Ribonuclease Activity in Tomato Leaves as Related to Development and Senescence

McHale, Janiece S.; Dove, Lewis D.

doi:10.1111/j.1469-8137.1968.tb05479.x

Cited by 33 publications

(13 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Leaves were fully turgid by the next morning. This procedure was similar to that used by Osborne (1962) and the same as used by McHale and Dove (1968b). Leaflets were then detached from the leaves and treated by 10.00 hours on Day i after detachment.…”

Section: Leaf Detachment and Phytokinin Treatmentmentioning

confidence: 99%

“…Leaf greenness was determined by reflectance using an intergrating sphere spectrophotometer set at 565 mfj. after McHale and Dove (1968b). The greener (darker) the leaf the less the reflectance.…”

Section: Sampling For Ribonuclease Activity and Greennessmentioning

confidence: 99%

“…Reflectance in units reflected at 565 m^. The greener (darker) the leaf the less the reflectance (after McHale and Dove, 1968b). fNot significant at 95% confidence level; probability of difference 60%.…”

Section: Detached Leaves-effect Of N6-benzyladenine and Kinetin On Lmentioning

confidence: 99%

“…Response to leaf detachment varies with the age of attached tomato leaves (McHale and Dove, 1968b). Ribonuclease (RNase) activity is a sensitive indicator of senescence in this system and, therefore, was used in the present study.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Age‐governed Responses of Detached Tomato Leaves to Phytokinins

McHale

Dove

1969

New Phytologist

Self Cite

View full text Add to dashboard Cite

Summary Young tomato leaves differed from older leaves in their response to phytokinin treatment after leaf detachment. N,6‐benzyladenine kept old leaves at a ribonuclease (RNase) activity level similar to that of freshly harvested material while controls increased in RNase activity. RNase activity of younger leaves was not suppressed until after a longer period of detachment but the initial post‐harvest treatment induced this effect. Young leaves treated with kinetin at first had a higher RNase activity level than controls but RNase activity in controls had increased by 8 days after detachment while activity in kinetin‐treated tissue remained near the level observed 4 days after detachment. Early response in young leaves to phytokinins was interpreted as slightly toxic, reminiscent of the more toxic response of attached leaves to phytokinins. Loss of greenness was delayed by phytokinin in both young and old leaves but RNase activity was affected first. Young leaves detached from water‐stressed plants showed an early response to N,6‐benzyl‐adenine which was similar to that obtained from older leaves after detachment. Water‐stress altered an age‐governed response to phytokinin. Phytokinins probably did not directly inhibit RNase activity, increase destruction of the enzyme, or preserve membrane‐bound bodies containing the enzyme. It is suggested that phytokinins affect RNase synthesis directly and that this phase of leaf senescence is more fundamental to the life of the cells than mobilization phenomena.

show abstract

Section: Leaf Detachment and Phytokinin Treatmentmentioning

confidence: 99%

Section: Sampling For Ribonuclease Activity and Greennessmentioning

confidence: 99%

Section: Detached Leaves-effect Of N6-benzyladenine and Kinetin On Lmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Age‐governed Responses of Detached Tomato Leaves to Phytokinins

McHale

Dove

1969

New Phytologist

Self Cite

View full text Add to dashboard Cite

show abstract

“…Correlations between protein and/or enzyme levels and senescence of detached leaves have been made (1,2,8,9,11,13) …”

mentioning

confidence: 99%

Changes in Leaf Proteins of Peas, Pisum sativum L., during Development on Deflorated Plants

Malik

Berrie²

1977

Plant Physiol.

View full text Add to dashboard Cite

The soluble (sap) proteins of leaves of pea, Pisum sativum L. cvs.Alaska and Greenfeast, allowed to develop normally or deflowered, to prevent senescence, were separated by isoelectric focusing.There was a decdine in cerain proteins, with increases in others as the leaves aged but preventing senescence of the whole plat did not alter the pattern of change in leaf proteins. We conduded that wbole plant senescence proceeds independendy of leaf senescence.As detached leaves senesce, there is a decline of (12) and change in their proteins (4,15,16 MATERIALS AND METHODSThe tall, early Alaska and the mid-season dwarf Greenfeast cultivars of Pisum sativum L. were chosen for study, and plants were grown in an environmental cabinet set to provide the following: temperature, 18 C + 2 C; photoperiod, 18 hr; radiant flux at plant height, 17 wm-2 provided by Philips electrical WWX and daylight fluorescent lamps in equal ratio. The rooting medium was a soil-peat-gravel mixture in the ratio of 1:1:1 and nutrient was applied weekly, Hoagland solution as modified by Went (14) with water given as required. Isoelectric focusing from pH 3 to pH 10 was carried out as already described (6) using 10 ,ul of sap/analysis. Stained gels were scanned on a Joyce Loebl chromoscan and the resulting traces equalized for over-all length by a photographic procedure.In the case of detached leaves, the ninth node with segments of adjacent internodes was excised (cv. Alaska). The axillary buds were destroyed by crushing and the explant was placed in a test tube containing water. These were kept under the standard environmental conditions and protein analysis carried out 10 days from the time of taking the explant. RESULTS AND DISCUSSIONIn the cv. Alaska, there are relative changes in the major proteins of the sixth, ninth, and 11th leaves of normal and deflowered plants (Fig. 1). Over the pH range 10 to 5.25, 16 proteins can be seen in the isoelectrophoretogram of the 11th (youngest) leaf (Fig. 1 A) with that designated 3 the most prominent (presumably RuDP carboxylase).In Greenfeast, the analysis was carried out on leaves 14, 18, and 20 to correspond with the leaves of Alaska, viz., at a nonflowering node, the first flowering node and the third flowering node. Figure 2 presents these isoelectrophoretograms. The pattern for the youngest leaf ( Fig. 2A) is broadly similar to that in Alaska (Fig. IA). As the leaves age, there is a substantial increase in protein 1 and new peaks develop and increase between 1 and 2, 2 and 3 (best seen in Fig. 2) and on the shoulder of 5 (Fig. 3).The leaves from deflowered plants are qualitatively like normal and do not differ quantitatively as determined by our analytical procedure.The protein changes in the detached leaf are similar to those occurring in leaves attached to the plant but more emphasized.If it is assumed that the leaf has a standard protein complement when first expanded, our results indicate that the protein changes which occur as the leaf ages are not influenced by the condition of the whol...

show abstract