Physiologie. 233 



The average Variation between the maximum and minimum 

 percentage of waler in the leaves on a wet basis during ihe day 

 from 7 a. m. to 7 p.m. was 3.5 for corn, 3.2 for kafir and 4.5 for 

 railo. On the same basis the average Variation between the mini- 

 mum percentage of water during the day and the maximum 

 percentage during the night was 5.4, 5.9 and 6.0 rcspectively for 

 corn, kafir and milo. The average difference between the minimum 

 and maximum percentage of water on a dry basis during the day 

 from 7 a, m. to 7 p.m. was 39.5 for corn, 31.1 for kafir and 35.9 

 for milo. The average ränge between the maximum and minimum 

 water content on this basis during the night from 7 p.m. to 7 a. m. 

 was 37.5, 47,5 and 40.0 respectively for corn, kafir and milo, while 

 the average ränge between the minimum percentage of water on 

 this basis during the day and the maximum percentage at night 

 was 67.8 for corn, 67.2 for kafir and 51.2 for milo. 



The dry weight of a given area of milo leaf was always found 

 to be greater than an equal area of either corn or kafir leaves 

 leaves at the same stage of development. The average dry weight 

 of a Square meter of leaf for all the observations made was 48.2 

 gm. for corn, 52.5 gm. for kafir and 56.2 gm. for milo. The average 

 difference between the minimum and maximum amount of dry 

 matter in the leaves for each Square meter of leaf from 7 a. m to 

 7 p. m. was 4.0, 4.8 and 8.0 gm. respectively for corn, kafir and 

 milo. The increase in dry matter began at daybreak and the 

 maximum amount of dry matter in the leaves occurred in most 

 cases between 2 and 5 p.m. The rate of increase of the dry 

 matter in the leaves during the portion of the day when the 

 climatic conditions were severe was much higher for milo than 

 for either corn or kafir. 



The results indicate that under the conditions of these experi- 

 ments the sorghums and, more particulary, milo can absorb water 

 from the soil and transport it to the leaves more rapidly in propor- 

 tion to the loss of water from the plant than can corn. As a result 

 of this ability, the sorghums can produce more dry matter for 

 each Unit of leaf area under severe climatic conditions than the 

 corn plant. M. J. Sirks (Wageningen). 



Molisch, H., Der Tabakrauch und die Pflanze. (Urania. IX. 

 p. 265—267. 1916.) 

 Der sichtbare Tabakrauch besteht aus zahllosen, sehr kleinen 

 Flüssigkeitströpfchen, in denen verschiedene Verbrennungsprodukte 

 des Tabaks gelöst sind. Dies sind jene Tröpfchen, die sich im 

 Wassersacke der Pfeife als brauner Saft ansammelt. Einige Zeit 

 erhalten sie sich schwebend, nach und nach folgen sie der Schwere 

 und fallen zu Boden. Zieht man Pflanzen unter Glas in einer 

 mit Tabakrauch geschwängerten Luft, so wirken jene Tröpfchen 

 auf die Pflanzen immer noch ein, indem sie sich verfltichtigen, 

 wenn der Rauch auch für das Auge schon verschwunden ist. yer- 

 suche mit jungen Wicken zeigten, dass die Keimlinge in reiner 

 Luft bei Lichtabschluss ziemlich in die Länge wachsen und aufrecht 

 bleiben, die Stengel der „Rauchpflanzen" bleiben kurz, werden 

 dick, wachsen horizontal oder schief. Auf erwachsene Pflanzen 

 wirkt der Rauch verschieden ein: Blattbewegungen, Wucherungen 

 der Rindenporen oder Laubfall erzeugend, die Ruheperiode der 

 Knospen abkürzend. Matouschek (Wien). 



