0 a type of chemical found in plants that often acts as a drug or poison, or is used in medicines -- 生物鹼（植物中的化學物質，常用於製藥或作為毒物）
In many leaves, alkaloid concentrations range from 100 to 500 g g-1 fresh weight.
Most of the alkaloids and flavonoids are present in the flowers and in the ripe fruits.
The administered doses of alkaloid and flavonoid fractions correspond to the proportion of these components in the crude extract used in the experiment.
Coffee plants contain alkaloid compounds that discourage herbivory.
This equation was also used to quantify consumption of saponins, cyanogenic glycosides and alkaloids.
A colour change from white to orange indicates presence of alkaloid or related amines.
No differences were detected between lipid-poor and -rich seasons in levels of alkaloids, fibre or saponins.
It is not known whether disproportionately higher levels of alkaloids in other tissues, principally the phloem, contribute to this aphid resistance.
