scholarly journals Gene Expression Analysis a Cold Responsive Gene from Poncirus trifoliata during Acclimation and Deacclimation

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 862C-862
Author(s):  
Adriana Robbins ◽  
Ying Jia ◽  
Eliezer Louzada*
Keyword(s):  
Low Temperature ◽  
Expression Analysis ◽  
Low Temperatures ◽  
Cold Hardiness ◽  
Poncirus Trifoliata ◽  
Trifoliate Orange ◽  
Rt Pcr ◽  
Reading Frame ◽  
Transcript Stability ◽  
Cold Hardy

In Texas, the freezes of 1951 and 1962 together killed 125,000 acres of citrus trees and the freeze of 1983 killed 40,000 acres. The low temperature is one of the most important abiotic stresses to be understood and manipulated molecularly. Cold hardiness is found in the deciduous citrus relative, trifoliate orange, which can withstand temperatures as low as -26 °C when it is cold acclimated. Exposure of the cold hardy trifoliate orange plants to temperature from 28 °C to -5 °C enabled us to isolate and characterize one novel citrus low temperature gene (clt) with two transcripts, called clt-a and clt-b from leaves and twigs. Clt-a was produced when plants were subjected to low temperatures (starting at 10 °C), while cltb was constitutively expressed. Both clt-a and clt-b have the same open reading frame of 165 nucleotides and encodes a small protein of 54 amino acid. However, clt-a has an additional 98 bp nucleotides at the 3'-untranslated region (UTR), which is absent in clt-b. Expression analysis using relative quantitative RT-PCR demonstrated that clt-a is expressed exclusively at low temperatures, while clt-b is expressed constitutively (expression verified from 2 °C to -5 °C). In the process of deacclimation from -1 °C to 28 °C, the clt-a transcript degraded dramatically after 2 °C and was completely absent at 28 °C, while the clt-b transcript remain stable. When the acclimated plant was taken from -1 °C to room temperature, the clt-a gene degraded within 2 hours. Moreover, when acclimated plant was continuously exposed at -1 °C for 20 days, both transcripts clt-a and clt-b remained stable. Involvement of alternative splicing in transcript stability will be discussed.

Flower cold hardiness: a potential determinant of the flowering sequence exhibited by bog ericads

1979 ◽  
Vol 57 (9) ◽  
pp. 997-999 ◽  
Author(s):  
R. J. Reader
Keyword(s):  
Low Temperatures ◽  
Cold Hardiness ◽  
Vaccinium Macrocarpon ◽  
Southern Ontario ◽  
Air Temperatures ◽  
Insect Pollinators ◽  
Cold Hardy ◽  
Vaccinium Myrtilloides ◽  
Potential Determinant ◽  
Ledum Groenlandicum

In laboratory freezing trials, cold hardiness of six types of bog ericad flowers differed significantly (i.e., Chamaedaphne calyculata > Andromeda glaucophylla > Kalmia polifolia > Vaccinium myrtilloides > Ledum groenlandicum > Vaccinium macrocarpon) at air temperatures between −4 and −10 °C but not at temperatures above −2 °C. At the Luther Marsh bog in southern Ontario, low temperatures (−3 to −7 °C) would select against May flowering by the least cold hardy ericads. Availability of pollinators, on the other hand, would encourage May flowering by the most cold hardy species. Presumably, competition for insect pollinators has promoted the diversification of bog ericad flowering peaks, while air temperature, in conjunction with flower cold hardiness, determined the order in which flowering peaks were reached.

scholarly journals Identification and characterization of a circadian clock-associated pseudo-response regulator 7 gene from trifoliate orange

2020 ◽  
Vol 48 (1) ◽  
pp. 128-139
Author(s):  
Yu-E DING ◽  
Wenkai HUANG ◽  
Bo SHU ◽  
Ying-Ning ZOU ◽  
Qiang-Sheng WU ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Response Regulator ◽  
Poncirus Trifoliata ◽  
Pcr Analysis ◽  
Trifoliate Orange ◽  
Drought Treatment ◽  
Reading Frame ◽  
Rhythmic Expression ◽  
Pseudo Response Regulator ◽  
Main Component

Circadian clock is usually involved in many physiological processes of plants, including responses to abiotic stress, whilst pseudo-response regulator 7 (PRR7) gene is the main component of the circadian clock. In this study, the cDNA of the PRR7 gene was obtained from trifoliate orange (Poncirus trifoliata). Based on the sequence analysis, the PtPRR7 gene had an open reading frame of 2343 bp, encoded 780 amino acids, and contained proteins of the REC and CCT domains. Subcellular localization indicated that PtPRR7 was mainly localized in the nucleus and a small amount of cytoplasm. qRT-PCR analysis revealed the highest expression level of PtPRR7 in roots than in both shoots and leaves. The PtPRR7 gene during 24 hours of soil water deficit exhibited a circadian rhythmic expression pattern: the expression peak at 9:00 am in leaves and at 21:00 pm in roots. Drought treatment affected PtPRR7 gene expression. Such data provide important references for understanding the characteristics of PtPRR7 gene in citrus plants.

scholarly journals Mycorrhizal efficacy of trifoliate orange seedlings on alleviating temperature stress

2011 ◽  
Vol 57 (No. 10) ◽  
pp. 459-464 ◽  
Author(s):  
Q.S. Wu
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Protein Content ◽  
Temperature Stress ◽  
Soluble Protein ◽  
Mycorrhizal Colonization ◽  
Poncirus Trifoliata ◽  
Trifoliate Orange ◽  
Soluble Protein Content ◽  
Entry Points

Citrus plants often suffer from temperature stress, which seriously inhibits tree growth and even results in tree death. The present experiment was conducted to evaluate the effects of Glomus mosseae on growth, root morphology, superoxide dismutase (SOD) and catalase (CAT) activities, and soluble protein content of trifoliate orange (Poncirus trifoliata) seedlings at low (15°C), optimum (25°C) and high (35°C) temperatures. Sixty-eight days after temperature stresses, mycorrhizal colonization and number of both entry points and vesicles were significantly inhibited by low or high temperature. Mycorrhizal seedlings recorded significantly higher growth characteristics than non-mycorrhizal seedlings at both optimum and high temperatures, but the beneficial effects were almost lost at low temperature. Generally, mycorrhizal seedlings presented notably higher root traits (projected area, surface area, number of forks and volume) than non-mycorrhizal seedlings regardless of temperature levels. Mycorrhizal colonization significantly increased SOD and CAT activities and soluble protein content at high temperature, increased only SOD activity at optimum temperature, and decreased only soluble protein content at low temperature. It suggests that mycorrhizal alleviation of temperature stress in trifoliate orange seedlings was at high temperature, but the alleviation was obviously weakened at low temperature.

Cold-Hardiness, Habitat and Winter Survival of Some Orchard Arthropods in Nova Scotia

1964 ◽  
Vol 96 (4) ◽  
pp. 617-625 ◽  
Author(s):  
A. W. MacPhee
Keyword(s):  
Nova Scotia ◽  
Air Temperature ◽  
Low Temperatures ◽  
Cold Hardiness ◽  
Winter Survival ◽  
Kings County ◽  
Winter Conditions ◽  
Cold Hardy

AbstractIn Kings County, Nova Scotia, low temperatures in the coldest nights of winter can differ by as much as 10°F. from one area to another. This has an important bearing on winter survival of some arthropods. Overwintering sites of orchard arthropods range from exposed situations which remain at air temperature to well protected ones on the ground where temperatures rarely go below 20°F. The cold-hardiness of each of 24 species of arthropods was measured: seven were sufficiently cold-hardy to survive any winter conditions in Nova Scotia, five were less cold-hardy but overwinter in well protected sites and twelve had marginal cold-hardiness, their mortality varying with the winter and the locality.

THE EFFECT OF LONG EXPOSURE TO LOW TEMPERATURES ON THE COLD HARDINESS OF SPROUTING WHEAT IN THE DARK

1985 ◽  
Vol 65 (4) ◽  
pp. 893-900 ◽  
Author(s):  
D. W. A. ROBERTS
Keyword(s):  
Triticum Aestivum ◽  
Low Temperatures ◽  
Cold Hardiness ◽  
Triticum Aestivum L ◽  
Late Winter ◽  
Initial Increase ◽  
Winter Mortality ◽  
Canadian Prairies ◽  
Northern Regions ◽  
Cold Hardy

Nine cultivars of common wheat (Triticum aestivum L.) ranging from very cold hardy to tender were sprouted in vermiculite at 0.5–1.0 °C for 7 wk in the dark and then placed at 0.5 °C, −2.5 °C, −5 °C, −7.5 °C, or −10 °C for up to 20 wk. Plants held at 0.5 °C progressively lost hardiness. Little change occurred in the hardiness of plants moved to −2.5 °C. There was apparently a small initial increase in hardiness after transfer to −5 °C or −7.5 °C followed by a decline in hardiness. Plants transferred to −10 °C lost hardiness progressively after transfer. These results suggest that part of the reason for late-winter mortality of winter wheats in northern regions of the Canadian prairies is damage from long exposures to temperatures only slightly lower than −5 °C. This damage is manifested by higher LT50 values or lower cold hardiness in late winter and early spring.Key words: Triticum aestivum L., cold hardiness, winter survival

SURVIVAL OF PUPAE OF HELIOTHIS VIRESCENS AND HELIOTHIS ZEA (LEPIDOPTERA: NOCTUIDAE) AT LOW TEMPERATURES

1982 ◽  
Vol 114 (4) ◽  
pp. 289-301 ◽  
Author(s):  
Joseph E. Eger ◽  
John A. Witz ◽  
Albert W. Hartstack ◽  
Winfield L. Sterling
Keyword(s):  
Low Temperature ◽  
Exposure Time ◽  
Predictive Models ◽  
Low Temperatures ◽  
Heliothis Virescens ◽  
Cold Hardiness ◽  
Heliothis Zea ◽  
Geographic Locations ◽  
Lepidoptera Noctuidae

AbstractMortality of diapausing and non-diapausing pupae of Heliothis virescens (Fabricius) and H. zea (Boddie) at low temperatures was assessed in the laboratory. Comparison of the exposure time necessary to induce 50% mortality (LT50) indicated that survival of diapausing pupae was significantly higher than that of non-diapausing pupae. Similar comparisons showed no consistent significant differences in mortality of pupae from different geographic locations within Texas or in pupae preconditioned in several different ways. One exception was the response of pupae of H. virescens preconditioned to varying temperatures. This type of preconditioning appeared to increase the cold-hardiness of pupae at subfreezing temperatures. Contact moisture significantly decreased LT50 values of pupae of both species at sub-zero temperatures. Predictive models for low temperature mortality were developed for dry, diapausing pupae.

scholarly journals 334 Seasonal Characterization of the Phenolic Layer Beneath Floral Buds of Rhododendron spp.

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 500E-500
Author(s):  
Michelle R. Salemi ◽  
James D. Scott ◽  
Linda Chalker-Scott
Keyword(s):  
Thermal Analysis ◽  
Low Temperature ◽  
Fluorescence Microscopy ◽  
Preliminary Analysis ◽  
Cold Hardiness ◽  
Floral Buds ◽  
Dormant Season ◽  
Cold Hardy ◽  
The Relationship

It has been previously shown that dormant, cold-hardy floral buds of Azalea possess layers of highly lignified and suberized cells below the bud axis and beneath each bud scale. Two species of deciduous Azalea were analyzed bi-weekly using differental thermal analysis (DTA) throughout their dormant season to determine the development of cold hardiness as denoted by low temperature exotherms (LTEs). Other buds collected at the same time were observed using fluorescence microscopy to document the relationship between the development of the barrier and the onset of cold hardiness. Preliminary analysis showed when buds were maximally cold hardy the barrier was most intact, and as buds began to lose hardiness, the layer started to degrade. These results suggest that in fact this layer of cells does act as the long-proposed bud barrier. In a comparison between the species, the hardier species (R. japonicum) was found to have a denser layer of phenolic-rich cells compared to buds of the less hardy species (R. occidentale). This finding further supports the relationship between the layer of cells and the existence of cold hardiness in bud tissues.

scholarly journals The Interaction of Photoperiod and Temperature on Cold Hardiness and the Accumulation of Soluble Sugars in Two Cultivars of Southern Magnolia (Magnolia grandiflora L.)

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 848F-848
Author(s):  
C.L. Haynes ◽  
O.M. Lindstrom ◽  
M.A. Dirr
Keyword(s):  
Low Temperature ◽  
Cold Acclimation ◽  
Low Temperatures ◽  
Cold Hardiness ◽  
Sugar Content ◽  
Soluble Sugar ◽  
Soluble Sugars ◽  
Total Soluble Sugars ◽  
Magnolia Grandiflora ◽  
Temperature Interaction

Decreasing photoperiods and decreasing temperatures induce cold acclimation and the accumulation of soluble sugars in many plants. Two cultivars of southern magnolia differing in cold hardiness and acclimation patterns, were monitored to determine photoperiod × temperature interaction on cold hardiness and soluble sugar content. Cold hardiness increased with low temperatures and short photoperiods. Total soluble sugars, sucrose, and raffinose consistently increased in the leaves and stems of both cultivars in response primarily to low temperature. `Little Gem' was less responsive to photoperiod than `Claudia Wannamaker'

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