Larry D. Noodén

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• PhD
• Professor Emeritus at University of Michigan

Senescence is an internally programmed degenerative process leading to death of an organism, organ or cell. A practical and immediate upshot of the complications and uncertainties described above is the problem of what parameter(s) to use as a measure of senescence. During the reproductive phase, the roots of a soybean plant slow their growth and m...

Having clear concepts of senescence and aging, as well as the diverse related terminology, will foster these and related fields by facilitating communication within and between the academic constituencies that study them. Moreover, it will enable those working on photosynthetic tissues to contribute more to and draw more help from other fields rang...

Senescence in plants is usually viewed as an internally programmed degeneration leading to death. It is a developmental process that occurs in many different tissues and serves different purposes. Generally, apoptosis refers to programmed death of small numbers of animal cells, and it shows some special features at the cell level. Some senescing pl...

For most monocarpic species studied, blocking fruit development prevents or at least delays the death of the plants. However, it usually does not prevent the decline in photosynthetic rate, while it may or may not maintain the photosynthetic components (machinery) such as chlorophyll and ribulose 1,5-bisphosphate carboxylase. Since sink demand infl...

Daring monocarpic senescence in potted soybeans (Glycine maxi(L.) Merrill cv. Anoka) grown in controlled-environment chambers, foliar chlorophyll, soluble protein nitrogen, total nitrogen, and starch decline (roughly in that order). All of these precede visible yellowing and, of course, abscission. The pattern of yellowing within a leaf is not unif...

The sinking and floating (density) of the special winter buds (turions) produced by many aquatic plants play important roles in their life cycles, yet there has been little experimental study of these phenomena. However, it has been postulated that starch determines the density of turions. In order to test this hypothesis, turions of Myriophyllum v...

This chapter discusses causes of monocarpic senescence and senescence in polycarpic plants and clones. Whole plant senescence is viewed primarily in terms of leaf senescence and it is measured mainly through chloroplastic parameters such as chlorophyll loss and decreased photosynthesis. In monocarpic plants where senescence and death closely follow...

This chapter reviews the genes that alter senescence. Many of the genes that alter senescence appear to be involved in other biological processes and are not solely devoted to senescence, so it is difficult to distinguish indirect and direct effects of genes on senescence. Genes that alter senescence exert both positive and negative regulatory effe...

This chapter focuses on the light control of leaf senescence. Light control of leaf senescence reflects important environmental controls of plant development and has many practical applications as well. Light is required for the photosynthesis that sustains plant growth and long-term survival and also has many practical applications. The postharves...

Programmed cell death is a common pattern of growth and development in both animals and plants. However, programmed cell death and related processes are not as generally recognized as central to plant growth. This is changing fast and is becoming more of a focus of intensive research. This edited work will bring under one cover recent reviews of pr...

The 'stay-green' mutation cytG in soybean (Glycine max) partially inhibits the degradation of the light-harvesting complex II (LHCII) and the associated chlorophyll during monocarpic senescence. cytG did not alter the breakdown of the cytochrome b6/f complex, thylakoid ATP synthase or components of Photosystem I. In contrast, cytG accelerated the l...

Like most monocarpic plants, longevity of Arabidopsis thaliana plants is controlled by the reproductive structures; however, they appear to work differently from most dicots studied. Neither male- and female-sterility mutations (ms1-1 and bell1, respectively) nor surgical removal of the stems with inflorescences (bolts) at various stages significan...

During leaf senescence, chioroplast proteins, lipids and pigments undergo massive degradation releasing large amounts of nutrients for reuse elsewhere. Understandably, the chloroplast-degrading machinery has been considered to operate within the chloroplast itself. However, most of those lipases and proteases that increase during senescence and hav...

Whether or not low frequency electromagnetic fields can affect living systems is an important biological question with public health implications. Smith et al. [1] reported that the growth of seedling of Raphans sativus L., the common garden radish, was enhanced when exposed for 21 days in a continuous 60 Hz electromagnetic field tuned to the ‘ion...

Some ferns growing in areas with severe winters maintain green leaves through the winter; however, very little is known about the physiology of their remarkably hardy leaves, and the function of the wintergreen trait has not been completely established. Both Polystichum acrostichoides and Dryopteris intermedia retain high concentrations of chloroph...

Given the influence of photoperiod on reproductive development and whole-plant senescence in monocarpic plants, one would suspect that leaf senescence in these plants might be under photoperiodic control. In Arabidopsis thaliana, which is monocarpic and also a nonobligate long-day (LD) plant, LDs (16 h, 300 μmol m−2 s−1) caused leaves to die earlie...

The stay-green mutations cytG and Gd1d2 prevent the normal yellowing during senescence of soybean (Glycine max) leaves and cotyledons. Because light plays such an important role in regulating morphogenesis and it promotes the formation of chlorophyll (Chl), we determined the effect of cytG and Gd1d2 (in a cv. Clark background) on the development an...

Substantial evidence has indicated that cytokinins (CKs) inhibit senescence of a variety of plant organs, especially leaves, but how, or even whether, CK operates as an antisenescence signal in the intact plant needed to be determined. Because soybean has a number of advantageous features, we chose to analyse CK regulation of leaf senescence in tha...

On the way from the roots to the seeds during reproductive development in soybean (Glycine max), a large proportion of the minerals pass through the leaves rather than travelling directly via the xylem. This direct and indirect movement of mineral nutrients has important implications for mineral redistribution, seed development and leaf senescence....

Soybean plants (Glycine max [L.] Merr. cv Clark) carrying nuclear and cytoplasmic "stay-green" mutations, which affect senescence, were examined. Normally, the levels of chlorophyll (Chl) a and b decline during seedfill and the Chl a/b ratio decreases during late pod development in cv Clark. Plants homozygous for both the d(1) and d(2) recessive al...

Defined solutions containing cytokinin and/or mineral nutrients were supplied in lieu of the roots through the cut stem base of soybean explants (a leaf with associated pod and subtending stem segment) in order to analyze the roles of cytokinin and mineral nutrients from the roots in pod development and foliar maintenance. In explants cut at early-...

Cytokinins (CKs) coming from the roots via the xylem are known to delay leaf senescence, and their decline may be important in the senescence of soybean (Glycine max) plants during pod development (monocarpic senescence). Therefore, using radioimmunoassay of highly purified CKs, we quantified the zeatin (Z), zeatin riboside (ZR), the dihydro deriva...

Several genes can alter the yellowing processes that normally occur during pod development and monocarpic senescence in soybean. CytG and d 1 + d 2 cause the leaves and seeds to stay green at maturity. G blocks yellowing of the seed coat but not the leaves or embryos. By contrast, another gene, y 3 , causes earlier yellowing of the leaves. This pap...

This chapter discusses causes of monocarpic senescence and senescence in polycarpic plants and clones. Whole plant senescence is viewed primarily in terms of leaf senescence and it is measured mainly through chloroplastic parameters such as chlorophyll loss and decreased photosynthesis. In monocarpic plants where senescence and death closely follow...

When [(3)H]dihydrozeatin riboside and [(3)H]zeatin riboside were supplied to soybean (Glycine max L.) explants (comprising one leaf, associated pods, and subtending stem) via the xylem at mid to late podfill, 0.1% of the supplied (3)H was extracted from the seeds. The distribution of (3)H in the explants was similar to that bound previously followi...

Evidence from earlier studies with explants (stem cutting with a leaf and a pod) indicates that a decline in the supply of mineral nutrients from the roots may prepare the leaves for induction of monocarpic senescence in soybean [Glycine max (L.) Merrill cv. Anoka). In order to assess the changes in mineral flux from the root system, xylem sap was...

Uptake of the dinitroaniline herbicide oryzalin (3,5-dinitro-N4, N4-dipropylsulfamlamide) and its effect on root growth were studied using 5 mm corn (Zea mays L.) and pea (Pisum sativum) root apices. Pea root growth was much less susceptible to oryzalin than corn root growth. Uptake studies showed that pea root apices also accumulated much less [14...

The metabolism of [(3)H]6-benzylamino purine was studied in presenescent and early senescent soybean (Glycine max [L.] Merr.) leaves. In both types of leaves, the metabolism was essentially the same. The principal metabolite was identified as beta-(6-benzylaminopurin-9-yl)alanine by mass spectral studies, which included discharge ionization-seconda...

Normally, starch (sugars) and minerals are redistributed from the leaves to the pods during monocarpic senescence in maturing soybean plants. Petiole phloem destruction (steam girdling), which blocked this redistribution by interrupting export through the petiole, altered the foliar senescence pattern producing a distinctive interveinal yellowing w...

Normally, starch (sugars) and minerals are redistributed from the leaves to the pods during monocarpic senescence in maturing soybean plants. Petiole phloem destruction (steam girdling), which blocked this redistribution by interrupting export through the petiole, altered the foliar senescence pattern producing a distinctive interveinal yellowing w...

Senescence is an internally controlled degeneration leading to death [4]. From the cell level to the whole plant level, most processes decline; however, this loss of vital functions and disassembly of the cell’s internal structure is a highly ordered process [17, 19]. Indeed, senescence serves a variety of important functions in plant development [...

Although the seed coat, through its thickness and permeability, often regulates seed germination, very little is known about the control of its development. Using soybean (Glycine max [L.] Merrill) explants, podbearing cuttings in which defined solutions can be substituted for the roots, we have demonstrated that cytokinin and mineral nutrients mov...

Because triiodobenzoic acid increases pod number, albeit variably, in soybean (Glycine max), we tested other auxin-transport inhibitors. Morphactins, especially methylchlorflurenol (MCF), were found to be very active (optimal concentration 10 micromolar) when sprayed onto the foliage. Applications at 1 week after the start of flowering were most ef...

Translocation of 14C-labeled assimilates from soybean leaves to the pods was examined during pod maturation and leaf senescence. The degree of seed development was expressed as stages of radicle yellowing which was related to other changes in the seeds as well as yellowing of the carpels, the leaf veins and the leaf intervenal tissue. To study tran...

Soybean explants (leaf, pod and subtending stem segment) excised at early-mid podfill and cultured on a mineral nutrient solution senesce much sooner than comparable intact structures. Pod development is also advanced, but seed yield is reduced. Cytokinin added to the mineral nutrient medium retards leaf yellowing, blade abscission, petiole absciss...

We investigated the degree to which developing fruit compete directly with leaves for mineral nutrients, e.g. phosphate coming up from the roots. When soybean (Glycine max (L.) Merrill cv. Anoka) explants cut at mid-late podfill were given a 15-min pulse of 32Pi via the cut stem and then transferred to distilled water, 75% of the 32P accumulated in...

Over two millenia, observers of plants have noticed that one part of a plant may influence or control the activities of another part (see, e.g., Wiesner 1871, Dostal 1967). There are diverse examples, such as axillary buds growing out when the main bud has been removed (Goebel 1900, Snow 1925), excision of seeds from fleshy fruit promoting their ge...

The leaves of intact soybean plants (Glycine max. L. Merrill) characteristically turn yellow and abscise during pod maturation, and this may limit seed growth. We have used soybean expiants (excised 10 cm stem sections with a leaf and midfill pod attached) to study interactive effects of nutrient and hormone supply on leaf senescence symptoms and s...

Soybean explants consisting of a leaf, one or more young pods, and a subtending piece of stem were given a 1-h pulse of 3 H (ring-labeled)-zeatin riboside (ZR) or -zeatin (Z), via the base of the stem, followed by a 24-h incubation. At the end of the pulse, about 55% of the soluble 3 H was in the leaf blades, 11% in the petiole, 30% in the stem, 2%...

Excised soybean (Glycine max [L.] Merrill) cv Anoka leaf discs tend to remain green even after the corresponding intact leaves have turned yello on fruiting plants. We have found that explants which include a leaf along with a stem segment (below the node) and one or more pods (maintained on distilled H(2)O) show similar but accelerated leaf yellow...

During monocarpic senescence in soybean (Glycine max [L.] Merrill cv. Anoka) there is a remobilization of nitrogen from the leaves to the seeds, and it has been hypothesized that this loss of nitrogen from the leaves induces foliar yellowing. The phloem in a small segment of the petiole between the pods and the target leaf can be inactivated with a...

The patterns of abscisic acid circulation between the leaves and the pods change during pod development and monocarpic senescence in soybeans.14C-ABA injected into the seed cavity of the most advanced pod moves to less advanced pods and mostly to pods at the same node, but very little travels to the leaves.More of the injected ABA is translocated d...

The intracellular binding of dinitroaniline herbicides was studied in order to analyze the mechanism of their colchicine-like action. When corn root apices (5 millimeters) are incubated in [(14)C]oryzalin (a dinitroaniline herbicide), the (14)C is taken up rapidly, reaching a plateau in about 4 hours, which corresponds to the minimum incubation tim...

Foliar applications of α-naphthaleneacetic acid, together with 6-benzyladenine, prevent the seed-induced degeneration (monocarpic senescence) in soybeans. In addition to halting leaf yellowing and shedding, this treatment prevents the loss of starch and nitrogen that occurs during senescence of these leaves. Although nitrogen and starch are normall...

The involvement of cytokinins and abscisic acid (ABA) in the monocarpic senescence (foliar yellowing following fruit development) of soybeans was examined. Foliar sprays of cytokinin (10-4 M zeatin or 10-5 M benzyladenine), begun when the plants first set fruit and repeated every other day, significantly delayed, but did not prevent, monocarpic sen...

The interaction between histone and nonhistone chromatin proteins has been investigated by histone affinity chromatography, a technique that avoids precipitation of histone · nonhistone complexes. When nonhistone proteins labeled with 32P are loaded directly on histone-Sepharose columns, no binding of radioactivity to the column is observed. Howeve...

This chapter describes the methods for fractionation of nonhistone proteins by histone-affinity chromatography. DNA, histones, and nonhistone proteins interact with each other in generating the structural and functional properties of chromatin. The interaction of nonhistones with histones, have the tendency to aggregate and form precipitates when m...

In corn seedling roots, colchicine and the dinitroaniline herbicide oryzalin cause swelling and inhibition of elongation which seem to be interconnected responses, yet they can be separated. First, both colchicine (10−3 M) and oryzalin (10−6 M) affect elongation (2–4 hr) well before swelling (8–10 hr). Second, a short (4 hr) oryzalin treatment prod...

The changes in distribution of several important mineral nutrients (N, K, Ca, Mg, Mn, and Fe) were studied in relation to monocarpic senescence (measured as leaf yellowing) and fruit development in hydroponically-grown (and to a lesser extent field-grown) Anoka soybeans with particular emphasis on the leaves and seeds. Only N shows a clear redistri...

MONOCARPY, a single flowering phase followed by senescence and death, is a widespread phenomenon in seed plants, particularly field crops, whose large monocultures put on a dramatic display during their senescence phase 1-4. In many, but apparently not all monocarpic species, defruiting or deflowering ,can prevent or at least delay monocarpic senes...

Colchicine and a variety of dinitroaniline herbicides (DNHs) produce a similar pattern of inhibition of elongation, induction of swelling in the elongation zone, depolarization of cell enlargement, and induction of multiple nuclei in corn seedling roots. However, a 1000-fold higher concentration of colchicine is needed to produce effects quantitati...

Soybean, a monocarpic plant, has been found to undergo rapid senescence as its fruits mature. In soybeans (Glycine max[L.] Merrill) cv. Anoka, foliar senescence begins during the period of most rapid pod-fill (seed growth), and it can be eliminated by surgical removal of the seeds at an early stage of their growth. Experiments in which fruits are r...

In order to study the relationship between fruit development and monocarpic senescence in soybeans (Glycine max. [L.] Merrill `Anoka'), rapid, nondestructive methods were developed for measuring these processes. Both senescence (leaf chlorosis) and fruit development stages are given numerical designations and described quantitatively. Senescence is...

The turions of Myriophyllum verticillatum , an aquatic vascular plant, develop in the fall and function in propagation and dispersal as well as in over-wintering. Experiments with controlled evnironments indicate that both temperature and photoperiod regulate turion formation. Turions can be induced at 15°C or lower, but not at 20°C. At 15°C, turio...

Germination, or outgrowth, of Myriophyllum verticillatum turions involves a series of visible changes starting with reflexing of leaves followed by extension and curving of the axis, and then by root formation. Before abscission, turions grow out in response to long days (16 hr) but not short days (8 hr). After abscission, turions show maximal dorm...

Axenic crown gall tumor callus (from Vinca rosea L.) which is known to synthesize its own auxin is able to convert exogenous 14C-indole or tryptamine to indoleacetic acid [5.4 and 10 × 10−6μmol × h−1× (g fr wt)−1 respectively], but little or no 3H-tryptophan is converted [less than 6.4 × 10−8×μmol × h−1× (g fr wt)−1].

An insoluble (particulate) 3H-IAA-binding system similar to that reported by Hertel et al. ( 3 ) is described in buds from pea seedlings. The binding is competed by NAA as well as IAA. Auxin-competible binding is optimal at 25�C and pH6.5; Ca+2 increases binding as does a 1 hr preincubation at 4�C. Release of apical dominance produces outgrowth and...

Dinoflagellate chromosomal proteins were analyzed by acrylamide gel electrophoresis. The electrophoretic pattern of acid-insoluble chromosomal proteins from Gyrodinium cohnii in sodium dodecylsulfate gels is less heterogeneous than that of corn, and is characterized by a paucity of bands representing molecular weights below 43 000. Acrylamide gel e...

Chromatin was prepared by two different methods from isolated nuclei of Gyrodinium cohnii (Cryptothecodinium cohnii) and Peridinium trochoideum. These isolation procedures are different from those generally used to prepare eukaryote chromatin, because the latter do not work for dinoflagellate chromatin. The chemical composition of this chromatin is...

SYNOPSIS Nuclei were isolated from Peridinium cinctum. Peridinium trochoideum, Gyrodinium cohnii ( Cryptothecodinium cohnii ) and Gymnodinium nelsoni. The nuclei of G. cohnii, P. trochoideum and G. nelsoni were found to contain ∼ 6.9, 34 and 143 picograms of DNA respectively. The ratios to DNA of RNA, acid‐soluble and acid‐insoluble protein for G....

Chromatin was prepared by 2 methods from isolated nuclei of the epicotyl, mesocotyl, and root of 4- to 5-day old maize seedlings. Extraction of the nuclei with Tris-EDTA followed by the precipitation of chromatin with 10 mM CaCl2 isolates approximately 80% of the DNA present in these nuclei. Similarly, the extraction of nuclei with 2 M NaCl isolate...

Chromatin was prepared by 2 methods from isolated nuclei of the epicotyl, mesocotyl, and root of 4- to 5-day old maize seedlings. Extraction of the nuclei with Tris-EDTA followed by the precipitation of chromatin with 10 mM CaCl 2 isolates approximately 80% of the DNA present in these nuclei. Similarly, the extraction of nuclei with 2 M NaCl isolat...

We describe a mild method for the separation and fractionation of nonhistone chromosomal proteins (NHC proteins) on a preparative scale. Rat liver chromatin is dissociated in 3 M NaCl-10 mM Tris-HCl (pH 8), and is resolved into DNA and protein by gel filtration on Bio-Gel A-50m. The resulting mixture of chromosomal proteins is concentrated by ammon...

Maleic hydrazide (MH), which causes chromosome breakage, inhibition of cell division and retardation of plant growth, inhibits nucleic acid synthesis in corn and pea seedling roots. DNA synthesis in corn roots is affected sooner than RNA synthesis; the lag times for inhibition are 4 hr and 8-12 hr respectively. MH inhibits nucleic acid synthesis in...

Chromatin has been prepared from nuclei isolated from the dinoflagellate alga Gyrodinium cohnii. This chromatin contains RNA, acid-insoluble proteins, and acid-soluble proteins; the respective ratios to amount of DNA are about 0.09, 0.48, 0.08 (by weight). Not only is the amount of acid-soluble protein associated with the DNA much less than it is i...

Colchicine has been a very useful diagnostic tool to determine if a particular developmental process requires cell division or microtubules; however, it produces certain side effects which may limit its usefulness. Low concentrations depolarize cell enlargement and higher concentrations actually inhibit cell enlargement; the threshold concentration...

IAA (indoleacetic acid) is known to induce cell enlargement without cell division in tobacco pith explants grown on an agar medium without added cytokinin. The very long lag period before IAA (2 × 10−5M) stimulates growth, about 3 days, can be useful to study the metabolic changes which lead to the promotion of growth. When the disks are transferre...

Maleic hydrazide (MH) is taken up by corn and pea seedling roots and bound to some material which is insoluble in 80% ethanol or 5% trichloroacetic acid. (14)C-MH is stable metabolically; chromatography of the 80% ethanol-soluble (14)C from treated corn roots and tobacco pith gives no indication of degradation. Very little (14)C-MH is bound in the...

Cytokinins (CKs)comingfromtherootsviathexylemare knowntodelay leaf senescence, andtheir decline maybeimpor- tantinthesenescence ofsoybean (Glycine max)plants during poddevelopment (monocarpic senescence). Therefore, using radioimmunoassay ofhighly purified CKs,wequantified thezea- tin(Z), zeatin riboside (ZR), thedihydro derivatives (DZ,DZR), the0-...

Soybeanplants (Glycine max (L.) Merr. cvClark) carrying nuclear andcytoplasmic "stay-green" mutations, whichaffect senescence, wereexamined. Normally, thelevels ofchlorophyll (ChI) aandbdecline during seedfill andtheChia/bratio de- creases during late poddevelopment incvClark. Plants homo- zygousforboththediandd2recessive alleles, attwodifferent nu...

Maleic hydrazide (MH) is taken up by corn and pea seedling roots and bound to some material which is insoluble in 80% ethanol or 5% trichloroacetic acid. 14C-MH is stable metabolically; chromatography of the 80% ethanol-soluble 14C from treated corn roots and tobacco pith gives no indication of degradation. Very little 14C-MH is bound in the zone o...

Depodding at full pod extension (prepodfill) prevents the rapid leaf yellowing and death of the soybean plant, whereas pod removal in late podfill does not. Xylem sap was collected from rootstocks under pressure over 50 min, and after purification, the sap CKS were measured by radioimmunoassay. The major CKs (DZR, ZR, DZ and Z) drop from 229 nM to...

Maleic hydrazide (MH) inhibits corn root elongation through an effect on cell division apparently without inhibiting cell enlargement. The decrease in the rate of elongation was apparent only after a considerable lag, over 14 hours, even with a concentration as high as 5 mM. MH (1 mM) did not inhibit His growth of roots from corn seeds given very l...

Selective inhibitors were used to study the connection between nucleic acid synthesis and indoleacetic acid (IAA) induction of cell enlargement. Actinomycin D (act D) and azaguanine (azaG) almost completely inhibit IAA-induced growth in aged artichoke tuber disks when they are added simultaneously with IAA. In contrast, when they are added 24 hours...

Further studies with inhibitors of protein synthesis are presented to support the conclusion, drawn from work with chloramphenicol, that protein synthesis is a critical limiting factor in auxin-induced cell expansion. The indoleacetic acid-induced elongation of oat coleoptile sections was strongly inhibited by dl-p-fluorophenylalanine, and the inhi...