Bernstein, Aaron, Naturwissenschaftliche Volksbücher, Bd. 6/11, 1897

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        <div xml:id="echoid-div241" type="section" level="1" n="173">
          <p>
            <s xml:id="echoid-s6862" xml:space="preserve">
              <pb o="41" file="525" n="525"/>
            Organen auftritt. </s>
            <s xml:id="echoid-s6863" xml:space="preserve">Die Baſtzellen ſelbſt ſind in der Jugend oft
              <lb/>
            collenchymatiſch, ſpäter jedoch treten ſie aus dieſem wachstums-
              <lb/>
            fähigen Zuſtand heraus. </s>
            <s xml:id="echoid-s6864" xml:space="preserve">In denjenigen Pflanzenteilen, in
              <lb/>
            welchen ein dauerndes Wachstum ſtattfindet, wie z. </s>
            <s xml:id="echoid-s6865" xml:space="preserve">B. </s>
            <s xml:id="echoid-s6866" xml:space="preserve">in den
              <lb/>
            Knoten der Grashalme, beſteht das mechaniſche Gewebe zeit-
              <lb/>
            lebens aus Collenchym. </s>
            <s xml:id="echoid-s6867" xml:space="preserve">Die Collenchymzellen ſind ebenfalls
              <lb/>
            — wie die vorerwähnten Baſt- oder echten Holzzellen — lang-
              <lb/>
            geſtreckt. </s>
            <s xml:id="echoid-s6868" xml:space="preserve">Ihre Wandungen ſind jedoch nur vorzugsweiſe in
              <lb/>
            den Kanten ungleichmäßig verdickt. </s>
            <s xml:id="echoid-s6869" xml:space="preserve">Während der Inhalt der
              <lb/>
            Baſt- reſp. </s>
            <s xml:id="echoid-s6870" xml:space="preserve">echten Holzzellen nun meiſt in Luft beſteht, führt
              <lb/>
            das im Gegenſatz zum Baſt alſo lebensfähige Collenchym ſtets
              <lb/>
            einen ſehr reichlichen Saft, der die Zellenwandungen ſtraff hält.
              <lb/>
            </s>
            <s xml:id="echoid-s6871" xml:space="preserve">Das Collenchym kann man mit dem Knorpel und die Baſt-
              <lb/>
            oder Holzzellen mit den Knochenzellen der Tiere vergleichen.</s>
            <s xml:id="echoid-s6872" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div243" type="section" level="1" n="174">
          <head xml:id="echoid-head200" xml:space="preserve">
            <emph style="bf">XVII. Die Bedeutung der Steinkörper im Frucht-</emph>
            <lb/>
            <emph style="bf">fleiſche der Birnen.</emph>
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          <p>
            <s xml:id="echoid-s6873" xml:space="preserve">In der Birne (Fig. </s>
            <s xml:id="echoid-s6874" xml:space="preserve">2 a) fallen kleine Gruppen von ſo-
              <lb/>
            genannten
              <emph style="sp">Steinzellen (= Hartgewebezellen, Skleren-
                <lb/>
              chymzellen)</emph>
            auf, die beim Verſpeiſen im Fruchtfleiſche als
              <lb/>
            harte, ſteinartige Körperchen ſich gern zwiſchen die Zähne
              <lb/>
            ſetzen. </s>
            <s xml:id="echoid-s6875" xml:space="preserve">Je nach der Sorte des Obſtes treten ſie in größerer
              <lb/>
            oder geringerer Menge im Fleiſche zerſtreut in die Erſcheinung.
              <lb/>
            </s>
            <s xml:id="echoid-s6876" xml:space="preserve">Jedes dieſer Körperchen beſteht aus mehreren Zellen, welche
              <lb/>
            verhältnismäßig ſtarke, von Kanälen durchſetzte Wandungen
              <lb/>
            beſitzen. </s>
            <s xml:id="echoid-s6877" xml:space="preserve">Die Steinzellen finden ſich nicht in den Birnen allein,
              <lb/>
            ſondern ſind im Pflanzenreich ſehr verbreitet; </s>
            <s xml:id="echoid-s6878" xml:space="preserve">ſie treten vor-
              <lb/>
            zugsweiſe als die Elementarbeſtandteile ſolcher Gewebe auf,
              <lb/>
            die dazu dienen, gewiſſen Pflanzenteilen Feſtigkeit zu </s>
          </p>
        </div>
      </text>
    </echo>
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