Effect of Potato Seed-Tuber Age on Plant Establishment and Amelioration of Age-Linked Effects with Auxin

Abstract

Studies were conducted to characterize the effect of advanced potato (Solanum tuberosum L.) seed-tuber age on plant growth potential and whole-plant morphology. Plant growth from singleeye seedcores from 5-to 18-month old 'Russet Burbank' seedtubers was compared. Loss in apical dominance was apparent with advanced age. On a per-core basis, the amount of plant dry weight was equal for the two ages at 30 days from planting. However, individual plants from older cores displayed reduced shoot, root and leaf dry weights, leaf area, and leaf number. These effects reflected altered dry-matter partitioning and contributed to an overall change in plant morphology with advanced age. On a total seedcore basis, relative growth rate of plants from older seedcores was greater than that from younger seedcores over the 30 day growth interval. Leaf area ratio was also greater for plants from the older seedcores; however, unit leaf rate was not affected by tuber age and plants from both young and old seedcores assimilated dry matter at the same rate. Age-induced differences in growth indices reflected differences in the degree of plant differentiation over the interval of study. Treating younger seedcores with 1-naphthaleneacetic acid (NAA) prior to planting inhibited overall plant growth. In older cores, NAA stimulated root growth, restored apical dominance, decreased leaf number per plant, and increased average leaf area per leaf. In short, NAA altered the morphology of plants growing from older seedcores to more closely resemble that of plants growing from younger seedcores. While auxin significantly altered plant form, vigor of plants from older seedcores was not fully restored by auxin treatment, indicating that age-reduced vigor of potato seed-tubers is not solely mediated by auxin.Early sprout vigor significantly influences yielding ability of potato (Solanum tuberosum L.) (17). Seed-tuber physiological age, a somewhat subjective measure ofthe developmental status of a tuber, is a major factor in determining the number and vigor of shoots produced upon sprouting. Indeed, seedtuber age influences all stages of daughter plant growth, from sprouting to final yield (2,3,6,7 (10,11). The length of the incubation phase is temperature dependent, with low temperatures prolonging it and higher temperatures accelerating it (5). Hence, a given physiological age can be produced by manipulating storage temperature and/or length of the storage period.Many of the age-induced alterations in potato plant growth appear to be auxin related. For example, treatment of 20-month-old potato seed-tubers with auxin decreased the number of stems produced per seedpiece and increased the average tuber size and total yield (9). With advancing age, the loss in apical dominance is first evident between eyes on the tuber, and eventually multiple sprouts are produced within each eye. Auxin may play a key role in the regulation of apical dominance in many plants (18). Thus, sprouts developing from aged seed-tubers may have a reduced ability to synth...

Oxidative metabolism and the physiological age of seed potatoes are affected by increased α‐linolenate content

“…2 illustrate, on an individual plant (per stem) basis, the relative effects of seed-tuber age and unsaturation level on the dry matter partitioning and overall morphology of 24-day-old plants from 4and 16-month-old seed-tubers. Consistent with previous results for Russet Burbank tubers (Mikitzel and Knowles 1990), older Desiree (WT) tubers produced twice as many mainstems (P Յ 0.01) and thus plants per tuber as younger tubers. Equivalent increases in total plant DW from the older tubers were not evident.…”

“…This was particularly evident for the FAD 3+7 tubers in which α‐linolenate levels were the highest. Increased stem number and lower plant DWs are characteristics of physiologically older tubers of this chronological age (Mikitzel and Knowles 1990, Kumar and Knowles 1993a). Hence, the increased unsaturated fatty acid content of FAD 3+7 tubers accelerated ageing over the 16‐month storage interval to effect a reduction in plant growth potential relative to WT tubers.…”

Changes in Lipid Peroxidation and Lipolytic and Free-Radical Scavenging Enzyme Activities during Aging and Sprouting of Potato (Solanum tuberosum) Seed-Tubers

“…The potato (Solanum tubevosum L.), being vegetatively propagated by seed-tuber cuttings, provides such a system. Russet Burbank potato seed-tubers remain viable for approximately 3 years from harvest (at 4OC, 95% RH); however, the process of aging from about 7 through 24 months results in a gradual loss of sprout vigor (Mikitzel and Knowles, 1990;Kumar and Knowles, 1993). Further aging (through 36 months) leads to complete loss of sprouting ability, and the axillary meristems within each node of the tuber precociously form small tubers (Krijthe, 1962;Kumar and Knowles, 1993).…”

The sweetpotato ADP-glucose pyrophosphorylase gene (ibAGP1) promoter confers high-level expression of the GUS reporter gene in the potato tuber

“…The sucrose-inducibility of the ibAGP1 promoter may be an additional benefit since transgenic potato can be easily propagated in an in vitro system [57,58], and mini-tubers can be easily induced in a controlled system [59][60][61]. Indeed, results from earlier studies suggest that in vitro tuberization does not require any other growth regulators but, rather, relies on the presence of a high sucrose concentration in the culture media [62].…”