@article{villavicencio_blankenship_yencho_thomas_raper_2007, title={Temperature effect on skin adhesion, cell wall enzyme activity, lignin content, anthocyanins, growth parameters, and periderm histochemistry of sweetpotato}, volume={132}, number={5}, journal={Journal of the American Society for Horticultural Science}, author={Villavicencio, L. E. and Blankenship, S. M. and Yencho, G. C. and Thomas, J. F. and Raper, C. D.}, year={2007}, pages={729–738} }
 @article{thomas_pline-srnic_thomas_edmisten_wells_wilcut_2004, title={Glyphosate negatively affects pollen viability but not pollination and seed set in glyphosate-resistant corn}, volume={52}, ISSN={["1550-2759"]}, DOI={10.1614/WS-03-134R}, abstractNote={Abstract Experiments were conducted in the North Carolina State University Phytotron greenhouse and field locations in Clayton, Rocky Mount, and Lewiston-Woodville, NC, in 2002 to determine the effect of glyphosate on pollen viability and seed set in glyphosate-resistant (GR) corn. Varieties representing both currently commercial GR corn events, GA21 and NK603, were used in phytotron and field studies. All glyphosate treatments were applied at 1.12 kg ai ha−1 at various growth stages. Regardless of hybrid, pollen viability was reduced in phytotron and field studies with glyphosate treatments applied at the V6 stage or later. Scanning electron microscopy of pollen from affected treatments showed distinct morphological alterations correlating with reduced pollen viability as determined by Alexander stain. Transmission electron microscopy showed pollen anatomy alterations including large vacuoles and lower starch accumulation with these same glyphosate treatments. Although pollen viability and pollen production were reduced in glyphosate treatments after V6, no effect on kernel set or yield was found among any of the reciprocal crosses in the phytotron or field studies. There were also no yield differences among any of the hand self-pollinated (nontreated male × nontreated female, etc.) crosses. Using enzyme-linked immunosorbent assay to examine CP4-5-enolpyruvlshikimate-3-phosphate synthase expression in DKC 64-10RR (NK603) at anthesis, we found the highest expression in pollen with progressively less in brace roots, ear leaf, anthers, roots, ovaries, silks, stem, flag leaf, and husk. Nomenclature: Glyphosate; corn, Zea mays L.; ‘DK 662RR’; ‘DK 687RR’; ‘DKC 64-10RR/SIL’.}, number={5}, journal={WEED SCIENCE}, author={Thomas, WE and Pline-Srnic, WA and Thomas, JF and Edmisten, KL and Wells, R and Wilcut, JW}, year={2004}, pages={725–734} }
 @article{chiera_thomas_rufty_2004, title={Growth and localized energy status in phosphorus-stressed soybean}, volume={27}, ISSN={["1532-4087"]}, DOI={10.1081/LPLA-200030007}, abstractNote={Abstract In plants experiencing phosphorus (P) stress, ATP concentrations can be reduced significantly and shoot growth is strongly restricted, raising the possibility that energy availability is responsible for the growth inhibition. Experiments were conducted to investigate the relationship between P deprivation and energy availability in tissues involved in the growth response. Young soybean (Glycine max [L.] Merr. cv. Ransom) plants were deprived of P for 32 days. Leaf initiation and individual leaf expansion were followed along with localized P and ATP concentrations. Tissue analyses revealed preferential distribution of P to the root, which accompanied a decline in the shoot to root dry weight ratio. Even though P concentrations in all shoot tissues dropped sharply, ATP concentrations and energy charge in the shoot meristem region were maintained similar to controls for an extended period when leaf initiation slowed. In the first trifoliolate leaf, ATP and energy charge remained at control levels during the expansion phase, but expansion was inhibited by 50%. Furthermore, ATP levels in root tips were decreased almost 30%, yet growth of the root system was equal to or greater than the control. The absence of a positive correlation between ATP levels and growth responses in the different tissues suggests that energy availability is not a primary factor limiting growth under P stress conditions. The results, along with others from previous experiments, support the notion that a signaling mechanism, as yet unidentified, controls down regulation of cell division in shoot growth regions.}, number={11}, journal={JOURNAL OF PLANT NUTRITION}, author={Chiera, JM and Thomas, JF and Rufty, TW}, year={2004}, pages={1875–1890} }
 @article{pline_edmisten_wilcut_wells_thomas_2003, title={Glyphosate-induced reductions in pollen viability and seed set in glyphosate-resistant cotton and attempted remediation by gibberellic acid (GA(3))}, volume={51}, ISSN={["0043-1745"]}, DOI={10.1614/0043-1745(2003)051[0019:GIRIPV]2.0.CO;2}, abstractNote={Abstract Glyphosate treatments to glyphosate-resistant (GR) cotton can cause increased fruit loss compared with untreated plants, likely due to reductions in pollen viability and alterations in floral morphology that may reduce pollination efficiency. This study was conducted to determine whether both stamen and pistil are affected by glyphosate treatments by measuring seed set from reciprocal reproductive crosses made between glyphosate-treated GR, untreated GR, and conventional nontransgenic cotton. Pollen viability was 51 and 38% lower for the first and second week of flowering, respectively, in GR plants treated with a four-leaf postemergence (POST) treatment and an eight-leaf POST-directed treatment of glyphosate than in GR plants that were not treated. Seed set per boll was significantly reduced when the pollen donor parent was glyphosate treated vs. untreated for the first 2 wk of flowering. There were no significant differences between treatments applied to male parents as measured by seed set at Weeks 3 and 4 of flowering. Seed set was not influenced by glyphosate treatments applied to female parents at any time. Retention of bolls resulting from crosses was reduced by glyphosate treatment of male parents during the first and third week of flowering but was not affected by glyphosate treatment of female parents. The application of gibberellic acid (GA), which has been shown to reverse male sterility in tomato (Lycopersicon esculentum L.) and to enhance boll retention in cotton, was investigated for similar effects in glyphosate-treated GR cotton. The GA treatments to glyphosate-treated plants increased the anther–stigma distance 12-fold, stigma height, and pollen viability in the second week of flowering but decreased the number of seeds in second-position bolls on Fruiting branches 1 through 3, decreased the number of first-position bolls per plant, and increased the number of squares in comparison with glyphosate-treated GR plants not receiving GA. Although GA applications to glyphosate-treated GR cotton have some remedial effect on pollen viability, the GA-induced increase in the anther–stigma difference exacerbates the increase in anther–stigma distance caused by glyphosate, resulting in low pollination. Nomenclature: Glyphosate; cotton, Gossypium hirsutum L. ‘Delta Pine & Land 5415RR’, ‘Delta Pine & Land 5415’.}, number={1}, journal={WEED SCIENCE}, author={Pline, WA and Edmisten, KL and Wilcut, JW and Wells, R and Thomas, J}, year={2003}, pages={19–27} }
 @article{sato_peet_thomas_2002, title={Determining critical pre- and post-anthesis periods and physiological processes in Lycopersicon esculentum Mill. exposed to moderately elevated temperatures}, volume={53}, ISSN={["0022-0957"]}, DOI={10.1093/jexbot/53.371.1187}, abstractNote={To determine the thermosensitive periods and physiological processes in tomato flowers exposed to moderately elevated temperatures, tomato plants (Lycopersicon esculentum Mill., cv. NC 8288) were grown at 28/22 degrees C or 32/26 degrees C day/night temperature regimes and then transferred to the opposite regime for 0-15 d before or 0-24 h after anthesis. For plants initially grown at 28/22 degrees C, moderate temperature stress before anthesis decreased the percentage of fruit set per plant, but did not clarify the thermosensitive period. The same level of stress did not significantly reduce fruit set when applied immediately after anthesis. For plants initially grown at 32/26 degrees C, fruit set was completely prevented unless a relief period of more than 5 d was provided before anthesis. The same level of stress relief for 3-24 h after anthesis also increased fruit set. Plants were most sensitive to 32/26 degrees C temperatures 7-15 d before anthesis. Microscopic investigation of anthers in plants grown continuously at high temperature indicated disruption of development in the pollen, endothecium, epidermis, and stomium. This disruption was reduced, but still observable in plants relieved from high temperature for 10 d before anthesis.}, number={371}, journal={JOURNAL OF EXPERIMENTAL BOTANY}, author={Sato, S and Peet, MM and Thomas, JF}, year={2002}, month={May}, pages={1187–1195} }
 @article{chiera_thomas_rufty_2002, title={Leaf initiation and development in soybean under phosphorus stress}, volume={53}, ISSN={["0022-0957"]}, DOI={10.1093/jexbot/53.368.473}, abstractNote={Experiments investigated changes in leaf development in young soybean plants progressing into P stress. The apical meristem and leaf structure were examined anatomically to evaluate the involvement of cell division and cell expansion in the restriction of leaf number and individual leaf size. Seedlings were deprived of P for 32 d following germination. Leaf initiation rates declined noticeably after about 2 weeks, even though the apical dome was of similar size and had a similar number of cells as controls. Primordia appeared morphologically similar also. Expansion of primary and the first three trifoliolate leaves of -P plants was severely reduced, and expansion of each leaf ceased, uniformly, when an area of about 40 cm(2) was obtained. Leaf epidermal cell size in the lateral plane was unaffected. The results indicate that expansion of leaves under P stress was limited by the number of cell divisions, which would imply control of cell division by a common regulatory factor within the leaf canopy.}, number={368}, journal={JOURNAL OF EXPERIMENTAL BOTANY}, author={Chiera, J and Thomas, J and Rufty, T}, year={2002}, month={Mar}, pages={473–481} }
 @article{pline_viator_wilcut_edmisten_thomas_wells_2002, title={Reproductive abnormalities in glyphosate-resistant cotton caused by lower CP4-EPSPS levels in the male reproductive tissue}, volume={50}, ISSN={["0043-1745"]}, DOI={10.1614/0043-1745(2002)050[0438:RAIGRC]2.0.CO;2}, abstractNote={Abstract Glyphosate treatments to glyphosate-resistant (GR) cotton have been associated with poor pollination and increased boll abortion. Anatomical studies were conducted to characterize the effect of glyphosate treatments on the development of male and female reproductive organs of cotton flowers at anthesis. In comparison with nontreated plants, glyphosate applied at both the four-leaf stage postemergence (POST) and at the eight-leaf stage POST directed inhibited the elongation of the staminal column and filament, which increased the distance from the anthers to the receptive stigma tip by 4.9 to 5.7 mm during the first week of flowering. The increased distance from the anthers to the stigma resulted in 42% less pollen deposited on stigmas of glyphosate-treated plants than in nontreated plants. Moreover, pollen from glyphosate-treated plants showed numerous morphological abnormalities. Transmission electron microscopy showed the presence of large vacuoles, numerous starch grains, and less organized pockets of the endoplasmic reticulum containing fewer ribosomes in pollen from glyphosate-treated plants than from nontreated plants. Pollen development in glyphosate-treated plants is likely inhibited or aborted at the vacuolate microspore and vacuolate microgamete stages of microgametogenesis, resulting in immature pollen at anthesis. Although stigmas from glyphosate-treated plants were 1.2 to 1.4 mm longer than those from nontreated plants, no other anatomical differences in stigmas were visibly evident. The presence of the GR 5-enolpyruvylshikimate-3-phosphate synthase (CP4-EPSPS) enzyme from Agrobacterium sp. strain CP4 was quantified in reproductive and vegetative tissues using enzyme-linked immunosorbent assay. The content of CP4-EPSPS in the stigma, anther, preanthesis floral bud (square), and flower petals was significantly less than that in the vegetative leaf tissue. Glyphosate effects on the male reproductive development resulting in poor pollen deposition on the stigma, as well as production of aborted pollen with reduced viability, provide a likely explanation for reports of increased boll abortion and pollination problems in glyphosate-treated GR cotton. Nomenclature: Glyphosate; cotton, Gossypium hirsutum L. ‘Delta Pine & Land 5415RR’, ‘Delta Pine & Land 50’, ‘Delta Pine & Land 90’, ‘SureGrow 125RR’.}, number={4}, journal={WEED SCIENCE}, author={Pline, WA and Viator, R and Wilcut, JW and Edmisten, KL and Thomas, J and Wells, R}, year={2002}, pages={438–447} }
 @article{koltai_dhandaydham_opperman_thomas_bird_2001, title={Overlapping plant signal transduction pathways induced by a parasitic nematode and a rhizobial endosymbiont}, volume={14}, ISSN={["0894-0282"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0034800333&partnerID=MN8TOARS}, DOI={10.1094/MPMI.2001.14.10.1168}, abstractNote={ Root-knot nematodes and rhizobia establish interactions with roots characterized by the de novo induction of host structures, termed giant cells and nodules, respectively. Two transcription regulators, PHAN and KNOX, required for the establishment of meristems were previously shown to be expressed in tomato giant cells. We isolated the orthologues of PHAN and KNOX (Mt-phan and Mt-knox-1) from the model legume Medicago truncatula, and established the spatial distribution of their expression in situ. We confirmed that Mt-phan and Mt-knox-1 are expressed in lateral root initials and in nematode-induced giant cells and showed that they are expressed in nodules induced by Sinorhizobium meliloti. Expression of both genes becomes spatially restricted as the nodules develop. We further examined nematode feeding sites for the expression of two genes involved in nodule formation, ccs52 (encodes a mitotic inhibitor) and ENOD40 (encodes an early, nodulation mitogen), and found transcripts of both genes to be present in and around giant cells induced in Medicago. Collectively, these results reveal common elements of host responses to mutualistic and parasitic plant endosymbionts and imply that overlapping regulatory pathways lead to giant cells and nodules. We discuss these pathways in the context of phytohormones and parallels between beneficial symbiosis and disease. }, number={10}, journal={MOLECULAR PLANT-MICROBE INTERACTIONS}, author={Koltai, H and Dhandaydham, M and Opperman, C and Thomas, J and Bird, D}, year={2001}, month={Oct}, pages={1168–1177} }
 @article{sato_peet_thomas_2000, title={Physiological factors limit fruit set of tomato (Lycopersicon esculentum Mill.) under chronic, mild heat stress}, volume={23}, ISSN={["1365-3040"]}, DOI={10.1046/j.1365-3040.2000.00589.x}, abstractNote={ABSTRACT}, number={7}, journal={PLANT CELL AND ENVIRONMENT}, author={Sato, S and Peet, MM and Thomas, JF}, year={2000}, month={Jul}, pages={719–726} }
 @article{washburn_thomas_2000, title={Reversion of flowering in Glycine max (Fabaceae)}, volume={87}, ISSN={["1537-2197"]}, DOI={10.2307/2656869}, abstractNote={Photoperiodic changes, if occurring before a commitment to flowering is established, can alter the morphological pattern of plant development. In this study, Glycine max (L.) Merrill cv. Ransom plants were initially grown under an inductive short‐day (SD) photoperiod to promote flower evocation and then transferred to a long‐day (LD) photoperiod to delay flower development by reestablishing vegetative growth (SD–LD plants). Some plants were transferred back to SD after 4‐LD exposures to repromote flowering (SD–LD–SD plants). Alterations in organ initiation patterns, from floral to vegetative and back to floral, are characteristic of a reversion phenomenon. Morphological features that occurred at the shoot apical meristem in SD, LD, SD–LD, and SD–LD–SD plants were observed using scanning electron microscopy (SEM). Reverted plants initiated floral bracts and resumed initiation of trifoliolate leaves in the two‐fifths floral phyllotaxy prior to terminal inflorescence development. When these plants matured, leaf‐bract intermediates were positioned on the main stem instead of trifoliolate leaves. Plants transferred back to a SD photoperiod flowered earlier than those left in LD conditions. Results indicated that in plants transferred between SDs and LDs, photoperiod can influence organ initiation in florally evoked, but not committed, G. max plants.}, number={10}, journal={AMERICAN JOURNAL OF BOTANY}, author={Washburn, CF and Thomas, JF}, year={2000}, month={Oct}, pages={1425–1438} }
 @article{thomas_kanchanapoom_1991, title={SHOOT MERISTEM ACTIVITY DURING FLORAL TRANSITION IN GLYCINE-MAX (L) MERR}, volume={152}, ISSN={["0006-8071"]}, DOI={10.1086/337873}, abstractNote={The soybean (Glycine max [L.] Merr.) is a quantitative short-day (SD) plant requiring two inductive cycles for floral initiation, which occurs first in the most undifferentiated meristem in an axil of a main stem leaf. Floral initiation at the main stem apex, however, requires additional SD inductive cycles. Under continuous SD the transition to flowering in the main stem apex is completed after 8 SD cycles. Differentiation and organogenesis of the first flower in the terminal raceme is apparent after 10 SD cycles. The changes in apical size and geometry, nuclear DNA, and rate of leaf initiation were followed daily during this 10-d period and compared with apices from plants kept under noninductive long days (LD). At emergence all plants had initiated three trifoliolate leaf primordia and during the vegetative stage of development maintained a plastochron of 2.0 d/leaf. The plastochron was shortened to 1.0 d/leaf in SD plants on day 7, just prior to the end of the transition. Apical size and geometry remained unchanged until after 6 SD cycles when height of the dome decreased and there was less elongation of the rib meristem. Earlier events included significantly lower amounts of nuclear DNA in cells of SD apices after 1 and 3 SD cycles. Later, the amount of nuclear DNA increased in cells of SD apices beginning after 5 SD and peaking after 6 SD before decreasing back to control levels. Shifts in increasing proportions of the population of nuclei from the 4C to 2C condition occurred after 1 SD and 3 SD. As in other species, both of these shifts are apparently essential components for the floral transition at the shoot apex in soybean. The first shift, or "mitotic" stimulus, signals that the process of the floral transition has begun, while the second shift, or "floral" stimulus, is required for completion of the process.}, number={2}, journal={BOTANICAL GAZETTE}, author={THOMAS, JF and KANCHANAPOOM, ML}, year={1991}, month={Jun}, pages={139–147} }
 @article{thomas_kanchanapoom_1990, title={MERISTEMATIC ACTIVITY AND LEAF INITIATION IN THE SHOOT APEX OF NICOTIANA-TABACUM DURING FLORAL TRANSITION}, volume={151}, ISSN={["0006-8071"]}, DOI={10.1086/337828}, abstractNote={Meristematic activity in shoot apices of NCTG-22, a short-day (SD) sensitive cultivar of Nicotiana tabacum, was monitored throughout the 17-d period of transition from vegetative to reproductive growth The analysis included changes in (1) size of the apical meristem, (2) rate of leaf initiation, (3) amount of nuclear DNA, and (4) percentage of cells in division. Plants grown in controlled environment chambers set at 26/22 C day/night temperatures were exposed either to an inductive short-day photoperiod or a noninductive long-day (LD) photoperiod after a 6-wk juvenile period. The first morphological change associated with floral onset was an acceleration in the rate of leaf initiation following three inductive cycles, which continued and resulted in the eventual production of three more leaves by SD plants than by vegetative LD plants Apices were identical in size until seven inductive cycles were completed, after which SD apices began to enlarge, finally becoming more than twice as wide as LD apices and assuming a domed shape. At the cellular level the percentage of cells in division increased in SD apices after one inductive cycle and generally remained significantly higher (1%-2.5%) than in LD apices during the entire transition period. A majority of the population of cells in LD apices favored the G1 condition. After exposure to one and three SD cycles, however, 12%-14% more cells were in the G1 phase in SD apices than in LD. During SDs 8-15, concurrent with dome enlargement, 10%-26% more cells again were in G1 than in LD apices. These results and previous observations on the floral transition in Nicotiana suggest that there may be two different processes controlling meristematic activity during two different phases of the transition period.}, number={3}, journal={BOTANICAL GAZETTE}, author={THOMAS, JF and KANCHANAPOOM, ML}, year={1990}, month={Sep}, pages={285–292} }