The stress level in a plant may be directly associated with the intensity of the Kautsky effect (the sudden increase in fluorescence emission by chlorophyll following a dark adaptation). The decrease in photosynthetic efficiency, linked with the rate of photochemistry of plants under stress, provides a definitive signature (graphical pattern) that can be quantified and monitored, even for plants that have no visible stress symptoms. Using a prototype GrowScanner®, signature differences in plants under nitrogen and water stress, as compared with plants not under stress, could be detected and measured. Returning stressed plants to a nonstressed condition returned the stress signatures to that of control plants not under stress. Development of the technology may provide a relatively quick, presymptomatic methodology for detecting plant stress without sacrificing plant tissue.
Hussein Al-Amier, Robert Lussier, Ming Coler, Margaret Stoltzman and Lyle Craker
Hussein Al-Amier, Khaled A. Nasr, Lorna Lück and Lyle E. Craker
Black cohosh [Actaea racemosa L.; syn. Cimicifuga racemosa (L.) Nutt.] is a medicinal plant native to America and the woodlands of eastern North America. The roots and rhizomes of black cohosh, used by Native Americans to ease childbirth and treat menstrual cramps, rheumatism, headaches, coughs, asthma, and snakebites, are currently popular as an herbal remedy in the United States and Europe for the relief of discomfort associated with menopause. To determine chemical variation among populations of this perennial plant, root samples from 33 locations within the natural range of the species, ranging from Massachusetts to South Carolina and west to Missouri and Tennessee, were collected and chemically analyzed by HPLC-PDA using a C-18 reversed phase column (Phenomenex) for separation of the chemical constituents. The constituents were identified by comparison with commercial standards, including actein, methyl-beta-arabinopyranoside, caffeic acid, cimicifugoside, cimicifugoside H1, cimiracemoside A, 26 deoxyactein, ferulic acid, isoferulic acid, kaempferol, formononetin, and others. Chemically, an extract of the root and rhizome is known to contain at least three major natural product groups: cycloartenal-type triterpenes, phenolics, and flavonoids. Chemical constituents, especially formononetin, varied among the populations.