Chemical Regulation of Plastid Development. I. Inhibition of Chlorophyll Biosynthesis in Detached Pumpkin Cotyledons by CPTA. A Pigment and Ultrastructual Study

1974 ◽  
Vol 1 (1) ◽  
pp. 119 ◽  
Author(s):  
DJ Simpson ◽  
CO Chichester ◽  
TH Lee

The effects of 2-(4-chlorophenylthio)ethyldiethylammonium chloride (CPTA) on chlorophyll accumulation, carotenoid biosynthesis and plastid ultrastructure were examined in expanding excised pumpkin cotyledons. CPTA in the dark caused an increased synthesis of non-photoconvertible protochlorophyll but had no effect on the ultrastructure of the starch-containing plastids. In the light, CPTA was a powerful inhibitor of chlorophyll synthesis in greening cotyledons, especially at high light intensity, and induced the accumulation of lycopene. When applied to the greened cotyledons, CPTA caused the transformation of the chloroplasts to chromoplast-like organelles containing osmiophilic globules and lycopene crystalloids. Two other structurally similar compounds,diethyl[4-{3'-(4"-methylphenyl)-3-oxoprop-2' -enyl}phenoxyethyl]ammonium chloride (SK&F 13831) and (2-chloroethyl)trimethylammonium chloride (chlormequat), also caused lycopene accumulation and inhibited chlorophyll synthesis. It is possible that CPTA can induce the formation of chromoplasts from proplastids and chloroplasts in tissue that does not normally contain such organelles.

Author(s):  
Tatyana V. Samovich ◽  
Ruslan G. Goncharik ◽  
Elizaveta I. Pechenkina ◽  
Yauhen V. Viazau ◽  
Nikolay V. Kozel

It was established that nitrogen deficiency initiated at the resting phase of Haematococcus pluvialis (H. pluvialis) is not an effective stress factor in combination with high light intensity to induce the accumulation of astaxanthin in algae cells. The amounts of astaxanthin in H. pluvialis cells in the absence of nitrogen were lower compared to those when complete Rudic medium was used, regardless of the light intensity. This fact indicates the need for a certain amount of nitrogen in the medium for the functioning of the astaxanthin synthesis system. In addition, the low yield of astaxanthin in the experimental variants cultivated on incomplete Rudic medium is associated with the insufficient amount of nitrogen for its biosynthesis and also with a decrease in the expression level of the PSY gene encoding a key enzyme of the carotenoid biosynthesis chain – phytoene synthase.


2009 ◽  
Vol 34 (12) ◽  
pp. 2196-2201 ◽  
Author(s):  
Xue-Li QI ◽  
Lin HU ◽  
Hai-Bin DONG ◽  
Lei ZHANG ◽  
Gen-Song WANG ◽  
...  

2017 ◽  
Vol 129 (2) ◽  
pp. 209-221 ◽  
Author(s):  
Amritpal S. Singh ◽  
A. Maxwell P. Jones ◽  
Mukund R. Shukla ◽  
Praveen K. Saxena

Ethology ◽  
2012 ◽  
Vol 118 (4) ◽  
pp. 341-350 ◽  
Author(s):  
Esteban Fernández-Juricic ◽  
Marcella Deisher ◽  
Amy C. Stark ◽  
Jacquelyn Randolet

Weed Science ◽  
1970 ◽  
Vol 18 (4) ◽  
pp. 509-514 ◽  
Author(s):  
Lafayette Thompson ◽  
F. W. Slife ◽  
H. S. Butler

Corn(Zea maysL.) in the two to three-leaf stage grown 18 to 21 days in a growth chamber under cold, wet conditions was injured by postemergence application of 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) plus emulsifiable phytobland oil. Injury was most severe when these plants were kept under cold, wet conditions for 48 hr after the herbicidal spray was applied, followed by exposure to high light intensity and high temperature. Under these growth chamber conditions, approximately 50% of the atrazine-treated plants died. Since wet foliage before and after application increased foliar penetration and low temperature decreased the rate of detoxication to peptide conjugates, atrazine accumulated under cold, wet conditions. This accumulation of foliarly-absorbed atrazine and the “weakened” conditions of the plants grown under the stress conditions is believed to be responsible for the injury to corn. Hydroxylation and the dihydroxybenzoxazin-3-one content in the roots were reduced at low temperature, but it is unlikely that this contributed to the death of the corn.


2017 ◽  
Vol 14 (24) ◽  
pp. 5693-5704 ◽  
Author(s):  
Gabriella M. Weiss ◽  
Eva Y. Pfannerstill ◽  
Stefan Schouten ◽  
Jaap S. Sinninghe Damsté ◽  
Marcel T. J. van der Meer

Abstract. Over the last decade, hydrogen isotopes of long-chain alkenones have been shown to be a promising proxy for reconstructing paleo sea surface salinity due to a strong hydrogen isotope fractionation response to salinity across different environmental conditions. However, to date, the decoupling of the effects of alkalinity and salinity, parameters that co-vary in the surface ocean, on hydrogen isotope fractionation of alkenones has not been assessed. Furthermore, as the alkenone-producing haptophyte, Emiliania huxleyi, is known to grow in large blooms under high light intensities, the effect of salinity on hydrogen isotope fractionation under these high irradiances is important to constrain before using δDC37 to reconstruct paleosalinity. Batch cultures of the marine haptophyte E. huxleyi strain CCMP 1516 were grown to investigate the hydrogen isotope fractionation response to salinity at high light intensity and independently assess the effects of salinity and alkalinity under low-light conditions. Our results suggest that alkalinity does not significantly influence hydrogen isotope fractionation of alkenones, but salinity does have a strong effect. Additionally, no significant difference was observed between the fractionation responses to salinity recorded in alkenones grown under both high- and low-light conditions. Comparison with previous studies suggests that the fractionation response to salinity in culture is similar under different environmental conditions, strengthening the use of hydrogen isotope fractionation as a paleosalinity proxy.


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