Increase In Night Temperature Research Articles

Effect of Canopy Position on the Susceptibility of Kiwifruit (Actinidia deliciosa) Leaves on Vines in an Orchard Environment to Photoinhibition Throughout the Growing Season

Kiwifruit (Actinidia deliciosa (A. Chev) C.F. Liang & A.R. Ferguson) plants grown in an orchard were studied over several seasons to assess the impact of photoinhibition on the leaves using chlorophyll fluorescence and photosynthetic measurements. Leaves above were compared with those below the vine canopy. In addition, temperature and photon flux densities above and below the canopy were monitored. A gradient of sun to shade photosynthetic characteristics developed in leaves from above to below the canopy. There was a 10% higher Fv/Fm ratio in the shade leaves (0.810) but a 30% lower photosynthetic capacity and a 30% higher photon yield than in sun leaves. In addition, Fo and Fm were both higher (20-60%) in shade leaves. Little variation in Fv/Fm occurred throughout the growing season, except during spring, when Fv/Fm was about 0.4-0.5, especially in small, rapidly expanding leaves. Changes in Fv/Fm during spring were correlated with leaf diameter, indicating development of photosynthetic competence was an important factor in the rise in Fv/Fm. However, increasing night temperatures also correlated with the increase in Fv/Fm during spring.

Seedling Growth of Catawba Rhododendron. II. Photosynthesis and Carbohydrate Accumulation and Export

Catawba rhododendron (Rhododendron catawbiense Michx.) seedlings of two provenances, Johnston County, N.C. (35°45′N, 78°12′W, elevation = 67 m), and Yancey County, N.C. (35°45′N, 82°16′W, elevation = 1954 m), were grown in controlled-environment chambers for 18 weeks with days at 18, 22, 26, or 30C in factorial combination with nights at 14, 18, 22, or 26C. Seedlings of the higher-elevation provenance generally exhibited higher net leaf photosynthetic rates (PN)s than those from the lower elevation at all temperature combinations. Thus, it appears seedlings of the high-elevation provenance possess greater relative thermotolerance, expressed as net photosynthesis, than the low-elevation provenance. Eighty-seven days after initiation (DAI) of the experiment, PN showed a quadratic response to increasing day temperature, with the maximum occurring at 22C, whereas PN decreased linearly with increasing night temperature. At 122 DAI, PN increased linearly with increasing day temperature with nights at 22 and 26C. Highest PNs were at 30/22C and 26/22C. Carbohydrate export increased with increasing day temperature, whereas the response to night temperature was minimal. High levels of nonstructural carbohydrates occurred at thermoperiods (22/22C and 26/22C) that optimize seedling growth. However, definitive trends relating seedling growth to PNs, leaf carbohydrate levels, or to the amount of carbohydrate exported from the leaves were difficult to generalize due to numerous day × night interactions.

NIGHT TEMPERATURE RESPONSE CURVES FOR IN VITRO POLLEN GERMINATION, POLLEN CHARACTISTICS AND FRUITSET IN TOMATO

Previous greenhouse studies in Raleigh have shown that nighttime cooling increases tomato fruit weights from 11% to 53%, depending on planting dates. The physiological mechanism was unclear, except that temperatures during fruitset were most critical We report here on a phytotron experiment comparing pollen characteristics and in vitro pollen germination of plants grown at night temperatures of 18, 22,24 or 26°C in a 12-hour photoperiod with 26°C day temperature in all treatments. There was considerable variability between sampling dates in pollen characteristics and % germination. The most consistent and significant effects were a decrease in total pollen and an increase in % abnormal pollen at high night temperatures. Number of seed present in the fruit also decreased with increasing night temperatures, indicating that the changes in pollen characteristics adversely affected seedset. Night temperatures of 22C appeared optimal for many of the pollen and growth characteristics measured, but fruit developed most rapidly at the higher night temperatures.

Initial Growth of Rosebay Rhododendron Seedlings as Influenced by Day and Night Temperatures

Rosebay rhododendron (Rhododendron maximum L.) seedlings were grown in controlled-environment chambers for 14 weeks under long (9-hour) days at 18, 22, 26, or 30C in factorial combination with 15-hour nights at 14, 18, 22, or 26C. Total dry-matter production was lowest for 18C days and highest for 26C days. A similar response occurred for top, leaf, root, and stem dry weights. Nights at 22C maximized total plant, top, leaf, and stem dry weights. The optimum day/night cycle for dry-matter production was 26/22C. Leaf area was optimum with 18C nights. Leaf weight ratio (leaf dry weight: total plant dry weight) increased with an increase in night temperature to a maximum at 22C. Root weight ratio (root dry weight: total plant dry weight) decreased with an increase in night temperature to a minimum at 22C. Stem weight ratio (stem dry weight: total plant dry weight) and shoot: root ratio (top dry weight: root dry weight) were not influenced significantly by day or night temperature. A day/night cycle of 26/22C seems to be optimal for producing-salable plants.

Initial Growth of Seedlings of Mountain Laurel as Influenced by Day/Night Temperature

Seedlings of mountain laurel (Kalmia latifolia L.) were grown for 16 weeks under long-day conditions with days at 18, 22, 26, or 30C for 9 hours in factorial combination with nights at 14, 18, 22, or 26C for 15 hours. Total plant dry weight, top dry weight, and dry weights of leaves, stems, and roots were influenced by day and night temperatures. The night optimum for all dry weight categories was 22C. Dry matter production was lowest with nights at 14C. Total plant dry weight and dry weights of tops, leaves, and stems were maximized with days at 26C, but for roots the optimum was 22C. Dry weight accumulation was lower with days at 18 or 30C. Responses of leaf area were similar to that of total plant dry weight, with optimum days and nights at 26 and 22C, respectively. Within the optimal day/night temperature range of 22-26/22C for dry weights, there was no evidence that alternating temperatures enhanced growth. Shoot: root ratios (top dry weight: root dry weight) increased with day temperatures up to 30C and were highest with nights at 14 or 26C. Leaf weight ratio (leaf dry weight: total plant dry weight) decreased with increasing night temperature, and increased curvilinearly in response to day temperature with the minimum at 26C. Stem weight ratio (stem dry weight: total plant dry weight) increased with increasing day or night temperature. Root weight ratio (root dry weight: total plant dry weight) was highest with nights at 18 or 22C and decreased with days >22C. Net leaf photosynthetic rate was maximized with days at 26C.

Effects of Day and Night Temperature on Vegetative Growth of Texas Panicum (Panicum texanum)

Texas panicum was grown in controlled-environment chambers in 16 day/night temperature regimes ranging from 19/11 to 34/26 C. After 33 days, maximum plant height, leaf area, and dry weight occurred at 34/26 C. The greatest number of tillers and leaves occurred at 34/16 C. Partitioning of plant biomass into stems increased with increasing night temperature, while partitioning into leaves tended to decrease. Partitioning of biomass into roots decreased with increasing night temperature at day temperatures of 19 or 24 C but not at 34 C. Plant dry matter production (DMP) was highly correlated with both leaf area duration (LAD) and net assimilation rate (NAR) during the first 2 weeks of growth. During the subsequent 3 weeks, DMP was highly correlated with LAD but not with NAR. The low-temperature threshold for growth of Texas panicum was approximately 11 C. Texas panicum attained 25% of its maximum growth at an average daily temperature of 21 C, 50% at 24 C, and 75% at 26 C. Texas panicum is unlikely to become a highly competitive weed outside the southern and southwestern United States.

The effect of the environment on the permeability and composition of Citrus leaf cuticles

The constituents of the soluble cuticular lipids (SCL) of the leaf blades of Citrus aurantium L. were identified by gas chromatography-mass spectrometry and quantified. Major components were 1-alkanols (C24 to C40), n-alkyl esters (C36 to C56), n-alkanoic acids (C28 to C34), n-alkanes (C22 to C40) and triterpenones, while n-alkanals (C29 to C38), sterols, and alkyl benzenes (molecular weights 260, 274 and 288) made minor contributions. Leaf age and side significantly affected the quantitative composition of SCL. Increased day temperature during the development of leaves led to decreased amounts per unit area of n-alkanes, 1-alkanols, n-alkanoic acids and n-alkyl esters while increased night temperatures resulted in increased amounts of n-alkanes n-alkanoic acids and 1-alkanols. Relative humidity had no effect on the amounts or composition of SCL. The permeability of cuticular membranes to water (described in part I of this paper) and the composition of SCL were not related. A model for the molecular structure of the transport-limiting barrier of plant cuticles and for the transport of water across it is proposed.

Control strategies to enhance the performance of greenhouse thermal screens

A simulated comparison was made of five control strategies which could be used to operate greenhouse thermal screens. The energy required to produce an early tomato crop was calculated using a model of the heat loss from a greenhouse and hourly meteorological data. Reductions in yield, caused by reductions in light reaching the crop, were quantified using data from recent horticultural experiments. Using the early tomato regime temperatures, the most effective method of controlling both transparent and high performance aluminized thermal screens was to close the screen whenever the value of the energy saved exceeded the value of the crop lost because of the reduction in light. Almost as good was operating the screen at a specified value of solar irradiance, but delaying, and/or advancing, the opening and closing of the screen by a fixed time interval, was least satisfactory. The fourth method of control involved reducing the day heating setpoint temperature and increasing the night temperature, when the thermal screen was used, to achieve the same 24 h average temperature as occurred in an unscreened greenhouse. This gave greater monetary savings with no crop losses. The final control strategy was a combination of optimized control with reduced day and increased night temperatures. This was the most profitable giving net reductions in heating costs of 26 to 41% depending on the screen and the reduction in day temperature compared to 21 to 33% when the screens were used from sunset to sunrise.

Bromus unioloides H.B.K. main shoot development under different photoperiods and night temperatures

Bromus unioloides H.B.K. main shoot development was studied in plants derived from two natural populations. Plants (from non-vernalized seeds) were grown at three temperatures (17°, 21° and 27°C, respectively) and at two photoperiods (SD: 8 hr of sunlight, and LD: 8 hr of sunlight + 8 hr of low intensity light). Under SD a greater number of leaf primordia occurred in the apices and the number increased as the temperature decreased. The apex initially showed an increase in length and in primordia number. This was followed by a slight decline at 70, 84 and 100 days at 27°, 21° and 17°C, respectively. Apex length was correlated with primordia number ( r 2 = 0.76). The rate of leaf primordia production, unlike that in wheat, was higher under SD than under LD and decreased with increasing night temperatures, and with time. More leaves and spikelets were produced in SD. In LD, the final leaf number and the number of spikelets were lower at 27°C than at 17°C. Floral initiation (single to double ridge) was independent of both length and number of primordia on the apex. In LD this change was observed during the same period at all three temperatures (56–70 days after sowing). In SD it occurred on day 140 at 17° and at 21°C, but the apex was still vegetative at 27°C on day 330. These results might explain the species' greater vegetative production during autumn-winter and its stem extension at the beginning of spring.

Response Surface Analysis of Flowering in Chrysanthemum ‘Bright Golden Anne’

Abstract Chrysanthemum morifolium Ramat. ‘Bright Golden Anne’ plants were grown under 15 combinations of photosynthetic photon flux (PPF), day temperature, and night temperature in a central composite design. Time to flower was a function of both irradiance and the interaction between day and night temperature. The surface response to temperature was bowl shaped with delayed development as temperatures were either increased or decreased from the optimum combinations. High temperature delay was compensated for in part by increased PPF. Shoot length increased linearly as day temperature increased; final shoot length first decreased, then increased with increasing night temperature. The response surface appeared as a rising valley with the longest shoot lengths at high day temperatures. Total flower area per plant increased as PPF increased or as night temperature decreased. For any PPF and night temperature, maximum flower area occurred near 20°C. At a constant PPF, the response surface appeared as a rising ridge with maximum flower area at low night temperature.

Influence of energy-saving night temperature regimes on Botrytis cinerea in an early-season glasshouse tomato crop

Night minimum temperatures of 9°C and a regime with periods of one month at 16°C,and 5°C, followed by 13°C, were compared with a night regime of 13°C for their effects on Botrytis cinerea Pers. in an early-season glasshouse tomato crop. Day temperatures were the same in all treatments. Nine independent compartments were used in a randomized block design in which sub-plots were treated with or without a programme of fungicidal sprays of iprodione started at one of three stages in relation to the first infection by B. cinerea. The low-temperature regime of 9°C significantly increased numbers of lesions caused by B. cinerea on stems and leaves during April and May, but not in subsequent months. Increases during May and June of fallen fruits from 9°C plants were not statistically significant. Stem and leaf infections were not increased by the 16/5/13°C energy-saving regime, although losses due to fallen fruit were greater during May. Treatment with iprodione sprays caused significant decreases in disease in all night temperature regimes and was similar in effect to an increase in night temperature from 9°C to 13°C. Responses to the timing of the first application of iprodione were never significant and differed during the first month of disease assessment only. Yields were significantly lower in the first month of cropping at 9°C but there were no differences in yield between the 13°C and the 16/5/13°C regimes.

EFFECTS OF TEMPERATURE, LEVELS OF NITRATE SUPPLY AND DURATION OF LIGHT AND GROWTH ON NITRATE REDUCTASE ACTIVITY IN AGEOSTIS TENUIS AND AGROSTIS STOLONIFERA

SUMMARYNitrate reductase activity (NRA) was assessed at several moments within the day during the early stages of establishment of tiller generated plants and seedling swards of Agrostis tenuis and A. stolonifera grown at different temperatures and levels of nitrate supply. Agrostis tennis consistently exhibited higher NRA values than A. stolonifera at initial developmental stages or low nitrate availability. The reverse situation was found to occur at high nitrate availability or in longer established plants and seedling swards. This emphasizes the difficulties in establishing consistent differences between species in NRA. Both species showed increased NRA with increased nitrate availability, increased night temperature or decreased day temperature. Agrostis stolonifera increased its NRA to a greater extent than A. tenuis as nitrate availability increased. The importance of daily and developmental variation in NRA in establishing differences between these species is discussed.

Improved Flowering and Pollen Fertility in Sugarcane under Increased Night Temperatures1

A shortage of male fertile sugarcane clones often restricts cross‐pollination at the Meringa Sugar Exp. Stn. Extensive pollen testing revealed substantial variability on a micro‐environmental scale, indicating the environment may be sub‐optimal for pollen development.Four clones from each of three flowering groups (early, mid, and late season) were chosen on the basis consistent flowering but variable pollen stainability. Two adjacent replicated field trials were planted. One trial was enclosed at night with a mobile plasticsheathed shed and maintained at 22 to 23 C from 22 March, 2 weeks after photoinduction commenced, until 15 June 1979, 6 days before routine cross‐pollination finished. After 22 March, the average external minimum temperature was usually well below 21 C, regarded as critical for good pollen fertility development in sugarcane.The heated environment produced more profuse flowering (77 vs. 61%, for the whole season; 64 vs. 35%, during cross‐pollination), increased panicle availability for crossing (84 vs. 57%), and accelerated flowering by an average of 12 days. This latter effect provides an additional technique for making crosses among clones which do not normally flower at the same time.Pollen production in both environments was similar but stainability (starch‐iodine test) was significantly higher in the heated environment (19 vs. 9%, stained grains). The later the flowering group, the greater was the improvement obtained.Crosses using male flowers from the heated environment produced significantly more seedlings (614 vs. 325/5 g “seed”, in 16 paired crosses; 572 vs. 225, over 78 crosses).The heated environment significantly increased flowering, pollen stainability, and germination count and is expected to have an important practical application.

Crassulacean acid metabolism (CAM) in Kalancho� daigremontiana: Temperature response of phosphoenolpyruvate (PEP)-carboxylase in relation to allosteric effectors

Net CO2 dark fixation of Kalanchoë daigremontiana varies with night temperature. We found an optimum of fixation at about 15° C; with increasing night temperature fixation decreased. We studied the temperature dependence of the activity of phosphoenolpyruvate (PEP)-carboxylase, the key enzyme for CO2 dark fixation. We varied the pH, the substrate concentration (PEP), and the L-malate and glucose-6-phosphate (G-6-P) concentration in the assay. Generally, lowering the pH and reducing the amount of substrate resulted in an increase in activation by G-6-P and in an increase in malate inhibition of the enzyme. Furthermore, malate inhibition and G-6-P activation increased with increasing temperature. Activity measurements between 10° C and 45°C at a given concentration of the effectors revealed that the temperature optimum and maximum activities at that optimum varied with the effector applied. Under the influence of 5 mol m(-3) L-malate the temperature optimum and maximum activity dropped drastically, especially when the substrate level was low (at 0.5 mol m(-3) PEP from 32° C to 20° C). G-6-P raised the temperature optimum and maximum activity when the substrate level was low. If both malate and G-6-P were present, intermediate values were measured. We suggest that changes in metabolite levels in K. daigremontiana leaves can alter the temperature features of PEP-carboxylase so that the observed in vivo CO2 dark fixation can be explained on the basis of PEP-carboxylase activity.

Influence of Various Growth Chamber Environments on Growth, Flowering, and Senescence of Tulipa gesneriana L. cv. Paul Richter1

Abstract ‘Paul Richter’ tulips were forced in controlled environment chambers at 26/22, 22/18, and 18/14°C day/night temperatures using high and reduced light intensity and short and long daylengths. Photoperiod had no influence on growth or flowering. Reduced light intensity with the coolest temperature treatment significantly increased the forcing period. Increased forcing temperatures had the greatest impact on plant growth, resulting in reduced Plant flower length, and forcing period. In a second experiment, ‘Paul Richter’ was forced in controlled environment chambers under 8 combinations of day/night temperatures from 18 to 26° day and from 14 to 22° night. The warmer day or night temperatures decreased the forcing period. Plant height was increased with increasing day temperatures, but decreased with increasing night temperature. Flower length decreased with increasing day or night temperatures. First internode length was increased with increasing day temperature but decreased with increasing night temperature, with the exception of a slight increase at a day temperature of 18°. Last internode length was increased only slightly with increasing night temperature. Flower longevity and total length were decreased slightly by increased forcing temperatures.

The role of night temperature in the bulbing of onion (Allium cepa L.)

Onion (Allium cepa L.) cultivars Creamgold and Gladalan Brown were grown at three day lengths (13, 14 and 15 h) and three day temperatures (22, 26 and 30�C) in the Canberra phytotron. In each case bulbing was slower whcn the night temperature was 15' below day temperature than at 5� below day temperature. The cultivar Gladalan Brown, growing at 13 h day length and 26�C day temperature, bulbed faster when the first half of the 11 h night was at 21� and the second half at 11� than in a 11� then 21� night. The number of days from sowing to the start of bulbing decreased with increasing night temperature. The rate of bulbing after initiation increased with increasing night temperature.

Carbon Dioxide Assimilation by Pineapple Plants, Ananas comosus (L.) Merr. II. Effects of Variation of the Day/Night Temperature Regime

The effects of variation of day/night temperature regime on the diurnal patterns of CO2 assimilation of pineapple plants were examined using single leaf and field enclosure methods. At day temperatures of 30°C, increasing night temperatures from 20 to 35°C reduced the total assimilation of CO2 per daily light/dark cycle from 6.5 to 1.3 g CO2 m-2 (leaf area) day-1, and also reduced the proportion of total CO2 assimilation that occurred at night from c. 90% to c. 40%. Decreasing day temperatures (30 to 10°C) had little effect on total daily CO2 assimilation in warm (25°C) nights, but reduced it in cooler (15°C) nights. At day temperatures of <152C, CO2 assimilation took place predominantly (60-100%) in the photoperiod. In cool (10°C) days, the normal inverted stomatal rhythm of CAM plants was reversed; leaf conductance was high (c. 1.0 mm s-1) throughout the photoperiod and a large CO2 efflux was observed, lasting c. 2 h, at the beginning of the dark period. Leaf conductance of pineapples, by day and by night, is strongly influenced by ambient temperatures, with cool conditions favouring stomatal opening.

Effects of night temperature on the growth of Nicotiana tabacum

Four varieties of flue-cured tobacco, Nicotiana tabacum L., showed similar responses to night temperatures of 10�, 16�, 22�, and 28�C, with a day temperature of 27�C. Leaf growth rates and leaf production rates were approximately the same at night temperatures of 28� and 22�C, and were successively lower at 16� and 10�C. Dry weight accumulation was greatest at 22�. The node number of flower initiation increased with increasing night temperature over the whole range. There was no evidence of either a shift in the night temperature optimum or a physiological adaptation to low temperature during development.

The effect of high temperature regimes or short periods of water stress on development of small fruiting saltana vines

Poor fruit set of sultanas in the Murray Valley is sometimes attributed to excessively high temperatures around flowering time. Experiments with small fruiting sultana vines in pots suggest that water stress is the more important factor. Fruit set was significantly less when a 3-day period of water stress was imposed at flowering or 1, 2, or 4 weeks after flowering, but not when it was imposed 6 weeks after flowering. Three days with maximum temperatures above 45°C at or 1 week after flowering did not reduce fruit set when ample water was supplied. When controlled environments combining day temperatures between 21 and 30°C with night temperatures between 19 and 25° were used, no significant differences in fruit set were found, although shoot growth increased with increasing night temperature. Shoot elongation slowed down during periods of applied water stress but recovered, when the stress was ended, to a rate greater than that of plants which had not been stressed.

The effects of temperature and day length on species of Eucalyptus

Seedlings of Eucalyptus bicostata, E. blakelyi, E. niphophila, E. pauciflora, E. polyanthemos, E. rubida, and E . Stelldata were grown under various defined temperature and day-length regimes and response was assessed in terms of height, dry weights of stems, roots, leaves, and branches, number of leaves and branches, and leaf shape. Seedlings of E. bicostata, E. blakelyi, E. niphophila, E. pauciflora, and E. Rubida were capable of continuous growth under short days (8 hr) provided temperature conditions were appropriate. These species can be allocated, therefore, to Class C of Nitsch (1957). Growth was greater under long days of 18 hr than under short days of 8 hr. Irrespective of the temperature regime operating, the order of dry weight increase over 60 days was: E. bicostata > E. blahelyi > E. polyanthemos > E. niphophila. Growth of E. bicostata, E. blalcelyi, and E. polyanthemos increased as mean temperature levels increased thus: 14/8°C, 19/11°C, 20/17°C, 25/20°C. Further increase to 27/24°C had an adverse effeot upon growth of E. polyanthemos, but not on that of E. bicostata and E. blakelyi. Increasing night temperature from 6°C to 24°C when the day temperature was either 11, 20, 24, or 28°C generally increased height, dry weights of stems, roots, and leaves, and total leaf area of E. blakelyi. Similar effects were produced when day temperatures were increased from 11°C to 2S°C, night temperatures being either 6, 16, 19, or 24°C. Consequently, under short days of winter, the 28/24°C regime was most nearly optimal for growth. Adverse effects on growth appeared to be produced when night temperature exceeded a low day temperature (as under the 11/24°C regime). Average day and night temperature interacted in a statistically significant way upon growth. In E. paucifiora, increasing night temperature from 8°C to 24°C when the average day temperature was either 14, 20, 25, or 27°C, and increasing day temperature from 14°C to 27°C when night temperature was 8, 17, 20, or 24°C increased growth. Thus, the regime 27/24°C approached the optimum for growth, as in E. blakelyi. In E. blakelyi and E. paucifiora, branching was most restricted in plants which were tallest. There were indications that the magnitude of diurnal temperature fluctuations might be important in determining the degree of lateral branching (apical dominance). Leaf size, shape, and number were related to day length and temperature conditions. Leaf shape (as measured by length/breadth ratios) was a function of day and night temperatures, not being significantly related to either alone. Day length appeared to exert a more pronounced effeot upon leaf shape (long days tending to shift shape in the direction juvenile → adult) than temperature. The ratios top/root and leaflstem, especially the latter, were significantly lower in E. blakelyi than in E. pauciflora.