Stress chilling

In addition to the induction of anthocyanin biosynthesis, chilling stress has also been shown to promote the formation of colorless flavonoids. Cold treatments (and drought stress) caused increases in levels of (—)-epicatechin and hyperoside (quercetin 3-galactoside) in two species of hawthorn, Crataegus laevigata and C. monogyna. Such treatments also enhanced the antioxidant capacity of the shoot extracts, and this may be the primary function of these cold-inducible flavonoids. 

Kratsch HA., Wise RR. The ultrastructure of chilling stress. Plant, Cell Environment 2000 23(4) 337-350. 

Effect of Brassinolide on Growth Recovery of Maize Seedlings after Chilling Stress... 

Figure 1. Effect of brassinolide on the growth (A) and cotyledon-chlorophyll content (B) of cucumber seedlings subjected to chilling stress, measured 5 days after chiding treatment. (Ochi, N. and Katsumi, M. unpublished)...

Adnan, S., L. Susan, and D. Weiss. 1998. Isolation and characterization of a heat-induced gene, hcit2, encoding a novel 16.5 kDa protein expression coincides with heat-induced tolerance to chilling stress. Plant Mol. Biol. 36 935-939. 

Guo, S.J., H.Y Zhou, X.S. Zhang, X.G. Li, and Q.W. Meng. 2007. Overexpression of CaHSP26 in transgenic tobacco alleviates photoinhibition of PSII and PSI during chilling stress under low irradiance. J. Plant Physiol. 164 126-136. 

Lee, D.H., and C.B. Lee. 2000. Chilling stress-induced changes of antioxidant enzymes in the leaves of cucumber in gel enzyme activity assays. Plant Sci. 159 75-85. 

Following chilling stress at 5 C for 48 hours, only BR102 exhibited significant decreases (51%) in net photosynthetic rates per unit leaf area (Table 1). The 25% decrease observed in this parameter in YF8-4... 

Table 1. Photosynthetic rates (Pnet) per unit leaf area (umol m s ) and per unit chlorophyll (mgC02 g xhl s ), stomatal and mesophyll conductances (cm s ), and internal COj concentrations (ppm) for BR102 and YF8-4 grown at 23/ll C and following chilling stress and recovery. Values in parentheses represent p-values calculated in tests of significance between mean values of a parameter for stressed and unstressed plants.

Table 2. Initial (Fo) and maximum (Fmax) fluorescence levels per ug chlorophyll a, Fvm/Fo, steady state fluorescence levels (F ), qQ, and qN for BR102 and YF8-4 subjected to chilling stress and recovery. Values in parentheses represent the parameter value for control plants. The results of significance tests between control and stressed plants are reported as p-values.

In this paper, we report that the Chi—protein complexes are disintegrated and the mechanisms of regulation of the excitation energy distribution can be perturbed in leaves of cucumber submitted to chilling stress conditions. 

Table 1. Specific activities (pmol [mg protein] h ) of enzymes involved in scavenging photoreduced species of dioxygen in Zea mays and Zea diploperennis leaves, assayed at 19 and The plants had not been chill stressed. Mean values SE of triplicate samples are given. Figures in parenthesis indicate the percentage reduction in enzyme specific activity at 5 C relative to 19 C.

To avoid error introduced by label contained in the contaminating polypeptides comigrating with the dimer, only the oligomer and monomer were compared in Fig. 4. Consistent with the results shown in Fig. 1, chill stress results in an increase of lysine incorporation into the monomer relative to the oligomer. Recovery is complete after 24-48 h. The chill-induced shift is not as dramatic as shown in the octyl-glucoside/SDS system, perhaps because the dimer has been omitted. 

The results in Figures 1 and 5 show that chilling in the light alters the relative incorporation of label into the pigment-protein complexes known to comprise LHC 11. While the 31 kDa chill-induced polypeptide described earlier disappears with 1 h of recovery at non-chilling temperatures, the pattern of label incorporation does not return to control levels for 24 h. This time course more closely parallels the recovery seen in other parameters altered by chill stress. 

Chilling Stress and Active-Oxygen Enzymes in Zea mays and Zea diploperennis 683... 

Nonfreezing low temperature stress on phenolics metabolism has been considered in several papers. These studies have shown that the phenolic metabolism is enhanced under chill stress and that the behavior of the same metabolism is further dependent on the storage temperature. There is a low critical temperature below which an increase of phenolic metabolism is stimulated, and this temperature is related to the threshold temperature at which chilling injury is also induced. It has been also observed that the low temperarnre effect involves a cold-induced stimulatimi of the phenylalanine ammonia-lyase activity (PAL, EC 4.3.1.5) as well as other enzymes important in the... 

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