinduction of 70,000-Da (70K) stress protein synthesis could be used as an assay for thermal history and/or cellular levels of 70K stress protein in hyperthermic humans, leukocytes were obtained before and after 2 h of exercise and then incubated at 37 or 41 degrees C. Five healthy males completed 2 h of treadmill exercise consisting of running at 4–6 km/h for 30–45 min followed by 75–90 min of walking up a 2–10% grade. This exercise bout was performed by two subjects in hot (46 degrees C, 15% relative humidity) and by five subjects in cooler (30 degrees C, 40% relative humidity) environmental conditions. Exercise resulting in rectal temperature (Tre) less than 40 degrees C did not alter the amount of 70K stress protein synthesized by leukocytes incubated at 41 degrees C. In contrast, exercise resulting in Tre greater than 40 degrees C reduced the amount of 70K stress protein synthesized by leukocytes incubated at 41 degrees C. A protein immunoblot, probed with an antibody specific for the inducible 72K stress protein, showed that the reduction of 35S-labeled 70K stress protein in these postexercise leukocyte samples occurred without marked elevations of this protein. In vitro incubation of human leukocytes at 40 degrees C for 15–120 min reduced, in a time-dependent manner, the amount of 70K stress protein synthesized during a subsequent 41 degrees C heat stress. This reduction of 70K stress protein synthesis in 41 degrees C-treated leukocytes was abolished when cycloheximide was present during the 40 degrees C preincubation.(ABSTRACT TRUNCATED AT 250 WORDS)

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