User Guide

15
PHOSPHORUSPHOSPHORUS
PHOSPHORUSPHOSPHORUS
PHOSPHORUS
Phosphorus (P) has an important role in many fundamental biochemi-
cal and physiological processes. Plants take up phosphorus in the form
of phosphate ion (PO
4
3-
).
PRESENT IN DNA and RNA, ATP, ADP
ACTION • stimulates the roots growth
• stimulates blooming
• stimulates fecundation and ripeness
• strengthens the plant tissues
• is necessary in the formation of seeds
SHORTAGE • delayed ripening
EFFECTS • slower growth
• small leaves
• decrease of production (smaller fruits and difficult
seeds formation)
• reduction of root system
EXCESS EFFECTS • premature ripening
• excess of fruit-setting
• negative effects on the absorption of some micro-
elements such as iron, zinc, boron and copper
POTASSIUMPOTASSIUM
POTASSIUMPOTASSIUM
POTASSIUM
Potassium (K) is essential in proteic synthesis. The problem of lack of
potassium is quite frequent in calcareous soils.
Potassium is absorbed as K
+
.
PRESENT IN tissues responsible for the growth of plants (primary
and secondary meristems), embryos and cell vacuole
ACTION • improves the quality of fruits and flowers
• gives more resistance both to frost and to
diseases caused by fungi (increases the cuticular
thickness)
• regulates the cellular turgidity (helps to regulate the
osmotic processes and increases the resistance to
dryness)
• regulates the stomatic opening and closing (it means
a strong influence on transpiration and photo-
synthesis)
SHORTAGE • slower growth
EFFECTS • smaller fruits, less colored and less preserved
• increase of transpiration
• less resistance to the cold
46
• Press ZERO and “SIP” will appear on the display.
• Wait for a few seconds and the display will
show “-0.0-”. Now the meter is zeroed and
ready for measurement.
• Remove the cuvet and add
the content of one packet
of HI 93750B reagent. Re-
place the cap and mix
gently for one minute by
turning slowly the cuvet up-
side down.
• Reinsert the cuvet into the instrument.
• Press TIMER and the display will show the countdown prior to the
measurement or, alternatively, wait for 2 minutes and press READ
DIRECT. In both cases “SIP” will blink during measurement.
• The instrument directly displays concentration in mg/L of potassium
(K) on the Liquid Crystal Display.
• To convert the reading to mg/L of potassium oxide (K
2
O), multiply
by a factor of 1.20.
INTERFERENCES
The following ions do not interfere below the concentrations reported:
Ammonium 10 ppm
Calcium 10000 ppm as CaCO
3
Chloride 12000 ppm
Magnesium 8000 ppm as CaCO
3
Sodium 8000 ppm
Potassium LR