diff --git a/source/java/org/alfresco/repo/domain/PropertyValue.java b/source/java/org/alfresco/repo/domain/PropertyValue.java
index 654d8099dd..a0d21a3ccf 100644
--- a/source/java/org/alfresco/repo/domain/PropertyValue.java
+++ b/source/java/org/alfresco/repo/domain/PropertyValue.java
@@ -257,6 +257,7 @@ public class PropertyValue implements Cloneable, Serializable
             @Override
             protected ValueType getPersistedType(Serializable value)
             {
+                // NOTE: since 2.2.1, PropertyValue is only used by AVM (which does not natively support MLText, other than single/default string)
                 if (value instanceof MLText)
                 {
                     MLText mlText = (MLText) value;
@@ -269,7 +270,7 @@ public class PropertyValue implements Cloneable, Serializable
                         return ValueType.STRING;
                     }
                 }
-                else if (value instanceof String)
+                else if ((value == null) || (value instanceof String))
                 {
                     return ValueType.STRING;
                 }
diff --git a/source/java/org/alfresco/repo/domain/PropertyValueTest.java b/source/java/org/alfresco/repo/domain/PropertyValueTest.java
index e8cb1ddbb9..c816d6a3ee 100644
--- a/source/java/org/alfresco/repo/domain/PropertyValueTest.java
+++ b/source/java/org/alfresco/repo/domain/PropertyValueTest.java
@@ -51,7 +51,7 @@ public class PropertyValueTest extends TestCase
                 // single language
                 MLText mlText = new MLText(Locale.FRENCH, "bonjour");
                 PropertyValue propertyValue = new PropertyValue(DataTypeDefinition.MLTEXT, mlText);
-                assertNotNull("MLText not persisted as a string", propertyValue.getStringValue());
+                assertEquals("MLText not persisted as a string", "bonjour", propertyValue.getStringValue());
                 
                 try
                 {
@@ -69,6 +69,16 @@ public class PropertyValueTest extends TestCase
                     // NOTE: since 2.2.1, PropertyValue is only used by AVM (which does not natively support MLText, other than single/default string)
                 }
                 
+                // single language - empty string
+                mlText = new MLText(Locale.FRENCH, "");
+                propertyValue = new PropertyValue(DataTypeDefinition.MLTEXT, mlText);
+                assertEquals("MLText not persisted as an empty string", "", propertyValue.getStringValue());
+                
+                // single language - null string
+                mlText = new MLText(Locale.GERMAN, null);
+                propertyValue = new PropertyValue(DataTypeDefinition.MLTEXT, mlText);
+                assertNull("MLText not persisted as a null string", propertyValue.getStringValue());
+                
                 return null;
             }
         };