Geographical Transition of Sylleptic/Proleptic Branching in Three Cinnamomum Species with Different Bud Types

Three native Japanese Cinnamomum(Lauraceae) species exhibiteither sylleptic and proleptic, or proleptic branching dependingon species-specific types of bud-structure (hypsophyllary andscaled-buds) and geographical distribution. Major branchingshifted from sylleptic at the axils of cataphylls and hypsophyllsin the southernmost C. doederleinii(latitudinal distributionrange 24–28° N) to both sylleptic at cataphyllary-and proleptic at hypsophyllary-axils in mid-latitudinal C. daphnoides(27–33°N), and to proleptic at the axils of foliage-leaves in the northernmostspecies C. japonicum(25–37° N). In all three Cinnamomumspecies, the sylleptic and proleptic branches expand aroundthe boundary between two successive yearly shoot-modules. Thepredominant, fertile axils having branches shifted from cataphylls(n year) and hypsophylls (n-1 year) in C. doederleinii and C.daphnoides, to foliage-leaves (n-1) in C. japonicum. The budsof proleptic branches at the axils of hypsophylls and foliage-leavesinevitably experience winter dormancy, hence the shoots areequipped with protective cataphylls instead of a hypopodium.Shoot length and leaf number gradually increased from the mostdistal cataphyllary sylleptic (n) shoots towards the most basalproleptic shoots at the axils of foliage-leaves (n-1). Prolepticshoots at the axils of foliage-leaves perform similarly to mainshoots in all three Cinnamomum species studied. The relativenumber of leaves borne on proleptic shoots gradually increasedfrom C. doederleinii, to C. daphnoides, and C. japonicum. Underthe seasonal, short growing periods of temperate latitudes,the increased shoot performance and bud protection of prolepticshoots are made possible through the earlier onset of bud formation(prolepsis) at the axils of the previous year's hypsophyllsand/or foliage-leaves in trees with rhythmic growth. Copyright2001 Annals of Botany Company Syllepsis, prolepsis, bud type, cataphyll, hypsophyll, shoot-growth cycle, evergreen broad-leaved tree, Cinnamomum doederleinii, Cinnamomum daphnoides, Cinnamomum japonicum     

Auxin and cytokinin related gene expression during active shoot growth and latent bud paradormancy in Vitis riparia grapevine

Cultural practices for canopy management in grapevines rely on intensive manipulation of shoot architecture to maintain canopy light levels. In contrast to common model plant systems used to study regulation of branch outgrowth, the grapevine has a more complex architecture. The node contains first, second and third order axillary meristems. The prompt bud (N+1) develops into a summer lateral and a latent compound bud develops in the basal node of the summer lateral (N+2, N+3(1,2)). The outgrowth potential of latent buds was determined using common canopy management treatments (shoot tip decapitation and removal of summer laterals and leaves) and monitoring the rate of latent bud outgrowth. Two shoot node regions (apical and basal) with differential outgrowth potential were characterized and it was noted that the shoot tip, summer laterals and leaves in addition to node position contributed to the inhibition of latent bud outgrowth. To advance the understanding of the molecular regulation of bud outgrowth and paradormancy in the complex shoot architecture of grapevines, the expression of auxin and cytokinin genes involved in branching (amidase (VrAMI1), PINFORMED-3 (VrPIN3) and isopentenyl transferase (VrIPT)) were monitored in shoot tips and differentially aged buds of Vitis riparia grapevine shoots. In addition, Histone 3 (VrH3) and a hexose transporter (VrHT1) expression were monitored as a measure of tissue activity. The expression of VrAMI1 and VrPIN3 remained constant in actively growing shoot tips and decreased significantly with increasing bud maturation in paradormant buds. VrHT1 expression was greater in buds than in any other plant tissue tested. VrHT1 may have the potential to be used as an indicator of paradormancy status in grapevines. These characterizations in the complex architecture of the grapevine provide an excellent model system for molecular analysis of bud outgrowth and shoot architecture development.     

Hormones and Apical Dominance in the Fern Davallia

Lateral buds of the fern Davallia trichomanoides are releasedfrom inhibition by the removal of the main shoot apex. However,auxin is not capable of substituting for the apex in decapitatedshoots nor can auxin in shoot tips be detected by bioassay orextraction and chromatography. Expanding leaves of this speciescontain auxin, but these organs are not responsible for inhibitionof lateral bud growth. The response of lateral buds to an exogenouslyapplied cytokinin does not result in initial bud break. It isconcluded that the hormonal factors known to govern apical dominancein seed plants are not responsible for the regulation of differentialbud expansion in this fern.     

Effect of Assimilate Supply on Development and Growth Potential of Axillary Buds in Roses

The effect of assimilate supply on axillary bud developmentand subsequent shoot growth was investigated in roses. Differencesin assimilate supply were imposed by differential defoliation.Fresh and dry mass of axillary buds increased with increasedassimilate supply. The growth potential of buds was studiedeither by pruning the parent shoot above the bud, by graftingthe bud or by culturing the bud in vitro. Time until bud breakwas not clearly affected by assimilate supply during bud development,Increase in assimilate supply slightly increased the numberof leaves and leaf primordia in the bud; the number of leavespreceding the flower on the shoot grown from the axillary budsubstantially increased. No difference was found in the numberof leaves preceding the flower on shoots grown from buds attachedto the parent shoot and those from buds grafted on a cutting,indicating that at the moment of release from inhibition thebud meristem became determined to produce a specific numberof leaves and to develop into a flower. Assimilate supply duringaxillary bud development increased the number of pith cells,but the final size of the pith in the subsequent shoot was largelydetermined by cell enlargement, which was dependent on assimilatesupply during shoot growth. Shoot growth after release frominhibition was affected by assimilate supply during axillarybud development only when buds sprouted attached to the parentshoot, indicating that shoot growth is, to a major extent, dependenton the assimilate supply available while growth is taking place.Copyright1994, 1999 Academic Press Assimilate supply, axillary bud, cell number, cell size, defoliation, development, growth potential, meristem programming, pith, Rosa hybrida, rose, shoot growth     

Apical Dominance Control in Ipomoea nil: The Influence of the Shoot Apex, Leaves and Stem

The outgrowth of lateral buds is known to be controlled by theupper shoot tissues, which include the apex, the young leavesand the upper stem. An analysis of the influence of these plantparts on axillary bud elongation in Ipomoea nil was carriedout by various treatments on these specific tissues. A restriction of elongation in the main shoot due to eitherdecapitation or shoot inversion resulted in the release of apicaldominance A non-linear type of compensating growth relationshipwas observed between the 13 cm apical growing region of thestem and the lateral buds. It was determined by decapitation,defoliation and AgNO₃ treatments that both the 13 cm stem-growthregion and the young leaves (1–5 cm in length) had a muchgreater inhibitory influence on the outgrowth of specified lateralbuds than did the stem apex (consisting of the terminal 0.5cm of the shoot). The specified lateral buds which were analyzedfor outgrowth were located a number of nodes below the shootapex. The intervening nodes were debudded. Although the importanceof young leaves in the control of apical dominance has beenpreviously recognized, the most significant result from thepresent study with Ipomoea was the strong influence of the 13cm apical growth region of the stem on the out growth of thelateral buds. Apical dominance, Ipomoea nil L., Pharbitis nil, growth region, lateral bud outgrowth, decapitation, defoliation, shoot inversion     

Growth Context and Fate of Axillary Meristems of Young Peach Trees. Influence of Parent Shoot Growth Characteristics and of Emergence Date

The relationship between several growth components of a shootand the fates of the axillary meristems (developing in the axilsof the leaves) borne by that shoot were studied, on first-ordershoots of young peach trees. A comprehensive picture of thoserelationships was obtained by a discriminant analysis. Shootgrowth at meristem emergence date was characterized by internodelength, leaf-production rate and leaf-unfolding duration. Allpossible fates of axillary meristems at the end of the growingseason (i.e. blind nodes, single vegetative or flower bud, budassociations, sylleptic or proleptic shoots) were considered.Shoot-elongation rate determined meristem fates quantitatively.The number of buds produced by a meristem increased when theshoot-elongation rate increased. Qualitatively, the fate of axillary meristems was related tothe balance between shoot-growth components. If the subtendingleaf unfolded slowly, sylleptic or proleptic shoots were morelikely to develop than bud associations, for high shoot-elongationrates; and flower buds were more frequent than vegetative buds,for low shoot-elongation rates. Compared to flower buds, blindnodes appeared for similar shoot-elongation rates but longerinternodes and lower leaf-production rates. The emergence dateslightly modified the relation between shoot growth and axillary-meristemfates, but the main features held true throughout the growingseason. The relationships between shoot growth and meristem fates mayresult from competitive interactions between the growing subtendingleaf and the developing axillary meristem. Growing conditionsmight also influence both shoot growth and meristem fates byfavouring either cell enlargement or cell division.Copyright1995, 1999 Academic Press Peach tree, Prunus persica (L.) Batsch, axillary meristem, meristem fate, branching, flowering, shoot growth, discriminant analysis, exploratory analysis     

Bud Structure in Relation to Shoot Morphology and Position on the Vegetative Annual Shoots of Juglans regia L. (Juglandaceae)

The length and basal diameter of all lateral and terminal budsof vegetative annual shoots of 7-year-oldJuglans regia treeswere measured. All buds were dissected and numbers of cataphylls,embryonic leaves and leaf primordia were recorded. Each axillarybud was ranked according to the position of its associated leaffrom the apex to the base of its parent shoot. Bud size andcontent were analysed in relation to bud position and were comparedwith the size and number of leaves of shoots in equivalent positionswhich extended during the following growing season. Length andbasal diameter of axillary buds varied according to their positionon the parent shoot. Terminal buds contained more embryonicleaves than any axillary bud. The number of leaves was smallerfor apical and basal axillary buds than for buds in intermediatepositions on the parent shoot only. All new extended shootswere entirely preformed in the buds that gave rise to them.Lateral shoots were formed in the median part of the parentshoot. These lateral shoots derived from buds which were largerthan both apical and basal ones. Copyright 2001 Annals of BotanyCompany Juglans regia L., Persian walnut tree, branching pattern, preformation, bud content, shoot morphology     

Bud Content and its Relation to Shoot Size and Structure in Nothofagus pumilio(Poepp. et Endl.) Krasser (Nothofagaceae)

Buds of shoots from the trunk, main branches, secondary branchesand short branches of 10–21 year-old Nothofagus pumiliotrees were dissected and their contents recorded. The numberof differentiated nodes in buds was compared with the numberof nodes of sibling shoots developed at equivalent positionsduring the following growing season. Axillary buds generallyhad four cataphylls, irrespective of bud position in the tree,whereas terminal buds had up to two cataphylls. There were morenodes in terminal buds, and the most distal axillary buds, oftrunk shoots than in more proximal buds of trunk shoots, andin all buds of shoots at all other positions. The highest numberof nodes in the embryonic shoot of a bud varied between 15 and20. All shoots had proximal lateral buds containing an embryonicshoot with seven nodes, four with cataphylls and three withgreen leaf primordia. The largest trunk, and main branch, shootswere made up of a preformed portion and a neoformed portion;all other shoots were entirely preformed. In N. pumilio, theacropetally-increasing size of the sibling shoots derived froma particular parent shoot resulted from differences in: (1)the number of differentiated organs in the buds; (2) the probabilityof differentiation of additional organs during sibling shootextension; (3) sibling shoot length; (4) sibling shoot diameter;and (5) the death of the apex and the most distal leaves ofeach sibling shoot. Copyright 2000 Annals of Botany Company Axis differentiation, branching, bud structure, leaf primordia, neoformation, Nothofagus pumilio, preformation, size gradient     

Development and Growth Potential of Axillary Buds in Roses as Affected by Bud Age

The effect of axillary bud age on the development and potentialfor growth of the bud into a shoot was studied in roses. Ageof the buds occupying a similar position on the plant variedfrom 'subtending leaf just unfolded' up to 1 year later. Withincreasing age of the axillary bud its dry mass, dry-matterpercentage and number of leaves, including leaf primordia, increased.The apical meristem of the axillary bud remained vegetativeas long as subjected to apical dominance, even for 1 year. The potential for growth of buds was studied either by pruningthe parent shoot above the bud, by grafting the bud or by culturingthe bud in vitro. When the correlative inhibition (i.e. dominationof the apical region over the axillary buds) was released, additionalleaves and eventually a flower formed. The number of additionalleaves decreased with increasing bud age and became more orless constant for axillary buds of shoots beyond the harvestablestage, while the total number of leaves preceding the flowerincreased. An increase in bud age was reflected in a greaternumber of scales, including transitional leaves, and in a greaternumber of non-elongated internodes of the subsequent shoot.Time until bud break slightly decreased with increasing budage; it was long, relatively, for 1 year old buds, when theysprouted attached to the parent shoot. Shoot length, mass andleaf area were not clearly affected by the age of the bud thatdeveloped into the shoot. With increasing bud age the numberof pith cells in the subsequent shoot increased, indicatinga greater potential diameter of the shoot. However, final diameterwas dependent on the assimilate supply after bud break. Axillarybuds obviously need a certain developmental stage to be ableto break. When released from correlative inhibition at an earlierstage, increased leaf initiation occurs before bud break.Copyright1994, 1999 Academic Press Age, axillary bud, cell number, cell size, pith, shoot growth, Rosa hybrida, rose     

The Effect of Chemical Defoliation on the Development of Apple Spurs

An analysis was made of bud development on apple spurs sprayedwith copper sulphate in late spring. The treatments caused thespur buds to break into a second flush of growth and eventuallyto form a new resting bud. The failure of these later buds tobecome fruit buds was correlated with the time in the seasonwhen they began to form, and was determined by the number ofleaves and bud scales preceding the buds. The number of leavesin the second flush was related to the extent to which shoottips and spurs were killed by the sprays; the number of leavesin the first flush and the number of bud-scales between theseflushes of growth was also altered by the chemical. The factorsaffecting the number of nodes in each of these zones of growthare discussed, and it is suggested the sprays reduced the levelof endogenous auxins in the leaves and endogenous gibberellinsin the shoot tips. Differences associated with the vigour ofthe trees and with seasonal factors were also observed. Thedifficulties in estimating these factors limit the commercialvalue of this technique.     

胡杨枝芽生长特征及其展叶物候特征

以5个不同发育阶段的胡杨(Populus euphratica Oliv.)个体为研究对象,观测记录了枝芽展叶物候、枝芽生长特征和叶形变化的空间分布规律。结果表明:不同发育阶段的胡杨个体以及同一个体树冠的不同层次,其枝芽生长及其展叶物候期表现出不同的时空特征。随着树龄的增加和树冠层次的增高(由基向顶),当年新生枝条长度、枝条叶片数和叶形指数逐渐减小,但叶面积和叶片干重逐渐增大。5个不同发育阶段胡杨个体均表现出展叶物候始于树冠顶层,依次向下结束于树冠基部;展叶物候期共性表现在枝芽萌动期均在4月上旬,起始展叶期集中在4月中旬,展叶终期则在5月上旬到下旬;树龄较大的个体其枝芽萌动期、起始展叶期、展叶终期较树龄较小的个体早;其枝芽萌动期到展叶终期的时间进程较树龄较小的个体短;不同发育阶段的个体枝芽萌动期出现的时间较为离散,起始展叶期和展叶终期出现的时间较为集中。相关分析表明,出叶周期与枝条长度、枝条叶片数量和叶形指数呈极显著正相关,与叶面积和叶片干重呈显著负相关。     

Fruit Regulates Bud Sprouting and Vegetative Growth in Field-Grown Loquat Trees (Eriobotrya japonica Lindl.): Nutritional and Hormonal Changes

The effects of fruit on bud sprouting and vegetative growth were compared on fruiting and defruited loquat trees from fruit set onward. Carbohydrate and nitrogen content in leaves and bark tissues and hormone concentrations were studied during the fruit development and vegetative growth periods. On defruited trees, a significant proportion of buds sprouted in winter, whereas buds from fruiting trees sprouted only in the spring when fruit reached its final size. Furthermore, when panicles were completely removed in autumn, the buds also sprouted. In addition, fruit directly affected vegetative growth by reducing shoot length. An effect of sink removal (flower or fruit) promoting bud sprouting, regardless of the season, was then demonstrated. Neither soluble sugar concentration nor nitrogen fraction concentration in leaves or bark tissues was related to bud sprouting, but a certain nutritional imbalance was observed during the most active period of fruit development. Moreover, fruit sink activity significantly modified hormone content by increasing indole-3-acetic acid (IAA) and reducing zeatin concentrations, resulting in a higher IAA/zeatin ratio parallel to the lower bud sprouting intensity. Therefore, these changes caused by fruit removal are all related to vegetative growth, but there is no evidence that they are responsible for bud burst.     

Basipetal Gradient of Axillary Bud Inhibition Along a Rose (Rosa hybridaL.) Stem: Growth Potential of Primary Buds and their Two Most Basal Secondary Buds as Affected by Position and Age

InRosa hybridaL. cv. Ruidriko ‘Vivaldi’®, theeffect of position on growth and development potentials of axillarybuds was investigated by single internode cuttings excised alongthe floral stem and its bearing shoot. The experiments werecarried out in both glasshouses and in a phytotron. The studyfirstly concerned the development of the primary shoot fromthe onset of bud growth until anthesis. The primary shoot wasthen bent horizontally to promote the growth of the two mostproximal secondary buds, the collateral buds, already differentiatedinside the primary bud. They gave rise to basal shoots. In thebasipetal direction, the axillary buds along the floral stemexhibited both an increase in the lag time before bud growthand a decrease in bud growth percentage, demonstrating the existenceof a physiological basipetal gradient of inhibition intrinsicto the buds or due to short range correlations. The same basipetalgradient of inhibition was observed along the floral stem andits bearing shoot, demonstrating that the age of the bud wasnot a major factor in determining the rate of bud growth. Afterbending the primary shoot, the percentage of collateral budgrowth was also affected by the cutting position. The more proximalthe cutting, the lower the sprouting ability of collateral buds.The growth potential of these buds appeared to be already determinedinside the main bud before cutting excision.Copyright 1998 Annalsof Botany Company Axillary bud; basal shoot; cutting; development; endodormancy; growth; paradormancy; position; primary shoot;Rosa hybridaL.; rose; secondary bud; topophysis.     

Leaf flushing and shedding,bud and flower production,and stem elongation in tall birch trees subjected to increases in aboveground temperature

Key message

Tall birch trees allocate extra resource due to aboveground temperature elevation to bud and male flower production rather than to plant growth. Saplings increased only plant growth under warming. Size-dependent response should be considered.

Abstract

We experimentally heated canopy organs of tall birch trees (Betula ermanii Cham.; 18–20 m high) growing at a high latitude to determine how leaf phenology, plant growth, and bud and male flower production might shift in response to increases in aboveground temperature during global climate change. We warmed the canopies with infrared heat lamps fixed to steel pipe scaffolds built around the trees. The temperature of the warmed canopies increased by approximately 1 °C. Warming extended the length of the growing season of canopy leaves (by accelerating leaf flush and delaying leaf fall), and significantly increased the numbers of buds and male flowers per shoot. Bud production and shoot length were positively correlated in both warmed and control branches. However, warming did not increase canopy shoot lengths. The intercept value of the positive regression slope between bud production and shoot length for warmed branches was higher than that for control branches. Thus, canopy warming had a direct positive effect on the bud production but had no indirect effect via increases in shoot length. Our experiment showed that tall birch trees allocated extra resources made available by increased aboveground temperature to bud and male flower production rather than to plant growth.

     

Development of shoot inHydrangea macrophylla II. sequence and timing

The development of axillary buds, terminal buds, and the shoots extended from them was studied inHydrangea macrophylla. The upper and lower parts in a nonflower-bearing shoot are discernible; the preformed part of a shoot develops into the lower part and the neoformed part into the upper part (Zhou and Hare, 1988). These two part are formed by the different degrees of internode elongation at early and late phases during a growth season, respectively. Leaf pairs in the neoformed part of the shoot are initiated successively with a plastochron of 5–20 days after the bud burst in spring. The upper axillary buds are initiated at approximately the same intervals as those of leaf pairs, but 10–30 days later than their subtending leaves. Changes in numbers of leaf pairs and in lengths of successive axillary buds show a pattern similar to the changes in internode lengths of the shoot at the mature stage. The uppermost axillary buds of the flower-bearing shoot often begin extending into new lateral shoots when the flowering phase has ended. The secondary buds in terminal and lower axillary buds are initiated and developed in succession during the late phase of the growth season. Internode elongation seems to be important in determining the degrees of development of the axillary buds. Pattern of shoot elongation is suggested to be relatively primitive. Significances of apical dominance and environmental conditions to shoot development are discussed.     

Vegetative Architecture of Elaeocarpus hookerianus. Transition from Juvenile to Adult

Elaeocarpus hookerianus Raoul is a profoundly heteroblastictree native to New Zealand. We describe and quantify changesin leaf morphology and anatomy, and in branching pattern atdifferent levels of insertion. Discrete juvenile, adolescentand adult phases were identified. The divaricating juvenilebore small leaves with thin laminae and an anatomy typical ofshade-plants. Juveniles had dense canopies, many thin horizontaland vertical axes, wide branch angles and highly variable branchingpatterns. Adolescents had larger leaves, fewer horizontal axeson a single, leading vertical axis, and a more consistent branchingpattern. Adults were arborescent, producing the largest, mostdifferentiated leaves on the stoutest and longest horizontalbranches. Data indicate a three-phased strategy for: (a ) providingresponsive, energy-efficient shoot systems under low-light regimes;(b ) growing rapidly to the forest canopy; and (c ) exploitingfor the forest canopy environment. Elaeocarpus hookerianus Raoul; heteroblasty; leaf morphology; leaf anatomy; branching pattern     

Effects of Plant Growth Regulators and Nutrient Supply on Tiller Bud Outgrowth in Barley (Hordeum distichum L.)

Seedlings of spring barley were raised in 100 and 20% nutrientsolution and treated with a foliar application of Terpal, Cerone,TIBA, GA₃ or BAP. The growth of individual tiller buds and tillers,the main shoot and the root system was recorded over the following15 d. Terpal and Cerone stimulated tiller bud elongation within5 d at both nutrient levels and after 15 d the number of emergedtillers was increased at the higher nutrient level. Terpal characteristicallypromoted the growth of secondary tiller buds whereas Ceronepromoted the emergence of the coleoptile tiller; both thesePGRs also retarded the development of the main shoot. TIBA increasedthe number of elongating tiller buds but this did not resultin greater tillering. GA₃ reduced the number of elongating tillerbuds and restricted their growth, especially in the high nutrientregime; this was accompanied by an increase in main shoot elongation.The growth and development of tiller buds was reduced by BAPand the number of emerged tillers was reduced at 15 d in bothnutrient levels; main shoot dry weight and root elongation werealso reduced. The results are considered in relation to theoverall influence of hormonal factors and mineral supply ontiller bud outgrowth. Hordeum distichum, spring barley, tiller bud outgrowth, plant growth regulators, Terpal, Cerone, GA₃, BAP, nutrient supply, apical dominance, TIBA     

Development of Axillary and Leaf-opposed Buds in Rattan Palms

Axillary vegetative buds are present in Calamus, Ceratolobus,and Plectocomiopsis. Two species of Daemonorops Sect. Piptospathaalso have axillary vegetative buds. All species of Daemonoropshave only displaced adnate axillary inflorescence buds. A singlebud is initiated in the axil of the first or second leaf primordiumin a way similar to that for axillary inflorescence buds. Themeristem is displaced during development on to the internodeabove and sometimes on to the base of the leaf above. Leaf-opposedvegetative buds occur in five species of Daemonorops Sect. Cymbospathaand in one species of Daemonorops Sect. Piptospatha. This typeof bud is initiated 180° away from the axil of the firstor second leaf primordium. It is not a displaced axillary bud,but does become adnate to the internode above like the axillarybuds. One or more leaves, transitional between juvenile andadult, on a shoot often subtend both types of buds. Myrialepishas leaf-opposed vegetative buds, but their development wasnot observed. Korthalsia has buds that are displaced about 130°from the leaf axil and are intermediate between the axillaryand the leaf-opposed condition. Other forms of vegetative budsare described: multiple buds in Plectocomia, aerial forkingin Korthalsia, and suckering from inflorescences and from aerialstems in Calamus. bud development, rattan palms, palm taxonomy, branching     

Correlative Inhibition of Lateral Bud Growth in Pisum sativum L. and Phaseolus vulgaris L.: Studies of the Role of Abscisic Acid

The possibility has been investigated that abscisic acid (ABA)might act as a correlative inhibitor of lateral bud growth inPisum sativum and Phaseolus vulgaris. Application of ABA insmall quantities (2µg) to axillary buds on decapitatedplants of P. sativum caused appreciable inhibition of theirgrowth, and induced a compensatory growth of the bud on an adjacentnode. Application of this same quantity of ABA to axillary budson decapitated plants of Phaseolus vulgaris was without effect,but a high concentration in lanolin (1 mg g^–1) did substantiallyreduce bud outgrowth. Endogenous ABA-like substances in Phaseolusvulgaris, detected by bioassay and electron capture g.l.c.,were present in similar concentrations in shoot tips, lateralbuds on intact plants and lateral buds on plants decapitated24 h earlier. The effects of applied ABA suggested that it might be involvedin the mechanism of correlative inhibition in Pisum sativum,but it was not possible to test this hypothesis by determiningendogenous ABA levels in axillary buds because of their smallsize. The evidence presented here suggests that ABA is not acorrelative inhibitor in Phaseolus vulgaris even though at highconcentration it can inhibit the growth of axillary buds.     

Frost damage and its cascading negative effects on <Emphasis Type="Italic">Aesculus</Emphasis><Emphasis Type="Italic">glabra</Emphasis>

Frost damage and re-foliation are seldom quantified for forest species, but are of ecological and evolutionary importance. This study of Aesculus glabra (Ohio buckeye) in a deciduous forest remnant in Illinois, USA, quantified frost damage to leaves and flowers after sub-freezing temperatures in April 2007. It also documented re-foliation and later growth, reproduction, and survival in 2007–2009 for the 355 study individuals of four life stages growing 0–200 m from the forest edge. Life stages differed in % leaf damage because of differences in phenology during the frost. Large saplings with fully expanded, immature leaves had higher % damage and lower % canopy fullness after re-foliation than smaller saplings with partially or fully mature leaves and canopy trees undergoing shoot expansion with folded leaflets. Percent damage increased for saplings closer to edges. Large saplings with heavier frost damage to leaves had partial re-foliation in deep shade, lower % canopy fullness, earlier senescence, a shorter growing season, and greater death of next year’s buds. By 2008, large saplings with greater damage in 2007 had more dead branches and lower % canopy fullness. By 2009, 11% of large saplings had died. In 2007, frost damaged no flowers, but final fruit crop size was negatively related to % leaf damage. Edge trees with total leaf damage aborted all fruits. The frost event differentially affected individuals in their length and time of growing season, energy budget, and, ultimately, reproduction, and survival. The population’s local-scale demography and spatial pattern also changed as large saplings died.