Environmental Control of Flowering of Boronia megastigma (Rutaceae) and Hypocalymma angustifolium (Myrtaceae)

1994 ◽  
Vol 42 (2) ◽  
pp. 219 ◽  
Author(s):  
JS Day ◽  
BR Loveys ◽  
D Aspinall

The flowering responses of Boronia megastigma Nees (Rutacae) and Hypocalymma angustifolium Endl. (Myrtaceae) to different photoperiod and temperature regimes were similar despite the fact that these species are from different families. No flowers reached anthesis in a temperature regime of 25°C day/17°C night but flowering of both species occurred in a cool temperatures (17°C day/9°C night). Photoperiod had no effect on flowering at the temperatures tested. Ten weeks of cool temperatures (17°C day/9°C night) were required for a maximum number of flowers to reach anthesis on H. angustifolium plants whereas B. megastigma plants required 15 weeks. Flower development in both species was inhibited by a large difference between day and night temperature (21°C day/5°C night) and promoted if the day/night difference was reversed (9°C day/17°C night). The temperature of the aerial parts of the plant controlled flowering, whereas vegetative growth was controlled by root temperature. Therefore, while a reduction in vegetative growth naturally coincides with the production of flowers, these events are not necessarily linked.

1985 ◽  
Vol 3 (1) ◽  
pp. 25-27
Author(s):  
Carol Daggett ◽  
Gerald L. Klingaman

Ten woody plant species were rooted during the summer with half of each species overwintered at 4°C (40°F) and half at 18°C (65°F) minimum night temperature. Half of the plants in each temperature regime received long day conditions while half received short day conditions. By May 1 all species except Snow azalea (Rhododendron obtusum ‘Snow’), Emerald'n Gold euonymus (Euonymus fortunei ‘Emerald 'n Gold’), and deutzia (Deutzia gracilis) had greater dry weights with the 18°C (65°F) long day regime. Deutzia was heavier under the 4°C (40°F) regime with no difference between photoperiod treatments. At 4°C (40°F) only Judd viburnum (Viburnum x juddii) was heavier with the long day regime. Plants grown until June 1, after two flushes of vegetative growth, showed less overwintering treatment effect, but Hetzi holly (Ilex crenata ‘Hetzi’), blue rug juniper (Juniperus horizontalis ‘Wiltoni’), crapemyrtle (Lagerstroemia indica ‘Centennial’), and Judd viburnum (Viburnum x juddii) were larger when grown under the 18°C (65°F) long day regime.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1074c-1074
Author(s):  
Richard J. McAvoy

Poinsettias, Euphorbia pulcherrima Willd. cvs Lilo and Diva Starlight, were exposed to either warm day-cool night or cool day-warm night greenhouse temperature regimes. Day time temperatures were imposed between 900 to 1600 HR. Within each temperature regime, poinsettias were grown single stem or pinched and drenched with either 0.04 or 0.08 mg a.i. uniconazole per 1.6 1 pot or grown as untreated controls. Light levels (PAR) and potting medium and plant canopy temperatures were continuously monitored.Over the course of the study, the day-night temperature differential (DIF), in the plant canopy, averaged 4.2C in the warm day regime and -1.4C in the cool day regime. The average daily temperature was lower (16.9C) in the warm day regime than in the cool day regime (18.7C).DIF treatment significantly affected final leaf area, leaf and total plant dry weight, leaf area ratio and specific leaf weight, The DIF treatment by cultivar interaction was significant for final poinsettia leaf area, stem, leaf and total plant dry weight, break number and average break length. Uniconazole significantly affected final plant height, stem and total plant dry weight, break number, average break length and specific leaf weight. Uniconazole by DIF treatment effects were not significant,


Weed Science ◽  
1996 ◽  
Vol 44 (1) ◽  
pp. 63-67
Author(s):  
Robert E. Blackshaw

Vegetative growth response of round-leaved mallow to various day/night temperature regimes was studied under controlled-environment conditions to predict its potential geographic distribution and to develop an effective control program. Round-leaved mallow dry matter production was greatest with day temperatures of 18 to 26 C. Dry matter accumulation was reduced by a night temperature of 6 C but was minimally affected by night temperatures ranging from 12 to 24 C. Regression analysis predicted minimal vegetative growth at mean daily temperatures below 8 C and above 30 C, with optimum growth at 20 C. Partitioning of round-leaved mallow biomass in leaves, stems, and roots was affected by temperature. Maximum leaf weight ratio occurred at low temperatures, 10 C day and 6 C night. Stem weight ratio was greatest at a day temperature of 26 C, with night temperature having little effect. Maximum root biomass occurred with a day temperature of 18 C. Results are discussed in terms of environmental conditions that allow round-leaved mallow to be an effective competitor with crops and potential approaches for its control.


Agronomy ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 173 ◽  
Author(s):  
Ya Liu ◽  
Xiuxia Ren ◽  
Hai Jeong ◽  
Hao Wei ◽  
Byoung Jeong

Adenophora triphylla (Thunb.) A.DC., three-leaf lady bell, is an important medicinal plant used against cancers and obesity. It has been well-established that the temperature regime affects plant growth and development in many ways. However, there is no study available correlating the growth of A. triphylla seedlings with different day and night temperature regimes. In order to find an optimal temperature regime, growth and physiology were investigated in A. triphylla plug seedlings grown in environment-controlled chambers at different day and night temperatures: 20/20 °C (day/night) (TA), 25/15 °C (TB), and 20/15 °C (TC). The seedlings in plug trays were grown under a light intensity of 150 μmol·m−2·s−1 PPFD (photosynthetic photon flux density) provided by white LEDs, a 70% relative humidity, and a 16 h (day)/8 h (night) photoperiod for six weeks. The results showed that the stem diameter, number of roots, and biomass were significantly larger for seedlings in TB than those in TA or TC. Moreover, the contents of total flavonoid, total phenol, and soluble sugar in seedlings grown in TB were markedly higher than those in seedlings in the other two treatments. Soluble protein content was the lowest in seedlings in TC, while starch content was the lowest in seedlings grown in TA. Furthermore, seedlings grown in TB showed significantly lower activities of antioxidant enzymes such as superoxide dismutase, catalase, ascorbate peroxidase, and guaiacol peroxidase. Native PAGE (polyacrylamide gel electrophoresis) analysis further proved low activities of antioxidant isozymes in TB treatment. Meanwhile, the lowest content of hydrogen peroxide was observed in seedlings grown in TB. In conclusion, the results suggested that the 25/15 °C (day/night) temperature regime is the most suitable for the growth and physiological development of A. triphylla seedlings.


1988 ◽  
Vol 36 (3) ◽  
pp. 201-208 ◽  
Author(s):  
J.C. Bakker ◽  
J.A.M. van Uffelen

Growth and yield of Oct.-sown Capsicum annuum, cv. Delphin, were investigated in a greenhouse under 12 day/night temperature regimes (16/15 degrees , 16/21 degrees , 20/12 degrees , 20/15 degrees , 20/18 degrees , 20/21 degrees , 24/12 degrees , 24/15 degrees , 24/18 degrees , 24/21 degrees , 28/15 degrees and 28/21 degrees C) applied during the early post-planting period (early Dec. to mid-Apr.). Fresh weight and leaf number were significantly correlated with 24-h mean temperature, but no significant effect of the day/night temperature amplitude was found. Plant height, leaf area and the leaf-area:length ratio were significantly correlated with 24-h mean temperature and with day/night temperature amplitude. The optimum 24-h mean temperature for vegetative growth was between 21 and 23 degrees . Yields of total and class 1 fruits (kg/msuperscript 2) and numbers of class 1 fruits were greatest at a 24-h mean temperature of 21-21.5 degrees . Raising the 24-h mean air temperature within the range 16.3 to 23.8 degrees significantly reduced the mean fruit weight of class 1 fruits. The day/night temperature amplitude had a significant positive effect on these variables. The effect of the day/night temperature amplitude on vegetative growth and on yield was of minor importance compared with the effect of the 24-h mean temperature. (Abstract retrieved from CAB Abstracts by CABI’s permission)


Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1367
Author(s):  
Valentina Obradović ◽  
Jurislav Babić ◽  
Verica Dragović-Uzelac ◽  
Antun Jozinović ◽  
Đurđica Ačkar ◽  
...  

The objective of this research was to investigate the potentiality of carrot powder (CP) utilization at levels 4, 6, or 8% as ingredient of corn snacks and evaluation of the extrusion influence on functionally important ingredients such as carotenoids (color), polyphenols, fiber, fat, and antioxidant activity. The influence of ascorbic acid (AA) as an external source at levels 0.5 and 1% on this particular extrusion was also investigated. A single-screw extruder at two temperature regimes (135/170/170 °C (E1) and 100/150/150 °C (E2)) carried out extrusion. The E1 temperature regime acted favorably on total polyphenol content and crude fiber, but fat preferred the E2 regime. Extrusion, especially the E1 temperature regime, increased the extractability of carotenoids. Ascorbic acid degraded during extrusion, but it still provided protection to carotenoids and color attributes of extrudates. Snacks with increased nutritional and functional value due to carrot powder addition were successfully produced, which is a starting point for production of a new type of extruded snacks.


2013 ◽  
Vol 54 (5) ◽  
pp. 405-411 ◽  
Author(s):  
Juniel Galido Lucidos ◽  
Kwang Bok Ryu ◽  
Adnan Younis ◽  
Chang-Kil Kim ◽  
Yoon-Jung Hwang ◽  
...  

1979 ◽  
Vol 59 (2) ◽  
pp. 469-473 ◽  
Author(s):  
R. G. INGRATTA ◽  
G. R. STEPHENSON ◽  
C. M. SWITZER

Optimum top growth of annual bluegrass (Pao annua L.) and Kentucky bluegrass (Poa pratensis L.) was obtained at 24/12 °C day/night temperature regime in controlled environment studies. The tolerance of seedling Kentucky bluegrass to linuron [3-(3,4-dichlorophenyl)-1)methylurea] appeared to be greatest at this temperature regime when photoperiods were 16 h in length. A granular formulation of linuron gave excellent control of annual bluegrass in Kentucky bluegrass turf at 6.7 kg/ha when applied postemergence. At this rate, all culitivars of Kentucky bluegrass tested, with the exception of Fylking, were tolerant to linuron as a granular formulation. After application of linuron at 3.4–6.7 kg/ha, phytotoxic residues remained in the soil at sufficient levels to injure seedling Kentucky bluegrass for up to 3 mo.


2021 ◽  
Vol 11 ◽  
Author(s):  
Sarah Muszynski ◽  
Florian Maurer ◽  
Sina Henjes ◽  
Marcus A. Horn ◽  
Matthias Noll

Environmental fluctuations are a common occurrence in an ecosystem, which have an impact on organismic diversity and associated ecosystem services. The aim of this study was to investigate how a natural and a species richness-reduced wood decaying community diversity were capable of decomposing Fagus sylvatica dead wood under a constant and a fluctuating temperature regime. Therefore, microcosms with both diversity levels (natural and species richness-reduced) were prepared and incubated for 8 weeks under both temperature regimes. Relative wood mass loss, wood pH, carbon dioxide, and methane emissions, as well as fungal and bacterial community compositions in terms of Simpson‘s diversity, richness and evenness were investigated. Community interaction patterns and co-occurrence networks were calculated. Community composition was affected by temperature regime and natural diversity caused significantly higher mass loss than richness-reduced diversity. In contrast, richness-reduced diversity increased wood pH. The bacterial community composition was less affected by richness reduction and temperature regimes than the fungal community composition. Microbial interaction patterns showed more mutual exclusions in richness-reduced compared to natural diversity as the reduction mainly reduced abundant fungal species and disintegrated previous interaction patterns. Microbial communities reassembled in richness-reduced diversity with a focus on nitrate reducing and dinitrogen-fixing bacteria as connectors in the network, indicating their high relevance to reestablish ecosystem functions. Therefore, a stochastic richness reduction was followed by functional trait based reassembly to recover previous ecosystem productivity.


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