A Rapid Non-destructive Method for the Estimation of Leaf Areas in Cassava

A rapid and non-destructive method of estimating leaf areaswas required for detailed study of new cassava varieties. Theoutlines of leaves were traced in the field and leaf areas wereobtained with a planimeter. Variety Caricass 2 was chosen fordetailed study and 50 leaves of each lobe number (three to ninelobes per leaf) were measured. The length and width were recordedfor all lobes and correlations were made with leaf areas. Alllobe lengths and length x width were highly correlated withleaf area. It is therefore necessary to measure the length ofonly one lobe to get an estimate of leaf area. Comparisons ofleaves with five and seven lobes from Caricass 1, Caricass 3and a local variety showed that these varieties could be measuredin the same way and that the regression coefficient for Caricass2, Caricass 3 and the local variety were not significantly different.A common regression coefficient could be used to estimate leafarea on all three varieties. Manihot esculenta Crantz, cassava, root crop, leaf area     

Identification of Mouse Haemoglobin Messenger RNA

RETICULOCYTE polyribosomes contain 9S RNA with many of the properties expected for the haemoglobin messenger RNA (mRNA)^1–12. Proof that this RNA is the haemoglobin (Hb) mRNA, however, can be obtained only by showing that it directs the synthesis of globin chains. Laycock and Hunt¹³ added an RNA isolated from rabbit reticulocytes to an E. coli cell-free preparation and observed the synthesis of material, with the properties of globin in the presence of N-acetylvalyl tRNA. We added the mouse reticulocyte 9S RNA to a rabbit reticulocyte cell-free system and have shown that material is synthesized which co-chromatographs with mouse globin β-chains¹⁴. We now present evidence that the material synthesized under the direction of the mouse 9S RNA is indeed mouse haemoglobin β-chains.     

Synergism between Gibberellin and Auxin in the Growth of Intact Tomato

Gibberellin A_4&7 was more effective than gibberellic acid in increasing shoot elongation when applied to the apex of intact Lycopersicum esculentum seedlings of Tiny Tim, a dwarf cultivar, and Winsall, a tall cultivar. After 14 days, gibberellic acid and gibberellin A_4&7 stimulated growth of the dwarf more than the tall tomato. In tall tomato the application of indole-3-acetic acid alone (6.1 μg/plant) showed an inhibitory growth effect, but when applied with 17.5 μg per plant of gibberellic acid, it had a synergistic effect at 7 days but not at 14 days. When the auxin concentration was reduced to 0.61 μg per plant a synergistic effect was observed on tall plants at 7 and 14 days between indole-3-acetic acid and gibberellic acid. Application of gibberellin A_4&7 with auxin did not give a synergistic response in tall or dwarf tomato.     

Abscisic Acid and Gibberellin-in Three Ungrafted Apple (Malus sylvestris) Rootstock Clones

ABA and gibberellin-like substances were extracted from roots, shoots, and leaves of most dwarfing M9, semi-dwarfing MM 106, and least dwarfing MM111 apple rootstock plants. Among tissues, the roots contained the largest and the shoots the smallest amounts of all the phytohormones studied. Plants of M9 contained the highest and MM111 the lowest ABA-like substances in all tissues tested. Gibberellin₄₊₇-like compounds were at the highest levels in the roots of MM111 and lowest in the roots of M9, whereas GA₃-like substance was in the reverse order. All three gibberellin-like compounds were highest in the shoots and leaves of MM111 and lowest in the respective tissues of M9 clone. Role of these phytohormones in the dwarfing mechanism is discussed.     

The Levels of Macro- and Micronutrients in the Beans of Cacao (Theobroma Cacao L.) in relation to Shade, Fertilizer, Irrigation, and Season

The levels of nutrients in ripe beans collected over a periodof 16 months from a field trial were not affected by shade andirrigation treatments, but addition of fertilizer increasedthe levels of phosphorus and manganese and decreased the levelsof copper and molybdenum in the beans. The levels of nutrientsin the beans did not vary appreciably throughout the period.Potassium was the only element which showed a systematic seasonalvariation of content, with the highest level in March and asteady decline to the lowest level in October. The mean ashcontent and levels of twelve nutrients in the beans are reported,as well as the seasonal maxima and minima.     

The Levels of Nitrogen, Phosphorus, Potassium, Calcium and Magnesium in the Leaves of Cacao (Theobroma Cacao L.) as affected by Shade, Fertilizer, Irrigation, and Season

The results are given of chemical analyses of leaves collectedover a period of two years from cocoa trees in a field trialreceiving fertilizer, shade, and irrigation treatments. Thegreatest variation in concentration of nutrients in the leaveswas due to the time of year the leaves were collected. The lowestconcentrations of nitrogen, phosphorus, and potassium were foundin the leaves collected during the peak of the main season harvest.The highest levels of these elements were found in leaves collectednear the end or a few weeks after the end of the main harvest.The levels of calcium in the leaves were just opposite, withthe highest levels coinciding with harvest and the lowest levelsoccurring just after the harvest period. The levels of magnesiumshowed no marked variations between seasons. Shade increased the levels of nitrogen, phosphorus, and potassium,and decreased the levels of calcium in the leaves. Fertilizerincreased the levels of nitrogen, phosphorus, calcium, and magnesium,and decreased the level of potassium in the leaves. The effectof irrigation was small, but it decreased the levels of nitrogen,potassium, calcium, and magnesium in the leaves. The levels of nitrogen, phosphorus, and potassium in the leavesover the 21 harvesting times were found to be positively correlatedwith each other, and all three were negatively correlated withthe levels of calcium in the leaves over the same period. Noneof the levels of these four elements was significantly correlatedwith the levels of magnesium in the leaves over the period.     

The Levels of Manganese, Sodium, Aluminium, Iron, Boron, Zinc, and Copper in the Leaves of Cacao (Theobroma cacao L.): As Affected by Shade, Fertilizer, Irrigation, and Season

The results are given of chemical analyses of leaves collectedover a period of one year from cacao trees in a field trialreceiving fertilizer, shade, and irrigation treatments. Thegreatest variation in concentration of the elements under studywas found to be due to the time of year at which the leaveswere collected. The lowest concentrations of zinc and copperwere found in the leaves collected during the peak of the mainseason crop. The lowest concentrations of manganese, aluminium,and iron were found in leaves collected about a month afterthe end of the main harvest. The levels of most elements rosesharply after the end of the main harvest. The levels of mostelements rose sharply after reaching a minimum, and the maximumlevels were usually reached before completion of flowering forthe next main season crop. The effects of the treatments onthe nutrient levels in the leaves were generally small. Thefertilizer treatment tended to increase the levels of manganese,aluminium, iron, sodium, and zinc and to decrease the levelof boron. The shade treatment tended to increase the levelsof sodium, copper, and zinc and to decrease the levels of manganese,aluminium, and iron. The irrigation treatment had no substantialeffect on the level of any element. The levels of iron, manganese,and boron, were found to be positively correlated with the levelof aluminium.