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Photoperiodic flowering responses are classified into three major types: long day (LD), short day (SD), and day neutral (DN). The inverse responses to daylength of LD and SD plants have been partly characterized in Arabidopsis and rice; however, the molecular mechanism underlying the DN response is largely unknown. Modern roses are economically important ornamental plants with continuous flowering (CF) features, and are generally regarded as DN plants. Here, RcCO and RcCOL4 were identified as floral activators up-regulated under LD and SD conditions, respectively, in the CF cultivar Rosa chinensis ‘Old-Blush’. Diminishing the expression of RcCO or/and RcCOL4 by virus-induced gene silencing (VIGS) delayed flowering time under both SDs and LDs. Interestingly, in contrast to RcCO-silenced plants, the flowering time of RcCOL4-silenced plants was more delayed under SD than under LD conditions, indicating perturbed plant responses to day neutrality. Further analyses revealed that physical interaction between RcCOL4 and RcCO facilitated binding of RcCO to the CORE motif in the promoter of RcFT and induction of RcFT. Taken together, the complementary expression of RcCO in LDs and of RcCOL4 in SDs guaranteed flowering under favorable growth conditions regardless of the photoperiod. This finding established the molecular foundation of CF in roses and further shed light on the underlying mechanisms of DN responses.

In June 2012, I spent a week on Davidson Glacier, above Haines, Alaska. Seven of us formed two rope teams of climbers, learning how to travel safely across a big river of ice. Every morning for seven days, we roped up and snowshoed across the glacier, then strapped on crampons and climbed up unnamed peaks of the Chilkat Range. Late every afternoon, we would trudge back to camp across the glacier, barely lifting our feet and listening to the shuffle of the snowshoes. The sun stayed out most of the night, but it didn’t stop us from sleeping soundly. One evening we were following our own snowshoe tracks back to camp after a long day of climbing. Suddenly, we all saw a distinct set of large tracks running right across our snowshoe prints from the morning. The wide paw tracks were the size of a human hand, and in the ice, you could see pads and claw marks, three middle ones very sharp. The tracks spread far apart, and they ran in a clear line from a ridge to the south of us, across the expanse of the glacier, toward a mountain that our instructors called The Dragon. Wolverine. It was as if you could see the intensity of the animal, an animal maybe 35 pounds or more, loping across the glacier from one mountain range to another, covering as much as 40 miles in a given day. The wolverine didn’t need snowshoes or crampons or ropes; his equipment was built in. Some of my companions may have been as awe-struck as I was. It was the first time any of us had seen tracks of a wolverine, and certainly the closest I had come to one. The tracks were exciting; they made me look across at The Dragon and wonder if we could ever climb it like the wolverine. We crossed the ice to camp with renewed energy

In seasonally breeding birds, the annual cycle of photoperiod is a principal environmental cue for temporal arrangement of different life-history stages, such as migration and breeding. In the past, most research has focused on the mechanisms of photoperiodic control of breeding with less attention paid to migration. In Gambel’s white-crowned sparrow Zonotrichia leucophrys gambelii (GWCS), photoreceptors for induction of breeding are known to reside in the basal hypothalamus. However, it is unknown whether the sites of photoperiodic reception for vernal migration are the same as those for breeding. Therefore, we hypothesized that they may be controlled separately. In this study, we exposed photosensitive GWCSs to low-penetration green light (wavelength at 510 nm) under a regime of 1 lux during the day and

Two experiments were conducted to determine whether exposure to a photoperiod of arti- ficial long days in autumn increased milk yield in sub- tropical goats milked once (Exp. I) or twice daily (Exp. II). In Exp. I, starting at d 10 of lactation, 1 group of does was kept under naturally decreasing photoperiod (DD1X; n = 8), whereas the other group was submitted to an artificial photoperiod of long days (LD1X; n = 8; 16 h light:8 h darkness). The kids were weaned 28 d after parturition, and dams were manually milked once daily. Milk yield and milk components (fat, protein, and lactose) were assessed up to 140 d of lactation. From d 0 to 28 of lactation (suckling phase), mean daily milk yield did not differ between DD1X and LD1X goats (2.3 ± 0.2 kg vs. 2.4 ± 0.2 kg; P = 0.717). However, between d 29 and 84 (early milking phase), mean daily milk yield was greater in LD1X does than in DD1X does (2.6 ± 0.1 kg vs. 2.1 ± 0.1 kg; P = 0.001). Finally, between d 85 and 140 (late milking phase), mean daily milk yield was greater in LD1X goats than in DD1X goats (P ≤ 0.05) only during the first 2 wk. In Exp. II, one group of goats was exposed to a photoperiod of naturally decreasing days (DD2X; n = 8) and an- other group was submitted to an artificial photoperiod of long days (LD2X; n = 7). In both groups, kids were weaned on d 28 of lactation and the dams were manu- ally milked twice daily. During the nursing phase, mean daily milk yield did not differ between the DD2X and LD2X groups (2.5 ± 0.3 kg vs. 2.6 ± 0.2 kg; P = 0.767). In the early milking phase, mean daily milk yield was greater in LD2X than in DD2X goats (3.3 ± 0.2 kg vs. 2.8 ± 0.2 kg; P = 0.022), whereas during the late milking phase, milk yield did not differ between the 2 groups (P = 0.946). In both experiments, milk compo- sition was not significantly influenced by exposure to long-day photoperiod. We conclude that, in subtropical female goats that start lactation in late autumn, ex- posure to an artificial long-day photoperiod stimulates milk yield, even if goats are milked once daily. In addi- tion, combining exposure to long days with twice-daily milking will increase further milk yield in such goats without affecting milk components.

Whereas ewes initiate reproductive activity in response to a photoperiod signal initiated after the winter solstice of 35 long days (35 LD) followed by short days, the reproductive axis fails to respond to this signal between the autumn equinox and the winter solstice. The aim of experiment 1 was to determine whether the prolactin axis, like the reproductive axis, is unresponsive to a 35 LD photoperiod signal followed by continuous exposure to short days between the autumn equinox and the winter solstice. Whereas the 35 LD signal from September 21 (# 6 h increase in day length) failed to influence prolactin secretion, all other long-day treatments (. 6 h increase in day length) initiated a rise in prolactin in at least 75% of ewes in each group (p , 0.05). The aim of experiment 2 was to determine whether ewes failed to secrete prolactin during a 35 LD photoperiod from September 21 because they did not recognize a 6-h increase in day length at any time of year as a stimulatory photoperiod signal or because hypothalamic/pituitary regulation of prolactin synthesis or secretion is compromised in September. The results demonstrated that while hypothalamic regulation of prolactin secretion and pituitary stores of prolactin were normal at all times of year examined, the ability of ewes to secrete prolactin in response to a long-day photoperiod signal appears to be dependent on photoperiodic history rather than the time of year of the photoperiodic challenge.

Previous studies have shown that exposure to long days followed by short days after 12 wk of age advances the onset of puberty in ewe lambs. The aim of this experiment was to determine whether or not puberty would be advanced by exposure of lambs to such a photoperiodic regime when the long days were given before birth and the short days immediately after birth. Ewes kept in natural photoperiod (NP) were housed on January 15 and allocated at random to one of four treatments : 1) NP/NP, natural photoperiod before and after parturition (n = 26) ; 2) SD/SD, short days (SD ; 9L :15D) before and after parturition (n = 27) ; 3) LD/NP, long days (LD ; 18L :6D) before parturition and NP after parturition (n = 27) ; and 4) LD/SD, LD before parturition and SD after parturition (n = 26). Mean (± SEM) birth date for all lambs was March 20 ± 1 day, and the number of days of exposure to long and short days prior to parturition was 64 ± 2 and 67 ± 2 days, respectively. From ewes on the four treatments, 24, 20, 14, and 16 female lambs, respectively, were reared. Lambs were weighed at birth and at weekly intervals after weaning. Reproductive activity in ewe lambs was assessed from serum progesterone concentrations in blood samples collected twice weekly from August 1 until puberty was reached or the experiment terminated on November 17 (34 wk after birth). Time of puberty in lambs exposed to NP both before and after birth (24 of 24 lambs reached puberty on October 15 ± 4.0 days [mean ± SEM] ; 30 wk of age) was not different (p > 0.05) from that in lambs given LD before birth and NP after birth (14 of 14 lambs reached puberty on October 23 ± 3.3 days ; 31 wk of age). Puberty had not occurred at the end of the experiment (p < < 0.0001) in most lambs given SD after birth regardless of whether they were given SD or LD before birth (SD/SD, 5 of 20 lambs reached puberty with a mean puberty onset of October 27 ± 3.0 days [31.5 wk of age] ; LD/SD, 3 of 16 lambs reached puberty with a mean puberty onset of November 5 ± 9.0 days [33 wk of age]). Thus, exposure of pregnant ewes to LD before parturition did not advance puberty in their ewe lambs when exposed to NP or SD after birth. Exposure to short days after birth delayed puberty in most lambs. These results suggest that fetal lambs are unable to utilize long day photoperiodic cues given before birth to advance puberty in response to exposure to short days after birth and that photoperiod experienced after birth seems to be critical in timing puberty.

Studies of rodent photoperiodism have almost exclusively employed fixed photoperiods with abrupt shifts in day length (DL) of 4-8 h effected in a single day. Because DLs in nature change continuously and incrementally, rates of gonadal and somatic development were compared in the present study in hamsters exposed to gradually increasing vs. fixed DLs. Male hamsters gestated in 12 h light/day (12L) and exposed to DLs that increased gradually from 12L to 15.5L (experiment 1) or from 12L to 16L (experiment 2) weighed more and had larger gonads than did hamsters gestated and maintained from birth in a DL of absolutely greater duration (16L). Gradual increases in DL from 10L to 12L also resulted in more rapid somatic development than did gestation and maintenance in a static 12L photoperiod. The pattern of gradual increases in DL was not sufficient to accelerate development at all DLs but was effective in the range of 12L to 19L. Siberian hamsters are responsive to the pattern of photoperiodic change; the maximally stimulatory photoperiodic stimulus is not a fixed long day, but is instead increasing DLs, even those with absolutely shorter photophases; short gestational DLs potentiate the effects of longer postnatal DLs. The relations heretofore elaborated between fixed DLs and physiological responses differ from those obtained with more natural photoperiodic transitions.

Temperatures less than 21 degrees C suppressed the expression of autogeny in genetically autogenous females of Culex tarsalis Coquillett from Manitoba, even under a long day photoperiod of 16:8 (L:D). Under short day lengths (8:16), the percentage of autogenous females was suppressed at temperatures from 16 to 28 degrees C; but at 32 degrees C, maximum autogenous expression occurred. When genetically similar populations were maintained at 24 degrees C and exposed to photoperiods from 14:10 to 10:14 (L:D), autogeny was suppressed from a mean of 26% progressively to 1%. When all stages were maintained at 21 degrees C, pupae were photosensitive (i.e., the percentage of autogenous females was not affected by photoperiods at which larvae were maintained). The percentage of autogenous females in field populations followed the seasonal changes in temperature and photoperiod, demonstrating environmental regulation of facultative autogeny. Autogeny appeared to be genetically stable in Cx. tarsalis. Single families from a long standing laboratory colony (greater than 60 generations) had the same range (0-80%) in percentage of autogenous females per family as did recent field-collected families from the same geographical location.

Vegetative plants of the long-day grass Lolium temulentum L. Ceres were exposed to threshold long days or light breaks. Protracted darkness given just afterwards clearly promoted flowering and was weakly inductive on its own. The promotive effect of darkness was restricted to floral induction since further apical development was weak.

Six-week-old Lolium temulentum cv. Ceres plants were induced to flower by a single long day (Day 1). Cell proliferation was analysed in the apex during the period extending from Day 1 to Day 3. A stimulation of mitotic and DNA synthetic activities was observed in the apical summit at 8 h of the photoextension period of the LD, i.e. before any apparent movement of the floral stimulus out of the leaves and well in advance of apex evocation.

It is the end of a long day at the American Association for the Advancement of Science, in Washington, DC. The occasion has been a meeting of journal editors who work with Oxford University Press and discussion of new opportunities (and challenges) in journal publishing. As several new electronic features were discussed, I asked one of the OUP staff ‘‘How can we get these on the JDSDE homepage!’’ To my chagrin, she pointed out that they are already there. It seems that ‘‘behind the scenes,’’ OUP has been upgrading Web pages and offering new services that benefit readers, authors, and reviewers—and I never took/ had the time to notice. So, let me share some of the changes at Journal of Deaf Studies and Deaf Education (JDSDE), changes that you really do want to know about. For authors and reviewers, I am delighted to announce that beginning in September, JDSDE moved to an online submission and reviewing system known as Manuscript Central. Found at http:// mc.manuscriptcentral.com/jdsde, Manuscript Central will make manuscript processing more efficient for authors, reviewers, and editors. Most importantly, it should make the editorial process smoother and faster. JDSDE already has the best turnaround in our field, as the time from submission to editorial decision averages 7–8 weeks. If the system—and its users—work as planned, this should be reduced to 5–6 weeks, a real advantage for contributors and also for readers, who will be reading articles when they are still ‘‘hot’’ and timely. As someone who has been waiting 10 months for a review of an article from another journal, I believe that this change can only be good for the field. For everyone who has ever accessed the JDSDE either in print or electronically, our new and evolving Web page (www.jdsde.oxfordjournals.org; Figure 1) offers some exciting new features. The expanded capabilities of the site include six that I will outline here—hopefully enough to encourage readers to visit the site and explore the others.

The G2 line of peas ( Pisum sativum L.) displays senescence and death of the apical bud only in long days and in the presence of fruit. As the removal of fruit prevents senescence, one possible mechanism by which fruits induce senescence is that the fruits produce some `senescence factor9 under long day conditions, which is then transported to the apical bud. Allowing developing fruits to photosynthesize in the presence of 14 CO 2 results in the recovery of label in the apical bud. In order to determine the chemical nature of this radiolabeled material, fruits of G2 peas, growing under long days, were exposed to 14 CO 2 at the time when the first senescence symptoms start to appear. The radiolabeled material from apical buds was then extracted, purified, and identified. Using HPLC and GC-MS the major labeled compound found in the apical bud following exposure of pea fruits to 14 CO 2 was identified as sucrose, while malic acid was identified as the major ethyl acetate-soluble compound. These compounds accounted for about 73 and 16%, respectively, of the radioactivity in the apical bud. No other compounds were present in significant amounts. As neither of these chemicals is likely to have any kind of senescence effect, we report no evidence for a senescence factor.

Some exposure to long days (LD) is necessary for female sheep to achieve puberty during short days (SD). In this regard, a 5-wk block of long days in lambs otherwise raised in short days will result in puberty at the normal age. In the present study, Suffolk lambs were raised in various artificial photoperiods to assess the role of short days. An increase in circulating progesterone to luteal phase levels was used as the criterion for puberty. Controls exposed to short days except for S wk of long days between 17 and 22 wk (SD-LD-SD) began repetitive reproductive cycles at the expected age (34 ± 0. 7 wk, mean ± SE). When the final block of short days was eliminated and exposure to long days was continued after 22 wk of age (SD-LD-LD), puberty was delayed (41 ± 0.8 wk of age). Removal of the first block of short days (LD-LD-SD) did not prevent normal puberty, and the initiation of cycles (29 ± 0.9 wk) occurred earlier than in controls. Lambs in which the pineal gland was denervated at 22 wk so that it was unable to transduce short-day cues after exposure to long days (SD-LD-X) exhibited puberty at an age (33 ± 1.2 wk) similar to that of controls. The results indicate that a) neonatal exposure to short days is not necessary for subsequent recognition of long days; b) exposure to long days during the final stages of sexual maturation, rather than short days, delays puberty; and c) long day lengths set events into motion for normal puberty many weeks later, which can occur in the absence of additional photoperiod information about season. These combined findings raise the possibility that the short days of spring and autumn are largely permissive to the onset of puberty and that it is the long days of summer followed by their disappearance which times the initiation of reproductive cycles in spring-born lambs.

A laboratory breeding colony of Aedes dorsalis (Meigen) was used to test the roles of photoperiod and temperature on the direct induction of diapause in the embryonic stage. Induction of diapause was found to be dependent upon photoperiod. The critical photoperiod (50% diapause response) was 12.25:11.75 (h photo:scotophase). Temperature had no modifying effect upon the role of photoperiod throughout a constant temperature range of 5° to 20°C. The diapause inducing role of short photophase (long scotophase) was nullified by a constant 30°C temperature. There was no significant difference in response of incompletely and fully developed embryos to photoperiod. Diapause was terminated only under a combination of long day photophase and high temperature. The effect commenced after 24 h exposure and reached maximum response by 7 days.

The nature of long day inhibition of flowering in the short day plant Xanthium strumarium L. was studied by correlating the flowering response with the translocation of 14 C-assimilates from induced leaves or parts thereof to the shoot tips. In contrast to an earlier study by Gibby and Salisbury (Plant Physiol 1971 47: 784-789) no inhibitory effect of an immature leaf in long day on the flower-promoting effect of an induced leaf was detected. When the stimulus moved in the basipetal direction, mature leaves in long day were inhibitory to flowering and at the same time reduced the amount of 14 C-photosynthate that accumulated in the receptor buds. Inhibition of flowering was observed when the apical half of a single leaf was induced and the basal half kept under long day conditions. Induction of a lateral leaf half, with the other half remaining in long day, resulted in a normal flowering response. More 14 C-photosynthate was translocated to the shoot tip from the basal than from the apical leaf half. Removal of the noninduced basal leaf half except for the midrib and major veins, cutting the basal half along the midrib, or keeping the basal half in darkness, resulted in normal flowering. In all three treatments the amounts of 14 C-assimilates that accumulated in the shoot tips also increased, presumably because competing export of nonlabeled assimilates from the basal leaf halves was diminished or eliminated. Autoradiography indicated that 14 C-assimilates produced in the apical half were channeled through the basal half in the major veins and midrib to the petiole without partitioning back into the mesophyll. Since the veins and midrib in the basal half were by themselves not inhibitory to flowering, it is unlikely that the floral stimulus was inactivated in the long day tissue. When the basal half was labeled with 14 CO 2 , there was no indication in autoradiograms that 14 C-labeled assimilates moved in the blade in the apical direction. As a whole these results demonstrate that transmission of the floral stimulus and translocation of photosynthate are correlated, so that at least part of the long day inhibition in Xanthium can be explained in terms of translocation effects. However, the involvement of a transmissible inhibitor produced in long day tissue cannot be ruled out.

Least-squares models were fit to data from 216 experiments on the effects of decreasing photoperiod and fluctuating temperatures on diapause induction and termination in pink bollworm, Pectinophora gossypiella Saunders. The diapause induction model compared very favorably with field data collected from various locations in southern California and Arizona. The times required for termination of diapause in larvae reared from the diapause induction experiments increased under high fluctuating temperatures and short decreasing photoperiods, whereas long day length and low temperatures (within limits) decreased it. A model is proposed which links the results of the diapause induction and diapause termination studies and estimates the pattern of diapause termination the following spring.

Most vascular plants contain Delta(5)-sterols as the predominant type; however, a few species such as Medicago sativa, have mainly Delta(7)-sterols. The Delta(7)-sterols of alfalfa are isomers of the common Delta(5)-sterols and are generally assumed to be their immediate precursors. Light had a significant influence on the sterol status of M. sativa. High light intensity and a long day favored the accumulation of dihydrospinasterol; a short day and low light intensity, particularly darkness, favored spinasterol accumulation. These data for Delta(7)-sterol plants agree with those reported for Delta(5)-sterol plants; light favors the accumulation of the monounsaturated 29 carbon sterols and darkness favors the accumulation of the diunsaturated sterols. Proposed is a mechanism to explain the effect of light on the accumulation of Delta(7)- and Delta(5)-sterols.

Diapausing larvae of a laboratory strain of tufted apple budmoth, Platynota idaeusalis (Walker), were reared individually to larval-pupal ecdysis under different constant photoperiods and temperatures. Duration of larval instars 1 to 3 was not increased in diapausing insects (reared under short daylength) relative to nondiapausing larvae (reared under a long daylength), but there was a significant increase in duration of instars 4 and 5. Most of the increase in the number of days to larval-pupal ecdysis in diapausing insects occurred during additional larval instars of extended duration. Insects that diapaused under a 14-h daylength had significantly shorter times to larval-pupal ecdysis than those insects that diapaused under 10-, 11-, or 12-h daylength. At 10-h daylength, diapause duration and number of larval instars decreased with increasing temperature. Diapausing, field-collected larvae were reared to larval-pupal ecdysis under different photoperiods at 21°C. Diapause termination was spontaneous under both long and short days, and did not require chilling. Diapause duration was much shorter under long daylengths, and decreased under both long and short daylengths with later collection dates from autumn throught winter. Sensitivity to daylength was maintained through the end of winter; long day lengths apparently terminate diapause in the spring in field populations.

During the course of experiments on the metabolisnm of Kalanchoe in short and long days (5, 8,11 ) it was noticed that the leaves of plants induced to flower became red, especially at the apical end and on the underside. Nonflowering plants, i.e. those kept in long days, showed only slight and delayed reddening along the leaf margins. However, it was observed that when the leaves of plants on long day were boiled in HCl, a deep red color developed in the solution. This indicates presence of a leuco-anthocyanidin (1) and suggests that the photoperiod might be causing conversion of this compound to the red anthocyanin. Since the flowers whose formation is induced by exposure to short days are also bright red, it appeared further that the photoperiodic stimulus may exert a systemic effect which would lead to the formation of anthocyanin simultaneously in several parts of the plant. A detailed study was therefore made to determine: A, if the anthocyanins in flower and leaf were the same, or related, B, if the reaction is indeed a true response to photoperiod, C, the nature of the metabolic change involved. Although anthocyanins very commonly appear in the leaves of young growing shoots, especially of woody plants, and also in mature fully grown leaves (autumn colors) their appearance in leaves in direct association with flowering seems to have been less commonly noticed. It is not uncommon, however, for plants with red or blue flowers to develop anthocyanin in the midribs or petioles of the leaves, while those with white flowers do not.

Short photoperiods followed by low temperatures induced cold hardiness in Acer negundo, Viburnum plicatum tomentosum, and Weigela florida. Hardiness was also obtained under long days and natural fall temperatures if the leaves were removed, either manually or by low temperature. Similarly, removal of leaves from plants exposed to long days at 5 degrees brought about an accelerated rate of hardening. These observations suggested the presence of a hardiness inhibitor in the leaves which was counteracted by short days or removal of the leaves.

The responses of plants to varying photoperiod has received much attention since Garner and Allard (3, 4) first showed that flowering and fruiting of many plants is controlled by the relative length of day and night. Numerous species have been classified as "short day" or "long day" on the basis of the day length required for maximum flowering and fruiting. Temperature also may influence the flowering responses of plants (13), and the two factors may show interaction (11). The experiments with Kentucky bluegrass (Poa pratensis L.) reported here were conducted primarily for the purposes of studying the physiological response of this species to management practices which might influence forage and seed production (9t 10). The formation of flowers in May and June has placed this species in the "long-day'' class. However, Evans and Watkins (2) found that bluegrass plants produced inflorescenses in the spring regardless of length of day, and none was reported in the fall under day lengths ranging from 8.5 to 18 hours. Since plants are dependent upon their leaves for both the stimulus of photoperiod (5, ?) and reserve accumulations, any cultural treatments such as close grazing or clipping of Kentucky bluegrass could influence subsequent seed production, either through induction or through subsequent development of flowers and fruits. An interaction of nitrogen fertilization with photoperiod also was found in studies reported by Borthwick (1).

Two basic experiments defined a long-day inhibitory effect on Xanthium flowering: the basal half of a single leaf on long day inhibits response of the tip half to a short day; and a long-day leaf inhibits response of a short-day leaf, providing it is between the short-day leaf and a receptive bud (whether above or below the short-day leaf). Five hypotheses were explored with the conclusions that the tip half can synthesize florigen, and inhibition is not due to prevention of florigen synthesis, translocational effects, or a translocatable long-day inhibitor. Inhibition is localized and may be a condition of the leaf or a relatively immobile substance. Studies of critical dark period, light intensity, and interruption of a dark period show that, when the leaf is not producing florigen, it is actively inhibitory. Immature leaves are more inhibitory than older leaves. The effect was found not to pass dead tissue, and iron-deficient tissue will cause inhibition, though it will not cause promotion.

Field and laboratory experiments showed that under certain conditions adult females of the predator Jalysus spinosus (Say) have a facultative reproductive diapause in North Carolina. Diapausing females appeared in the Oxford, NC area in late August, as day length declined to 13.5h and less. In the laboratory at 26.7°C, the percentage incidence of diapause rose abruptly from ca. 9% at 13.5 photophase to 98% at 12.5 h. The diapause-induction curve was a Type III shape, with 0% diapause at constant darkness. A long day (14 h light and 10 h dark) and warmer temperatures shortened the length of diapause.

GA 3 and cyclic AMP induce floral buds in Eschscholtzia californica under noninductive short days and hasten it under inductive long day conditions.