Plant secondary metabolites are unique sources for pharmaceuticals, food additives, flavors, and industrially important biochemicals. Accumulation of such metabolites often occurs in plants subjected to stresses including various elicitors or signal molecules. Secondary metabolites play a major role in the adaptation of plants to the environment and in overcoming stress conditions. Environmental factors viz. temperature, humidity, light intensity, the supply of water, minerals, and CO2 influence the growth of a plant and secondary metabolite production. Drought, high salinity, and freezing temperatures are environmental conditions that cause adverse effects on the growth of plants and the productivity of crops. Plant cell culture technologies have been effective tools for both studying and producing plant secondary metabolites under in vitro conditions and for plant improvement. This brief review summarizes the influence of different abiotic factors include salt, drought, light, heavy metals, frost etc. o...

https://www.tandfonline.com/doi/pdf/10.4161/psb.6.11.17613

Influence of abiotic stress signals on secondary metabolites in plants

https://pubag.nal.usda.gov/download/25475/PDF

Salinity–mineral nutrient relations in horticultural crops

The function of anthocyanins in green, vegetative tissues has always been a contentious issue. Here we evaluate their proposed photoprotective function since recent findings have shown that anthocyanins reduce photoinhibition and photobleaching of chlorophyll under light stress conditions. Anthocyanins generally accumulate in peripheral tissues exposed to high irradiance, although there are some exceptions (e.g. accumulation in abaxial leaf tissues and in obligatory shade plants) and accumulation is usually transient. Anthocyanin accumulation requires light and generally coincides with periods of high excitation pressure and increased potential for photo-oxidative damage due to an imbalance between light capture, CO2 assimilation and carbohydrate utilization (e.g. greening of developing tissues, senescence and adverse environmental conditions). Light attenuation by anthocyanin may help to re-establish this balance and so reduce the risk of photo-oxidative damage. Although it has been suggested that anthocyanins may act as antioxidants, the association between anthocyanins and oxidative stress appears to relate to the ability of anthocyanins to reduce excitation pressure and, hence, the potential for oxidative damage. The various aspects of anthocyanin induction and pigmentation presented here are compatible with, and support, the proposed general role of anthocyanins as photoprotective light screens in vegetative tissues.

https://nph.onlinelibrary.wiley.com/doi/pdf/10.1046/j.1469-8137.2002.00482.x

Anthocyanins in vegetative tissues: a proposed unified function in photoprotection

Plant transformation is now a core research tool in plant biology and a practical tool for cultivar improvement. There are verified methods for stable introduction of novel genes into the nuclear genomes of over 120 diverse plant species. This review examines the criteria to verify plant transformation; the biological and practical requirements for transformation systems; the integration of tissue culture, gene transfer, selection, and transgene expression strategies to achieve transformation in recalcitrant species; and other constraints to plant transformation including regulatory environment, public perceptions, intellectual property, and economics. Because the costs of screening populations showing diverse genetic changes can far exceed the costs of transformation, it is important to distinguish absolute and useful transformation efficiencies. The major technical challenge facing plant transformation biology is the development of methods and constructs to produce a high proportion of plants showing predictable transgene expression without collateral genetic damage. This will require answers to a series of biological and technical questions, some of which are defined.

PLANT TRANSFORMATION: Problems and Strategies for Practical Application

Publisher Summary The subject of salt tolerance has received a tremendous amount of attention during the past two decades. The concept of developing salt-tolerant plants, even to the degree that they can be grown with seawater, captures the imagination of both the scientific and the public sector. There is a wide range of salt tolerance in vascular plants. Several genera include species that are extreme halophytes and are ecologically competitive only under saline conditions. Crop species primarily are glycophytes, salt-sensitive, and grow well only under cultivated conditions. Domesticated species are provided optimum conditions to obtain high yields. There is currently a need to develop new direction and cohesive impetus in the area of salt-tolerant crops development. Realistic short- and long-range goals need to be established and continually pursued. The information that is known is extensive but fragmented. This chapter outlines some of the issues and strategies concerning selection and breeding for plant salt tolerance, highlights crucial advances in knowledge in recent years, and identifies some of the fundamental gaps in our understanding.

Adaptation of Plants to Salinity

Preface. Glossary. 1. Automation in plant tissue culture -- general introduction and overview J. Aitken-Christie, T. Kozai, S. Takayama. 2. Economic analysis of automated micropropagation I. Chu. 3. Economic aspects of somatic embryogenesis R. Cervelli, T. Senaratna. 4. Systems analysis and engineering P.N. Walker. 5. Engineering aspects of plant propagation in bioreactors P.H. Heyderdahl, O.A.S. Olsen, A.K. Hvoslef-Eide. 6. Mechanical engineering approaches to plant biotechnology Y. Miwa, Y. Kushihashi, T. Kozai. 7. Image analysis for plant cell culture and micropropagation M.A.L. Smith. 8. Image analysis for embryogenesis K. Kurata. 9. Automation of the bioreactor process for mass propagation and secondary metabolism R.R. Leathers, M.A.L. Smith, J. Aitken-Christie. 10. Delivery systems for tissue culture by encapsulation Y. Sakamoto, N. Onishi, T. Hirosawa. 11. A delivery system for naked somatic embryos of interior spruce D.R. Roberts, F.B. Webster, D.R. Cyr, T.K. Edmonds, S.M.A. Grimes, B.C.S. Sutton. 12. Automated systems for organogenesis K. Kurata. 13. Commercialisation of tissue culture and automated systems K.S. Wilson. 14. Environmental control in plant tissue culture -- General introduction and overview T. Kozai, M.A.L. Smith. 15. Physical microenvironment and its effects K. Fujiwara, T. Kozai. 16. Vessels, gels, liquid media, and support systems M.A.L. Smith, L.A. Spomer. 17. The chemical microenvironment R.R. Williams. 18. Carbon nutrition in vitro: Regulation and manipulation of carbon assimilation in micropropagated systems Y. Desjardins, C. Hdider, J. De Riek. 19. Ethylene D. Matthys, J. Gielis, P. Debergh. 20. In vitro acclimatization M. Ziv. 21. Low temperature storage of plant tissue cultures B.W.W. Grout. 22. Environmental measurement and control systems T. Kozai, Y. Kitaya, K. Fujiwara, M.A.L. Smith, J. Aitken-Christie. Index.

Automation and environmental control in plant tissue culture

Effects of three variables (vessel type, closure, and explant orientation) on microcutting quality were investigated using five woody species (low shadblow, Ame- fanchier spicata (Lam.) C. Koch (Syn. A. humilus Wieg.); red maple, Acer rubrun L. 'Red Sunset'; border forsythia, Forsythia ×intermedia Zab. 'Sunrise'; apple, Malus ×domestica Borkh. 'McIntosh'; river birch, Betula nigra L.). Uniform shoot explants were oriented vertically or horizontally in three vessel types (60-ml glass culture tubes, 200-ml glass baby food jars, and 350-ml polypropylene GA7 vessels) with and without a Parafilm seal. Visual density per explant obtained by image analysis was increased in larger vessel types, and significantly more shoots were produced from horizontally placed explants. Closure treatments influenced microshoot quality, but trends were species specific. Overall, horizontal explant orientation in larger vessels wthout par- afilm maximized shoot response for most of the species studied. In vitro rooting of microcuttings was significantly enhanced in larger vessels.

/pdf/vessel-type-closure-and-explant-orientation-influence-in-2ppud44b4c.pdf

Vessel type, closure, and explant orientation influence in vitro performance of five woody species

A deliberate change in the growth regulators added to a tissue culture medium can elicit a dramatic response in a cultured plant. This cause-effect relationship is well-recognized, and as a result, growth regulator treatments are carefully designed based on the anticipated consequences to in vitro performance. On the other hand, decisions concerning selection of a containment vessel, or the physical status (phase) of in vitro media are frequently based on cost, availability, or convenience, without much appreciation for their broader repercussions. In fact, these underestimated variables related to the tissue culture vessel (size, shape, closure) or the medium phase (gelling agents, liquid medium, physical supports) can conspicuously modify in vitro plant behavior, often more predictably and cost-effectively than chemical additives to a medium. The potent physicochemical influences dictated by vessels & gels have frequently been cited (Chu et al. 1993; Fujiwara and Kozai 1994, this volume; Kozai et al. 1992; Obeidy and Smith 1990; McClelland and Smith 1990; Smith and McClelland 1991), paving the way for practical management of these tools to optimize tissue culture systems. Many tissue culture laboratories still operate with the assumption that vessels, gels, and related variables are minor players in development of new in vitro strategies, in spite of ample evidence that these underrated variables exert considerable leverage on in vitro productivity, and warrant more comprehensive description and interpretation.

Vessels, gels, liquid media, and support systems

Elicitation of anthocyanin-producing cells of ohelo (Vaccinium pahalae) by both biotic (purified β-glucan and chitosan) and abiotic [sodium ferric ethylenediamine di-(o-hydroxyphenylacetate) FeEDDHA, and CuSO4] elicitors resulted in significant enhancement of anthocyanin accumulation. Anthocyanin production increased up to 1.8 and 1.5-fold over the control in the presence of abiotic elicitors (90 µM FeEDDHA and 20 µM CuSO4, respectively), and increased 1.9 and 1.6-fold in the presence of biotic elicitors (10 mg L−1 β-glucan and 100 mg L−1 chitosan). Maximum anthocyanin production with the two most effective elicitors was achieved when cultures were treated on Day 3 (β-glucan) or Day 0 (FeEDDHA) after the initiation of fresh cell cultures. A concentration-dependent response was exhibited by cultures treated with exogenous methyl jasmonate (MJ). The addition of 0.5 µM MJ alone provoked a 2–3-fold increase in anthocyanin production over that of the control; however, no additive effect on anthocyanin production was observed in any treatments which combined MJ and β-glucan or FeEDDHA. Conditioning of the cells with a preculture in either MJ, β-glucan, or FeEDDHA similarly did not enhance anthocyanin production. Inoculation of cultures elicited by MJ or β-glucan with ibuprofen, a reported inhibitor of jasmonate biosynthesis, dramatically stimulated, rather than inhibited, anthocyanin production, resulting in levels of accumulation beyond any of the tested elicitor combinations. Hypotheses for the observed influence of ibuprofen in this system are discussed.

Effects of exogenous methyl jasmonate in elicited anthocyanin-producing cell cultures of ohelo ( Vaccinium phalae )

In vitro- and ex vitro-rooted microcuttings of Acer rubrum L. ‘Red Sunset’, Betula nigra L., and Malux x- domestica Borkh ‘McIntosh’ were distinguished by several important anatomical and morphological properties which continued to regulate both root system and whole plant quality in later stages of production. In vitro microcuttings formed adventitious roots in greater number and more quickly than ex vitro microcuttings. Roots produced in vitro were characterized by extremely enlarged cortical cells and, consequently, had a much greater diameter than ex vitro roots. However, the vascular system of in vitro roots was underdeveloped (primary vascular tissues only) as compared to ex vitro roots, which produced vascular cambium and secondary growth during the same early stage of production. At least 50% of the post-transplant in vitro adventitious roots either died immediately, or temporarily persisted during acclimatization without producing any further growth. For the surviving in vitro-produced roots, the cortex partially collapsed after transplant, and new root extensions with ex vitro-like structure were produced. Only then did the in vitro portion of the root begin to form secondary vascular tissues. Shoots from in vitro treatments continued to grow vigorously during adventitious root initiation and during acclimatization, so that the plants were significantly taller and had a greater shoot area than those receiving comparable ex vitro rooting treatment. In vitro rooting led to a horizontal root morphology which continued to distinguish these treatments from ex vitro rooted plants during later stages of production, when anatomical differences in the roots could no longer be detected.

M. A. L. Smith

Papers

Automation and environmental control in plant tissue culture

Vessel type, closure, and explant orientation influence in vitro performance of five woody species

Vessels, gels, liquid media, and support systems

Effects of exogenous methyl jasmonate in elicited anthocyanin-producing cell cultures of ohelo ( Vaccinium phalae )

The effects of in vitro and ex vitro root initiation on subsequent microcutting root quality in three woody plants