Low Night Temperature Research Articles

Effect of night temperature on daytime stomatal conductance in early and late successional plants.

Sixteen annuals, biennials, and herbaceous and woody perennials characteristic of early and late successional old field ecosystems and upland and floodplain habitats were analyzed for their response of stomatal conductance to changes in night temperature. Early successional species that germinate in early spring when temperatures are low, but above freezing are insensitive to cool nights, i.e., their conductance in the following days is unaffected by low night temperature. Later spring and summer-emerging species' stomatal conductance is inhibited by low temperatures. Tree species show the same effects and in some an enhancement of stomatal conductance by low night temperatures was observed. However, adaptive differences in response to night temperatures appear related to both phenology of germination and growth and habitat types.

SUPPLEMENTAL HIGH PRESSURE SODIUM LIGHTING AND NIGHT TEMPERATURE EFFECTS ON SEED GERANIUMS

F1 seed-propagated geraniums (Pelargonium × hortorum Bailey) flowered earlier when plants received in excess of 400 E∙m−2 cumulative photosynthetically active radiation (PAR). Two out of three cultivars grown at 17 °C night temperature which received 443 E∙m−2 natural lighting or 341 E∙m−2 natural plus 102 E∙m−2 high pressure sodium lighting (HPS) over a 4-wk period following transplanting flowered earlier. Flowering was accelerated by 2 wks when a total of 920 E∙m−2 cumulative PAR (726 E∙m−2 natural plus 194 E∙m−2 HPS) was received by plants over an 8-wk period. Reducing night temperature from 17 to 13 °C delayed flowering by 2 wk. Supplementary HPS irradiation for 6–8 wk overcame the delay in flowering induced by low night temperature and produced compact plants with more shoots.

GROWTH OF CORN SEEDLINGS: EFFECTS OF NIGHT TEMPERATURE UNDER OPTIMUM SOIL MOISTURE OR UNDER DROUGHT CONDITIONS

Emergence and early seedling growth of two corn hybrids, Stewart 2300 and B73 × Mo17, were studied in growth cabinets in which night temperatures ranged from 5 to 20 °C. Emergence was more rapid at higher night temperatures and the two hybrids had relatively constant growing degree day (base temperature of 3 °C) requirements to reach 80% emergence. Both leaf area and dry matter increased most rapidly under 15 °C night temperatures and relative growth rate and net assimilation rate decreased with lower night temperatures when moisture was adequate. Under drought conditions, however, night temperature had little effect on growth rate. These findings indicate that cool night temperatures lead to reductions in photosynthesis. The finding that drought reduces the effects of cool night temperature is consistent with the theory that photosynthesis is reduced after cool nights because stomatal opening is inhibited by a temperature-induced water deficit.

Phloem Transport and the Regulation of Growth of Sorghum bicolor (Moench) at Low Temperature

Leaf expansion in Sorghum bicolor (Moench) was severely retarded by low night temperatures (5 C). However, this was not reflected in the early measurements of relative growth rate, indicating that the response was not associated with a deterioration of the photosynthetic system. For plants grown at 30/25 C (day/night) and subsequently held at an ambient temperature of 30 C, phloem transport, as measured either by the movement of (14)C-photosynthate through a zone of controlled temperature or by accumulation of dry matter distal to this zone, was inhibited by temperatures below 10 C. The speed of movement of (32)P through the temperature controlled zone was more sensitive to temperature with reductions apparent below 20 C. Although there was some recovery in the movement of (32)P following 3 days equilibration at low temperature (1 to 10 C), the new values (approximately 100 centimeters per hour) were still only about one-third of those obtained in the high temperature controls. For plants held at an ambient temperature of 21 C, which is well below the optimum for growth, translocation was only inhibited by temperatures below 5 C. Although low temperature may reduce the carrying capacity of the phloem of S. bicolor, this is unlikely to be an important factor in regulating the growth of the plants at low temperatures.

EFFECT OF TEMPERATURE AND PHOTOPERIOD ON GROWTH AND DORMANCY OF BETULA PAPYRIFERA

The effects of day/night temperatures and photoperiod on the growth and dormancy of paper birch (Betula papyrifera) were studied in seedlings from different geographic origins. The response of Alaskan plants to temperature and photoperiod was distinctly different from other seed sources. Alaskan plants required very long days to prevent cessation of growth while plants from southern seed sources grew on photoperiods as short as 14 hr. Low night temperature (14 C) antagonized the promotive action of long photoperiods in Alaskan plants but had little effect in other seed sources. High day temperatures offset the inhibitory effect of the cool night to a lesser degree in Alaskan plants than in plants from other locations. Dormancy induced by short photoperiods was antagonized (relieved ?) to a lesser degree by high night temperatures in Alaskan birch than in other seed sources. Betula papyrifera var. humilis from Alaska may be an incipient species since its morphological traits are accompanied by adaptive physiological responses to its environment. These responses are as distinct as its morphological characteristics.

Adaptations to low temperature in high altitude insects from Mount Kenya

Abstract. 1. The strategies for low temperature survival in insects on Mount Kenya were investigated. The insects were collected from their natural habitats and their supercooling points and low temperature tolerances determined.2. Most insects showed no special adaptations to low temperature survival and seem to depend on spending the cold nights in protected habitats, such as beneath stones and fallen trunks of plants, as well as within the wet frills of dead leaves of alpine plants, where they are protected by the heat released from freezing water.3. Some insects, e.g. Collembola, aphids and a curculionid beetle, which live in relatively unprotected habitats, had low supercooling points, allowing them to remain unfrozen when exposed to low night temperatures. A nucleator free diet is apparently essential for the survival of such species.4. Two species of curculionid beetles were found to withstand freezing down to ‐7d̀C. These beetles had nucleating agents in their haemolymph and higher supercooling points than most of the other species studied.5. A moderate freezing tolerance was found in larvae of a midge that lives in the watery liquid between the leaves of Senecio brassica.

EXPERIMENTAL ECOLOGICAL GENETICS IN PLANTAGO IV. EFFECTS OF TEMPERATURE ON GROWTH RATES AND REPRODUCTION IN THREE POPULATIONS OF PLANTAGO LANCEOLATA L. (PLANTAGINACEAE)

The effects of temperature on growth rates and flowering responses of Plantago lanceolata L. populations sampled from open, shaded, and sunflecked habitats were studied in controlled environments. A large number of characteristics were phenotypically plastic in response to a broad range of temperatures. Low night temperatures substantially reduced reproductive effort, whereas high temperatures produced a reduction in total biomass. Temperature had little effect on leaf or inflorescence production rates, other than at very low temperatures. The phenotypic plasticity observed in the growth chamber correlated well with the observed seasonal phenology. Genetic differences were found in inflorescence height and total plant productivity. The rapid growth rate, the high reproductive effort, and generally broad temperature optimum to moderate temperatures are consistent with the occurrence of P. lanceolata in a wide variety of disturbed habitats in temperate latitudes.

Experimental Ecological Genetics in Plantago IV. Effects of Temperature on Growth Rates and Reproduction in Three Populations of Plantago lanceolata L. (Plantaginaceae)

The effects of temperature on growth rates and flowering responses of Plantago lanceolata L. populations sampled from open, shaded, and sunflecked habitats were studied in controlled environments. A large number of characteristics were phenotypically plastic in response to a broad range of temperatures. Low night temperatures substantially reduced reproductive effort, whereas high temperatures produced a reduction in total biomass. Temperature had little effect on leaf or inflorescence production rates, other than at very low temperatures. The phenotypic plasticity observed in the growth chamber correlated well with the observed seasonal phenology. Genetic differences were found in inflorescence height and total plant productivity. The rapid growth rate, the high reproductive effort, and generally broad temperature optimum to moderate temperatures are consistent with the occurrence of P. lanceolata in a wide variety of disturbed habitats in temperate latitudes.

Studies on Matter Production of Rape Plant : IV. Diurnal changes in apparent photosynthesis and dark resiraton of rape plants under field conditions

Diurnal variations in CO2 exchange of rape plants were observed over 2-4 successive day at about two-week's intervals from their early growth to full maturity. The measurement of CO2 exchange was conducted using an assimilation chamber in which conditions were regulated as similar as possible to those of the outside. Principal environmental factors, i.e., total solar radiation, diffused solar radiation, air temperature, soil temperature, air humidity and CO2 concentration of air were recorded simultaneously writh CO2 exchange. From the data obtained, dependence of the CO2 exchange rate on the environmental factors was examined. In addition, the after-effects of low night temperature on daytime photosynthesis, the existence of which had been suggested by the result of field observations, were examined under controlled conditions. The results obtained are summarized as follows: 1. The photosynthetic rate depended primarily on total solar radiation throughout daytime on all the days when observations were conducted. 2. Based on the mode of correspondence between the photosynthetic rate and total solar radiation at each time of a day, patterns for diurnal variations in photosynthesis were grouped into the following two types. Type A: In this type, photosynthetic rates in the morning were nearly equal to those in the afternoon provided they were compared at equivalent solar radiation levels. Type B: In this type, photosynthetic rates in the morning were lower than those in the afternoon even compared at equivalent solar radiation levels. 3. The pattern of Type A was observed on cloudy days, or on fine days whose preccding night was not so cold or warm. The pattern of Type B was observed on fine days preceded by a very cold night. 4. Type B predominated in winter while Type A prevailed in other seasons. 5. The dark respiration rate at night varied mainly with air temperature at each stage of growth. 6. It was confirmed in the experiment under controlled conditions that the photosythetic rate in the daytime was affected by the air temperature of the preceding night. Night temperatures below a certain limit brought about depression of photosynthesis during the succeeding daytime. The lower the night temperature, the lager the extent of depression and the longer time required to recover from the depression.

Reduced night temperature effects on poinsettias

The critical time to lower night temperature from 18° to 13°C for poinsettia (Euphorbia pulcherrima Willd.) cv Dark Red Annette Hegg was five weeks following the start of short photoperiods. Prior ...

Response of stomatal resistance and photosynthesis to night temperature in Populus deltoides.

Ramets from stem cuttings of three populations of Populus deltoides Bartr. from Wisconsin, Illinois, and Louisiana representing a latitudinal gradient were grown in pots outdoors at Urbana, Illinois and brought indoors for growth chamber studies. Leaf resistance and photosynthetic response to low night temperatures of 4° and 10° C were determined relative to 20° C controls for plants measured over one growing season. Plants from Louisiana, where nights are warm, reacted to cool nights of 4° and 10° C by opening their stomata slower upon illumination the following day than those from farther north where nights are cooler. The optimum night temperature for rate of opening was lower in the Wisconsin population than in populations from farther south. The Wisconsin population showed more ideal homeostasis of photosynthesis at different temperatures than the southern population which exhibited greater plasticity. No seasonal differences in these relationships were apparent other than at the time of leaf senescence.As plants approached senescence, which occurred earliest in the Wisconsin population, leaf resistance increased and photosynthesis declined, but stomata still retained their functional ability to respond to changes in night temperature. The change in leaf resistance, noted in the Wisconsin population, was related more to closure of lower-leaf surface stomata than upper. Only the Louisiana population had significantly more stomata on the lower than upper leaf surface.

Male Sterility in Sorghum bicolor (L.) Moench Induced by Low Night Temperature. II. Genotypic Differences in Sensitivity

Three genotypes of sorghum grown in controlled environments were compared for low temperature sensitivity during the leptotene stage of microsporogenesis. Treatment regimes imposed during this period were 21°C day and 14,11, 8 or 5°C night. A known sensitive hybrid (CK60 × Tx415) showed progressive reduction in pollen proline level, percentage starched pollen, and seed set with decreasing night temperature, indicating that sterility induction was a quantitative response to night temperature. The line 606, deveIoped at high altitudes in Mexico, was fertile under all treatment regimes. The hybrid CK60 × 606 was intermediate in response for pollen fertility, but pollen fertility was still sufficient to enable near complete seed set in all treatments. Factors considered important in breeding grain sorghums with low-temperature-tolerant microsporogenesis are discussed.

Tropical-Alpine Life-Forms of Vascular Plants

The alpine flora of the high East African mountains is renowned for its Giant Senecios, Giant Lobelias, and other weird growth forms. Detailed studies of this afroalpine flora have led to a description of five life-forms of vascular plants, the morphological peculiarities of which are interpreted as ecological adaptations to the tropical-alpine climate with recurrent night frosts throughout the year. The same life-forms occur under similar climatic conditions in other tropical high mountains, notably in the South American Andes. A comparison was made between tropical-alpine life-forms and temperature conditions of Africa and South America. The results support the hypothesis that those life-forms result from parallel adaptive evolution responding to extreme environmental conditions. The crucial factor seems to be the low night temperatures, and most morphological specializations can be interpreted as adaptations favouring temperature insulation and the maintenance of the water balance.

Temperature Responses and Potential Distribution of Itchgrass (Rottboellia exaltata) in the United States

To estimate the potential growth and distribution of itchgrass (Rottboellia exaltata L. f.) in the United States, we grew the plant in 36 combinations of day and night temperatures in controlled-environment greenhouses. Day temperatures ranged from 17 to 32 C and night temperatures from 11 to 26 C. Total dry weights, leaf areas, heights, and numbers of tillers were determined at 3, 31, and 58 days after emergence. Mathematical growth analysis techniques were used to calculate net assimilation rates (NAR) and leaf area durations (LAD). Maximum dry matter production (the product of NAR and LAD) and maximum leaf area production occurred at 32/26 C. Dry matter production and leaf area production were greatly reduced by day temperatures below 29 C and night temperatures below 23 C. The retardation of dry matter production by low night temperature was due mainly to reductions in LAD rather than to reductions in NAR. Low day temperatures reduced dry matter production through combined effects on LAD and NAR. At the warmer day temperatures, tiller production increased with decreasing night temperature. Flowering occurred at all day temperatures and at all night temperatures of 14 C or greater. Based on its growth responses to temperature, itchgrass would reach 75 to 100% of its maximum potential growth in the Gulf Coast states, the lower Midwest, the South Atlantic states, and the Southwest. Therefore, it represents a serious potential weed problem in these regions.

Influence du bocage sur le climat d'une petite region: Resultats des mesures effectuees en bretagne

Within a more general frame of a multi-disciplinary study initiated in Brittany (north-west France), a special programme was carried out by the INRA Station de Bioclimatologie d'Avignon-Montfavet to determine the influences of hedge networks (“bocage”) on the climate of a small region. The study, based on theoretical studies described elsewhere, consisted of comparative micrometeorological and meteorological measurements taken in nearby sites, one within the old original ‘bocage’ landscape and the other where land management operations had led to more or less total destruction of the hedge system. The study first considers the aerodynamic effects due to the modification of air flow by the hedge system, which may be related to the general aerodynamic roughness corresponding to the height and density of obstacles. Then follow the results regarding the radiation balance, which showed no noticeable modification of net radiation, the slight increase in infra-red loss being compensated by a similar slight increase in absorbed solar radiation due to a smaller albedo. These combined effects generally induced higher daytime and lower night temperatures, resulting in an increase in the diurnal range (0.5°–1.5°C). An increase in air saturation deficit also occurred, especially on the sea border (0.5-3 mbar). Although evaporation measured by a Piche evaporimeter showed a marked reduction (about 30%), no such effect appeared in potential evapotranspiration ( PET), which can be explained by the low weight of the advective term (to which the Piche instrument is sensitive) in the Penman formulae in comparison with the radiation term in the specific context of the climate of Brittany.

Effect of night temperature and growing-practices on the winter yield of roses

The effect of night temperatures on the yield and quality of the rose, cultivars ‘Baccara’, ‘Sonia’ and ‘Belinda’, was studied during the winters of 1974/75 and 1975/76. Lower night temperature decreased the number of saleable flowers, reduced flower stem length, and increased ‘Baccara’ flower malformation. Sacrificing autumn yield (October–November) increased the number of mid-winter flowers and their stem length while significantly decreasing ‘Baccara’ flower malformation. The favorable response to sacrificing early yield is attributed to an enhanced rate of lateral bud breaking, as well as to a prolonged accumulation of summer metabolites and a more satisfactory balance of growth substances which reduce the incidence of flower malformation.

The influence of temperature and light on parthenocarpy in pickling cucumbers (Cucumis sativus L.).

Parthenocarpy was influenced unfavourably by high temperatures. The effect of high day temperatures could partly be compensated by low night temperatures. A temperature regime of 23/17 deg C seemed to be optimal. The influence of daylength and light intensity are discussed. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Triphasic Feeding Behavior and the Esophageal Diverticulum in Redpolls

Most adaptive characteristics of redpolls (Acanthis spp.) are keyed to surviving an arctic or subarctic winter, where energy balance is the severest problem. Many features combine to produce the total adaptation that makes these tiny birds some of the most cold-hardy of homeotherms (Brooks 1965, Ph.D. thesis, Univ. Illinois, Urbana), but the presence and specialized use of the esophageal diverticulum may be among the most important. It is a partially bilobed, ventrolateral outpocketing located about midway on the neck, found in redpolls and certain other northern finches (e.g. crossbills, Loxia spp.) but absent in most other passerines (Fisher & Dater 1961, Auk 78: 528). The ventral, unilobed in galliformes and others is only somewhat analogous in structure and function. The adaptive value of the diverticulum manifests itself in three aspects: (1) energy gained, (2) energy saved, and (3) reduced predation. Extra food is stored there toward nightfall, carrying the bird through low night temperatures when it is unable to feed. I have estimated that the amount of birch seeds that could be stored in the diverticulum by Common Redpolls (A. flammea) and used at night would allow survival to -62?C, a substantial increase in cold tolerance over the -30?C that could be tolerated without that extra energy (Brooks 1968, Wilson Bull. 80: 253). A hitherto unreported use of the diverticulum is as an energy saving device. During the winter finch invasion of 1971-72 in Ripon, Wisconsin, I observed that individual redpolls hurriedly selected millet from the seed mixture at a feeder, then flew away. This produced a constant, rapid turnover of the feeding flock. There were never more than about 100 birds feeding, but mark-recapture banding data indicated that 1,000-1,500 different redpolls utilized the feeder daily. Little agonistic interaction was noted while feeding. Individual Evening Grosbeaks (Hesperiphona vespertina), however, remained for fairly long periods shelling sunflower seeds, and many intraspecific agonistic encounters were seen. Closer observation showed other differences between the species. Especially on colder days, redpolls ingested seeds rapidly without shelling them. As some individuals ceased feeding they left the flock and congregated in a dense white cedar about 2 m from my observation window. Although they appeared to be resting, plumage fluffed out in the heat-saving position typical at low temperature, they were actually regurgitating, shelling, and reingesting millet seeds. Due to the numbers processed by each bird I assume these seeds had been held in the diverticulum. The primary natural food of redpolls is birch seed, about the size of poppy seed. Typical wild feeding behavior at first appears distinctly biphasic. The birds, using wings, legs, head, and tail vigorously, spend a short time working acrobatically among the terminal branchlets in phase I, knocking seeds out of the catkins. This muscular activity consumes more energy, and because of the consequent insulation disruption and greater exposure to wind, they lose relatively more calories than in phase II. They spend a longer time in phase II gathering these seeds from the ground (snow, usually) where there is less wind, where they can remain more easily in a ball position, but where they are probably more exposed to the view of predators (on snow). Energy rather than predatory considerations thus may shorten phase I. Biphasic feeding is already more complex than the feeding of most other birds, but redpoll feeding is actually a triphasic process. In phase III cover is sought and seeds stored in the diverticulum are shelled. This advanced type of feeding behavior, to my knowledge, is unique among birds but is fairly similar to that of the red squirrel (Tamiascirus hudsonicus), another boreal treetop harvester. The two obvious benefits of phase III are that additional energy is saved and potential predators are avoided. The energy saving involves four factors. One is that seeds are undoubtedly softened by moisture in the diverticulum, making hulls easier to remove and allowing easier mastication of the hydrated edible portions in the gizzard. Slightly less energy is expended for this necessary work (though some calories are lost in heating expelled hulls and water), and more is thus available for body heat production or other activities. This hydration phenomenon is quite reminiscent of cud-chewing in ruminants, whose stomach compartments allow proper separation of processed from unprocessed food. It is probable that the need for efficient separation is the reason that the esophageal pouches in redpolls are laterally oriented. The question has been raised (Fisher & Dater op. cit.) as to why the diverticulum is not ventral as the crop is in

Photosynthesis and nonstructural carbohydrate concentration in leaf blades of Panicum virgatum as affected by night temperature

Panicum virgatum is considered a relatively cold-tolerant C4 species to low night temperature from analysis of top growth, photosynthesis, dark respiration, and day–night fluctuation of nonstructural carbohydrate concentration in leaf blades grown under temperature regimes of 30–30, 30–20, and 30–10 °C. There was little influence of night temperature of 10 to 30 °C on top growth, although 20 °C night temperature was optimum. Plants grown under low night temperature (10 °C) showed a slightly reduced rate of photosynthesis early in the photoperiod, while plants at 30 °C night temperature had the highest rates of dark respiration. The time required for the plants to reach maximal photosynthetic rate from the beginning of the photoperiod was prolonged with decreased night temperature, being 1.0, 1.5, and 2.5 h for plants grown at 30–30, 30–20, and 30–10 °C regimes, respectively. Photosynthetic rates progressively declined during the rest of the photoperiod. The change in photosynthetic rate during the photoperiod and influence of night temperature on photosynthesis was highly correlated with the change in stomatal resistance to CO2 transfer (r = −0.9). Starch and total sugars in leaves accumulated slightly with time after initiation of the photoperiod and then were reduced to low levels during the night at all temperatures. Night temperature had no effect on the accumulation of these nonstructural carbohydrates during the day or on depletion from the leaves during the night.

On the influence of Low Night Temperature during the Panicle Formation Period upon the Sterilization of Rice Grains (Preliminary report)

On the influence of Low Night Temperature during the Panicle Formation Period upon the Sterilization of Rice Grains (Preliminary report)