Leaf position

Carnegie, S.F. and Colhoun, J. (1982). Susceptibility of potato leaves to Phytophthora infestans on potato plants in relation to plant age and leaf position , Phytopathology. Z, 104, 157-167. 

Degraded broad-leaf Positive correlation for Soil extractable P Fu et al. 

Position 1 is that of the youngest fully expanded leaf. Position 3 and 4 are consecutively lower down the stem. 

Young tomato plants having four leaves were wounded at the leaf position shown below with a hemostat at 0 and 72 hr. After 120 hr following the initial wounding the terminal leaflet of each leaf was assayed for Inhibitor I concentration. 

Effect of Leaf Position on the Rate of Photosynthesis and Transpiration... 

The effect of leaf position on the photosynthetic rate of Jerusalem artichoke (Soja and Haunold, 1991) is similar to that of the sunflower (English et al., 1979) in that leaf position becomes progressively more critical as the plant ages. When the plants reach their final height, only leaves in the upper 1/6 of the canopy display gas exchange rates greater than 50% of the most apical leaves (Table 10.3). 

Bereman, M., N. Glassbrook, J. Eaton, F. Jaeger and R.D. Bereman Determination of pyrrobdine in tobacco leaves by tobacco type and leaf position 57th Tobacco Science Research Conference, Program Booklet and Abstracts, Vol. 57, Paper No. 36, 2003, p. 41. 

The oxygen evolution of leaf discs in two clones af Ficus benja-jamina L. showed no differences with respect to leaf positions on young plants (2, Ottosen unpubl.). 

Leaf Position on shoot Growing PPFD M-E m s Reaction PPFD pE m s Per cent value for Fashion ... 

Net oxygen flux of leaf segments was influenced by cultivar, leaf position, photoperiod and reaction PPFD. Shoot dry weight was influenced by cultivar, probably by photosynthesis, as well as growing PPFD, SO2 and photoperiod. In each case, there were numerous interactions between these factors. 

FIGURE 2. Tiae courses of ACXI stiHulated ethylene release by leaf tissue froM leaf position five of twelve leaf topato plants grown under a) awbient (360 ubar) and b) enriched (1300)... 

FIGURE 4. Maximal leaf conductance as related to CO assimilation under optimal climnatic conditions and ambient CO2/ and CO2 assimilation as related to leaf nitrogen content and leaf position. The leaf nodes are counted with the youngest developing leaf being node number 1. 

In ambient air, 2nd leaf (LPI-2) showed higher Net Carbon dioxide Exchange Rate (NCER) as well as RuBP carboxylase activity than the 5th leaf (LPI-5I) of the same age, while the 12 day old leaf had higher NCER and RuBP carboxylase activity than the 18 day old 5th leaf (LPI-5II). On enrichment with 600 and 900 ul 1 1 CO2 2nd leaf showed a much higher NCER than the 5th leaf of same age. Similarly, the younger 5th leaf showed more response than the older 5th leaf. It appears that leaf position as well as leaf age, both affect the response to elevated CO2 but the leaf position is more effective of the two (Table 1). 

Comparison of carbon allocation and partitioning of allocated carbon into starch and sugars in the source leaves showed that leaf at 5th node was a better exporter (54%) than the leaf at 2nd node (32%) of same age (Table 2). This allocation of fixed carbon to the source leaf at a particular leaf position may be influenced by the nature of the sink and the sink demand. Sinks in these two cases were functionally and metabolically distinct. 

J. Rohloff, Monoterpene composition of essential oil from peppermint with regard to leaf position using solid-phase microextraction and gas chromatography/mass spectrometry analysis, J. Agric. Food Chem. 47(9) 3782 (1999). 

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