Glutinosone,a new antifungal sesquiterpene from Nicotiana glutinosa infected with tobacco mosaic virus

Glutinosone is an antifungal substance induced in leaves of Nicotiana glutinosa following infection with tobacco mosaic virus. From chemical, spectroscopic and biogenetic evidence it has been assigned structure (1).     

Conversion of p-coumaric acid to p-hydroxybenzoic acid by cell free extracts of potato tubers and Polyporus hispidus

The conversion of p-coumaric acid to p-hydroxybenzoic acid was demonstrated in vitro in both potato tuber and P. hispidus. The mechanism of the enzyme system is non-oxidative. This is the first report of a cell free system which is capable of converting a C₆-C₃ acid to the corresponding C₆-C₁ derivative from a fungus.     

Effect of darkness on isoperoxidases in tobacco tissue cultures

In order to study the effect of light on the tobacco tissue culture WR-132, 5 passages (10 days' growth per passage) of these cells were grown in darkness, and 3 passages were separately grown in intense light (16000 lx). All other growth conditions were the same. The resulting isoperoxidase patterns present in these cells and in their growth media were analyzed at 2-day intervals during this period and then compared with the isoperoxidase patterns of cells grown under dim light conditions (10 lx). A new cathodic isoperoxidase (C_n) appeared in the medium within 2 days after the cells were placed in the dark. C_n was present in all media of WR-132 cell cultures analyzed throughout the 5 passages grown in darkness. The fifth passage in darkness produced total cessation of growth (apparent death). C_n increased and new anodic isoperoxidases A_a, A_b, A_d and A_e appeared in the media as the cells approached death in darkness.     

Free and esterified carotenoids in green and red fruits of Capsicum annuum

Fully green and mature red fruits of the Yolo Wonder A variety of Capsicum annuum were analysed for their carotenoid content. The disappearance of chlorophyll was followed by an increased synthesis of carotenoids. Lutein was not detected in the red fruit in which capsanthin was the main carotenoid. It appeared as diester, monoester and free forms, while capsorubin occured as a diester only. Cryptocapsin was not esterified.     

Wavelength dependence of suppression of potato sprout growth by light

Abstract Light is used commercially to prevent the sprouts on seed potatoes from growing so long that they are knocked off at planting. We investigated the relationship between wavelength and growth inhibition, using a very long irradiation time of 23 d with a 12-h photoperiod. The inhibition showed a narrow peak of far-red activity centered on 707 nm, with a shoulder in the red whose size depended on the degree of inhibition chosen as standard, because the log photon-fluence rate/response lines were not parallel. There was also inhibitory activity in the blue (< 500 nm). In many respects the wavelength relationship resembled the action spectra for growth inhibition in dark-grown seedlings, but in the latter the red peak is, or quickly becomes, more pronounced than the far-red peak: this did not happen with potato sprouts. Blue light caused a positive phototropic response at similar or lower fluence rates. Greening became visible only at the highest fluence rates, between the two spectral regions inhibitory to growth. Broadband sources had much less inhibitory activity in the 650–750-nm region.     

Isolation of tomatine from cultured excised roots and callus tissues of tomato

Tomatine was present in cultured excised tomato roots but in lower concentrations than in seedling radicles of the same age. The alkaloid was not detected in 'spent' root medium. Newly-initiated callus cultures of hypocotyl, radicle and cotyledon origin produced roots, and tomatine was isolated from both roots and callus. Roots contained more tomatine than callus, but neither contained as much as the organ explants from which the cultures were initiated. The number of roots produced decreased with time, as did also the tomatine content of the callus tissues. After 447 days, when no organized structures were produced by callus cultures, tomatine was not detected. An established hypocotyl callus contained small amounts of tomatine when grown on certain nutrient media, but a chlorophyllous sub-isolate of this callus did not produce detectable quantities of the alkaloid. Tomatine was not detected in an established root callus isolate or in suspension cultures initiated from established, tomatine-containing hypocotyl callus.     

2-trans-ABA alcohol accumulation in the wilty tomato mutants flacca and sitiens

Abstract Two wilty tomato mutants, flacca and sitiens, fail to increase their endogenous ABA concentration in response to water stress. Instead, a compound accumulates which has been identified as 2-trans-ABA alcohol. Levels of this compound have been estimated for three wilty mutants and the control; both before and after water stress. When the compound was biosynthesized in the presence of ¹⁸O₂, one atom appeared to be incorporated into the primary alcohol group. The possible implications of this for the ABA biosynthetic pathway are discussed.     

Phylogenomic discovery of deleterious mutations facilitates hybrid potato breeding

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