The Genesis of Form in Casuarinaceae

The growth and development of the shoot apex of Casuarina distyla, in which the leaves commonly occur in whorls of 6-8 members, is described. The mature apex of C. torulosa, a species with only four leaves per whorl, is also described. Stages in the development of the apex of C. distyla are illustrated with three-dimensional scale drawings. The fused stem-and-leaf nature of the vegetative axis is recognized and the growth of the blade, tube and buttress portions of the axes is presented in units of length and volume. Stages in the development of axillary buds are illustrated with three-dimensional scale drawings. Phyllotactic parameters for whorled systems of phyllotaxis in Nerium and Casuarina are presented along with those for decussate systems in Eucalyptus. The role of physical constraint in the genesis of form and the determination of rates of growth in shoot apices are discussed and it is suggested that rapid maturation of tissues may contribute to the continuous fall in the relative growth rate of the leaves.

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Effect of Photoperiod on Growth and Development of Cassava (Manihot esculenta Crantz)

Functional Plant Biology ◽

10.1071/pp9850621 ◽

1985 ◽

Vol 12 (6) ◽

pp. 621 ◽

Cited By ~ 6

Author(s):

BA Keating ◽

GL Wilson ◽

JP Evenson

Keyword(s):

Growth Rate ◽

Relative Growth Rate ◽

Growth And Development ◽

Day Treatment ◽

Storage Root ◽

Storage Roots ◽

Manihot Esculenta Crantz ◽

Dry Matter Partitioning ◽

Relative Growth ◽

Controlled Environments

Effects of photoperiod on growth and development of cassava were studied in controlled environments. Plants of cultivars M Aus 7 and M Aus 10 were grown under short (10-h) and long (16-h) photoperiods and harvested at approximately weekly intervals for a period of 13 weeks. Long photoperiods resulted in large increases in leaf area through increases in both number (both cultivars) and size of leaves (M Aus 7 only). The timing, extent and anatomical characteristics of storage root initiation were similar for both cultivars under 10-h and 16-h photoperiods but the subsequent balance between shoot and storage root growth strongly favoured shoot growth in long days. Dry matter partitioning followed a simple allometric pattern with the proportionality between the relative growth rate of shoots and the relative growth rate of storage roots remaining constant with time but being altered by photoperiod. Distribution to storage roots was quantitatively reduced in another experiment using M Aus 10 with each additional 1-h increment from 10-h to 16-h photoperiods. A treatment consisting of a short day (10 h) plus a 1-h night break in the middle of the dark period produced growth similar to long day treatment. Differences in cultivar response (Ceiba, CMC 84 and M Aus 7) to a range of photoperiods (11, 12, 13 and 14 h) were detected in a third experiment. The possible mechanisms and significance of these responses are discussed.

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The effect of photoperiod on the growth and development of Echinochloa spp. Millets

Australian Journal of Experimental Agriculture ◽

10.1071/ea9850428 ◽

1985 ◽

Vol 25 (2) ◽

pp. 428 ◽

Cited By ~ 2

Author(s):

DK Muldoon

Keyword(s):

Growth Rate ◽

Relative Growth Rate ◽

Growth And Development ◽

Apical Meristem ◽

Leaf Number ◽

Relative Growth ◽

Short Day ◽

Crop Development ◽

Abnormal Head ◽

Main Tiller

Two cultivars of Echinochloa utilis, Ohwi et Yabuno, and one E.frumentacea (Roxb.) Link cultivar were grown in a glasshouse under three photoperiod regimes: naturally varying photoperiods (1 2-1 3 h), and fixed photoperiods of 14 and 16 h. Both species behaved as quantitative short-day plants although, in E. utilis, extending the photoperiod from 14 to 16 h delayed head emergence disproportionately. The delay in head emergence did not affect the relative growth rate, and longer photoperiods led to higher shoot weights; main tiller leaf number increased only slightly. The commencement of apical meristem elevation was delayed under longer photoperiods, a feature believed to be beneficial to regrowth. A time-of-sowing study in the field illustrated the effect of this short-day response upon crop development. Sixteen introduced E. utilis cultivars and 10 E. frumentacea cultivars also behaved as quantitative short-day plants. Within each species there were differences between cultivars in sensitivity to photoperiod. Some cultivars of E. utilis were very late and had abnormal head emergence at 16 h. Latitudinal effects on the performance of these cultivars are discussed.

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Growth and development of shoot apex in barley II. Distribution of growth rates during vegetative phase

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.1980.003 ◽

2014 ◽

Vol 49 (1-2) ◽

pp. 33-48 ◽

Cited By ~ 1

Author(s):

Zygmunt Hejnowicz ◽

Wiesław Włoch

Keyword(s):

Growth Rate ◽

Shoot Apex ◽

Growth And Development ◽

Distal Part ◽

Relative Rate ◽

Volume Growth ◽

Leaf Primordia ◽

Relative Growth ◽

Apical Dome ◽

The Mean

The changes in the volume of the apical dome and of the frusta indicate that the mean relative rate of volume growth of the whole apical dome is much higher than in the first frustum which, in turn, grows much faster than the next one. It was found in studies of the distribution of mitoses and of cell arrangement that the volume relative growth rate of the distal part of the apical dome is at least 5-10 times slower than that at the level of new leaf primordia initiation.

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The physiology of growth in Subterranean clover. I. Seedling growth and the pattern of growth at the shoot apex

Australian Journal of Botany ◽

10.1071/bt9700127 ◽

1970 ◽

Vol 18 (2) ◽

pp. 127 ◽

Cited By ~ 6

Author(s):

RF Williams ◽

D Bouma

Keyword(s):

Growth Rate ◽

Relative Growth Rate ◽

Shoot Apex ◽

Exponential Growth ◽

Leaf Growth ◽

General Pattern ◽

Subterranean Clover ◽

Growth Period ◽

Vascular Differentiation ◽

Relative Growth

The shoot apex of Trifolium subterraneum L. is spirodistichous, with a divergence angle of 160° and a phyllotaxis index of 2. The vegetative plant is defined quantitatively in terms of lengths of successive leaves, leaf areas, and dry weights of the leaves and all major plant parts for a 29-day growth period. The selected environment gave very high values of net assimilation rate (3 .0 mg cm-2 day-1for early growth). The properties of the shoot apical system are further defined in terms of volumes of meristematic and very young parts. The picture is extended by linking it with fresh weight data for the leaves. To a remarkable extent the data, transformed to logarithms, can be accounted for by arrays of linear regressions on time, the members of which show decreasing slopes with increasing leaf number. However, the most instructive description is obtained from an array of relative growth rate curves for successive leaves. While the existence of one general pattern of leaf growth seems unlikely, there is evidence for a marked increase in relative growth rate during leaf initiation. Exponential growth in length seems to be fairly common in young leaf primordia, but exponential growth in volume occurs in a variety of patterns in different plants. Attempts to link these occurrences with events in vascular differentiation and thus with the supply of substrate for growth have not been successful. It is suggested that properties of the system as a whole may be relevant.

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